CN105160066B - Consider the crashworthiness part emulation design method of shaping damage - Google Patents

Abstract

The invention discloses a kind of crashworthiness part emulation design methods for considering shaping damage, with ignore when solving the problems, such as vehicle body high intensity crashworthiness part design of Simulation existing in the prior art part different parts shaping damage inherited characteristics caused by subsequent simulation computational accuracy deficiency and structural design of fittings it is unreasonable, step is：Establish vehicle body high intensity crashworthiness part hot forming damage criterion；The hot forming of vehicle body high intensity crashworthiness part is simulated；Vehicle body high intensity crashworthiness part crashworthiness Simulation Evaluation.This method has considered forming temperature, shaping rate, rub the factor considered when " the shaping impairment value " after the part forming simulation of factors is assessed as part crashworthiness, significantly improve the precision of subsequent simulation calculating, reduce the number changed repeatedly, it ensures the reasonability of structural design of fittings, greatly reduces the difficulty of crashworthiness part design of Simulation and the requirement to designer.

Description

Consider the crashworthiness part emulation design method of shaping damage

Technical field

The present invention relates to vehicle body high intensity crashworthiness part, it more particularly relates to which a kind of consider what shaping damaged Vehicle body high intensity crashworthiness part emulation design method.

Background technology

In recent years, energy crisis and environmental problem cause Lightweight Technology to become the focus of automobile industry.How to ensure On the premise of vehicle body minibus, realize that body lightening becomes the hot issue in lightweight field.Superhigh intensity boron steel is high with it The advantages such as loss of weight potentiality, high collision energy-absorbing, high-fatigue strength and low degree anisotropy, it has also become the main material of auto industry Material, is widely used in vehicle body crashworthiness part, such as：A/B/C columns, sill strip, side girders, on door anti-collision joist.However, with steel The raising of plate intensity, forming property also accordingly deteriorate, and can generate that rebound is serious, shaping is tired using conventional ones forming technology The problems such as difficult, easy cracking.In order to overcome the problems referred above, high strength steel hot forming techniques come into being, and detailed process is： Boron steel is heated to 900 DEG C or so, microstructure is made to be converted into uniform austenite by ferrite+pearlite, then with Stamping in the mold of cooling system, pressurize rapid quenching cooling simultaneously makes austenite be completely transformed into martensite, significantly Improve part strength.

As computer simulation technique reaches its maturity, the method design vehicle body high intensity that people start with numerical simulation resists Part is hit, design process is broadly divided into two steps：After heat forming processes and the forming simulation of simulating vehicle body high intensity crashworthiness part The assessment of part crashworthiness.At this stage, emulation technology can plate is suffered preferably in the actual forming process of simulation should The coupling of power-phase transformation-temperature three, can obtain the part model after forming simulation, it can accurately be predicted Stress distribution, phase composition, Temperature Distribution, thickness distribution of part etc. after actual shaping.But actual heat forming processes Dislocations Density changes with shaping, and material is caused to generate microlesion (Micro-v oid and micro-crack), develops and extension generates rupture and loses Effect, can produce a very large impact part performance.And the part crashworthiness evaluation stage after forming simulation, often because ignoring The shaping " damage " generated in part heat forming processes and the otherness of different parts degree of injury, it is believed that entire part is reason The martensitic phase material thought, and influence subsequent simulation calculating precision in addition can because excessively high had estimated in emulation shaping after zero The crashworthiness of part causes the generation of unreasonable structure design in actual production.

It can be in the crashworthiness evaluation stage after vehicle body high intensity crashworthiness part forming simulation therefore, it is necessary to a kind of method Hot forming damage is taken into account, improves the Evaluation accuracy of its crashworthiness, enhances vehicle body high intensity crashworthiness part design of Simulation To the directive significance of actual design so that the vehicle body high intensity crashworthiness part of actual design more easily reachs design object requirement, So as to reduce test number (TN), shorten the construction cycle, reduce development cost.

The content of the invention

The technical problems to be solved by the invention are to overcome vehicle body high intensity crashworthiness part emulation existing in the prior art Ignore the subsequent simulation computational accuracy deficiency and design of part caused by part different parts shaping damage inherited characteristics during design The problem of unreasonable is designed, provides a kind of crashworthiness part emulation design method for considering shaping damage, specific technical solution is such as Under：

Consider the crashworthiness part emulation design method of shaping damage, it is characterised in that step is as follows：

Step 1: establishing vehicle body high intensity crashworthiness part hot forming damage criterion, detailed process is：

1) material at high temperature one directional tensile test

A series of high temperature one directional tensile tests are carried out to boron steel test specimen using hot modeling test machine, mash welder is utilized before experiment One end of K-type thermocouple wire (1) is welded in the center of each test specimen (2) upper surface, K-type thermocouple wire (1) other end is kept certainly By discharging, first test specimen (2) is clamped in the fixture of hot modeling test machine in experiment, while K-type thermocouple wire (1) is freely released The one end put is connected with hot modeling test machine, then, carries out vacuumize process to hot modeling test machine inner space, utilizes resistance Mode of heating realizes the heating process of test specimen (2), and then by adjusting the flow control test specimen (2) of compressed air in cooling procedure Cooling velocity, specific testing program is as follows：

(1) keep the temperature 3min after test specimen (2) being heated to 925 DEG C with the rate of heat addition of 5 DEG C/s, it is ensured that test specimen (2) it is microcosmic Organize complete austenitizing；

(2) with the cooldown rate of 50 DEG C/s make test specimen (2) be down to successively 600 DEG C of deformation temperature, 700 DEG C, 800 DEG C, and 5s is kept the temperature under each deformation temperature makes test specimen (2) temperature uniform and stable；

(3) in 600 DEG C, 700 DEG C, 800 DEG C of the deformation temperature and deformation strain rate 0.01s of setting^-1、0.1s^-1、1s^-1、 10s^-1Under test specimen (2) is stretched, test specimen (8) after obtained stretching is carried out until rupture failure, after fracture it is air-cooled, entirely Thermal modeling test chance records the curve that load changes over time, temperature changes over time, entire high temperature simultaneously in drawing process One directional tensile test includes 12 groups of experimental conditions that 3 deformation temperatures and 4 deformation strain rates are combined into, and is respectively：Deformation temperature 600 DEG C of degree and deformation strain rate 0.01s^-1, 600 DEG C of deformation temperature and deformation strain rate 0.1s^-1, 600 DEG C of deformation temperature and deformation Strain rate 1s^-1, 600 DEG C of deformation temperature and deformation strain rate 10s^-1, 700 DEG C of deformation temperature and deformation strain rate 0.01s^-1, deformation 700 DEG C of temperature and deformation strain rate 0.1s^-1, 700 DEG C of deformation temperature and deformation strain rate 1s^-1, 700 DEG C of deformation temperature and deformation Strain rate 10s^-1, 800 DEG C of deformation temperature and deformation strain rate 0.01s^-1, 800 DEG C of deformation temperature and deformation strain rate 0.1s^-1, become 800 DEG C of shape temperature and deformation strain rate 1s^-1, 800 DEG C of deformation temperature and deformation strain rate 10s^-1, carry out under every group of experimental condition High temperature tension test, the curve F (t) that the load that hot modeling test machine in experiment measures is changed over time is according to formula (1) it is scaled the curve σ that the nominal stress of test specimen (2) changes over time_nom(t), the test specimen (2) CCD camera (3) measured The curve Δ L (t) that changes over time of gauge length segment length according to formula (2) be scaled the gauge length section apparent strain of test specimen (2) with The curve ε of time change_nom(t), the curve σ changed over time the nominal stress of test specimen (2) according to formula (3)_nom(t) convert The curve σ changed over time for the true stress of test specimen (2)_trueIt (t), should by the gauge length section name of test specimen (2) according to formula (4) Become the curve ε changed over time_nom(t) it is scaled the curve ε that the gauge length section logarithmic strain of test specimen (2) changes over time_true(t), And the time variable t in two curves is eliminated, with logarithmic strain ε_trueFor independent variable, true stress σ_trueFor dependent variable, obtain each True stress and strain curve σ under experimental condition_true(ε_true)：

In formula：F (t) is the curve that load changes over time；A₀For specimen equidistance line marking section original cross-sectional area；σ_nom(t) it is examination The curve that the nominal stress of part changes over time.

In formula：Δ L (t) is the curve that the gauge length segment length of test specimen changes over time；L₀For specimen equidistance line marking section original length； ε_nom(t) curve changed over time for the gauge length section apparent strain of test specimen.

σ_true(t)=σ_nom(t)(1+ε_nom(t)) (3)

In formula：σ_nom(t) curve changed over time for the nominal stress of test specimen；ε_nom(t) it is the gauge length section name of test specimen Strain the curve changed over time；σ_true(t) curve changed over time for the true stress of test specimen.

ε_true(t)=ln (1+ ε_nom(t)) (4)

In formula：ε_nom(t) curve changed over time for the gauge length section apparent strain of test specimen；ε_true(t) it is the gauge length of test specimen The curve that section logarithmic strain changes over time.

2) constitutive equation based on shaping damage is established：

(1) constitutive equation based on shaping damage is established, the damage of material during considering hot forming, expression is such as Under：

In formula：Equivalent plastic strain rate when being shaping；σ_eEquivalent stress when being shaping；By dislocation when H is shaping Caused strain hardening；Shape damage variable f_d1, excursion is 0~1, f_d1Represent that material does not damage during shaping when=0 Wound, f_d1Represent that material is entirely ineffective during shaping when=1；Plastic strain rate component during to shape；S_ijPartially should during to shape Force component；ρ_iFor the dislocation density under material original state, ρ_mMaterial accessible maximum during to shape Dislocation density, and ρ_i≤ρ≤ρ_m, i.e.,σ_ijStress tensor component when being shaping；Overall strain when being shaping Measure component；Plastic strain component of tensor when being shaping；D_ijklIt is quadravalence Stiffness Tensor component；E is Young's modulus；υ is pool Loose ratio；δ_ijFor the Kronecker factor, subscript i, j, k, l excursion are 1~3, repeat subscript and follow Einstein's summation convention.

Parameter k, K, n₁, B, C, D, E be with the relevant material parameter of temperature, be defined as follows：

K=k₀exp(Q_k/RT) (12)

K=K₀exp(Q_K/RT) (13)

n₁=n₁₀exp(Q_n/RT) (14)

B=B₀exp(Q_B/RT) (15)

C=C₀exp(-Q_C/RT) (16)

D=D₀exp(Q_D/RT) (17)

E=E₀exp(Q_E/RT) (18)

In formula：R is universal gas constant；T is temperature；Q is activation energy.

(2) material parameter in constitutive equation is determined：

First, the object function of Solve problems is established, then object function application Evolutionary Programming Algorithm is optimized, most Material parameter in definite constitutive equation eventually, here, it is thus necessary to determine that a total of 20 of material parameter, be followed successively by：A、n₂、γ₁、 γ₂、k₀、n₀、K₀、n₁₀、B₀、C₀、D₀、E₀、Q_k、Q_K、Q_n、Q_B、Q_C、Q_D、Q_E、R。

Object function is established according to the distance between matched curve and test data：

In formula：F (x) is to form vector x=(A, n on 20 unknown material parameters₂,...,Q_E, R) real-valued function； N is the total capacity of test data；w_iFor the weighted value of the i-th data point；The corresponding stress of respectively i-th of test data And strain value；Respectively with the stress and strain value in the corresponding matched curve of i-th of test dataIt is restrained for matched curve is made to strain section to test data, it willF (x) is added in obtain It arrives：

In formula：W is weight coefficient；

To reduce the difficulty of definite weighted value in actual use and overcoming the problems, such as that ess-strain unit is inconsistent, most The object function established eventually is as follows：

In formula：

The object function of foundation is optimized using improved tachytelic evolution planning algorithm, determines all material parameter, Evolutionary Programming Algorithm is using object function as biotic population, and by mutation, selection generates population of new generation；This process is repeated, It is the process of an iteration until obtaining the population to meet the requirements or defined evolution time limit, detailed evolutional programming：

[1] iteration count k=1 is taken, generates μ population at random, i.e. stochastic inputs μ groups vector is to (x_i,η_i), whereinη_iFor evolutional programming adaptive strategy parameter, i=1,2,3 ..., μ；

[2] for each individual vector to (x_i,η_i), calculate f (x_i)；

[3] for each parent vector to (x_i,η_i), generate two filial generation vectors pairWithWherein：

It calculates and comparesWithSize, both take the vector pair corresponding to smaller, be denoted as (x_i', η_i'), wherein x_i(j), x_i' (j), η_i(j), η_i' (j) be respectively vector x_i, x_i', η_i, η_i' j-th of component (j=1,2 ..., N, n are the number of material parameter to be optimized)；N (0,1) is the random number for obeying one-dimensional standardized normal distribution；N_j(0,1) it is obedience One-dimensional standardized normal distribution corresponds to the random number of j-th of component；δ_jCorrespond to the random of j-th component to obey Cauchy's distribution Number；Parameter τ¹It is taken respectively with τWithStandardized normal distribution and the density function of Cauchy's distribution are respectively：

[4] for all i=1,2,3 ..., μ, by all parent vectors to (x_i,η_i) and filial generation vector to (x_i', η_i') as an entirety, q vector pair is taken out, then, by all parents and any one vector pair of filial generation vector centering The q vector with taking-up compares vector to corresponding target function value, if the vector is to being less than q vector to making comparisons Some of centering, then the vector add 1 to score, the top score of all vectors pair is q, minimum to be scored at 0；

[5] μ vector pair of highest scoring, the parent vector pair as next iteration are selected from 2 μ vectors pair；

[6] judge whether iteration termination condition meets；It is such as unsatisfactory for, then k=k+1, and repeats the above process.

(3) software of damage Constitutive Equation is realized

The shaping damage Constitutive Equation for having determined that material parameter is written as Ls-dyna user certainly using Fortran language Definition material subprogram is embedded by User Defined material subprogram interface in finite element software Ls-dyna.

Step 2: the hot forming of vehicle body high intensity crashworthiness part is simulated, detailed process is：

1) vehicle body high intensity crashworthiness part hot forming simulation model is established using Hypermesh finite element softwares, in model Object include plate (6), punch-pin (4), cavity plate (7) and blank holder (5)；

2) it is respectively each object imparting section attribute and material property in model, all objects are using shell unit section category Property, and the thickness t of each object is defined wherein, and punch-pin (4), cavity plate (7) and blank holder (5) use rigid body physical material, and Define density p, elastic modulus E and the Poisson's ratio υ of each object wherein, and plate (6) is then using above-mentioned based on shaping damage User Defined physical material, and all objects are using isotropism hot material, and define the specific heat capacity of each object wherein HC and coefficient of heat conduction TC；

3) contact relation in model between each object is set, defines temperature field, kinetic characteristic that each object has, constraint item Part and model calculate required control card；

4) using Ls-dyna softwares solve vehicle body high intensity crashworthiness part hot forming simulation model, zero after being shaped Part model and its shaping damage cloud atlas and thickness distribution cloud atlas.

Step 3：Vehicle body high intensity crashworthiness part crashworthiness Simulation Evaluation：

1) mechanics uses property database

(1) material at high temperature damage test

Virtual test is carried out to test specimen (2) using Ls-dyna softwares, entire test specimen (2) uses shell unit section attribute, and Its thickness t is defined wherein, using the User Defined physical material and isotropism hot material for considering shaping damage, and at it Defined in its specific heat capacity HC and coefficient of heat conduction TC, meanwhile, define l in test specimen (2) intermediate region₀The equal temperature section of=25mm long, Apply steady temperature field in the section, and at left and right sides of this section region then according to actual tests in test specimen (2) Temperature Distribution apply Add corresponding temperature field, during virtual test, all 6 degree of freedom of constraint test specimen (2) left end node apply vertically in right end The forced displacement changed over time, it is ensured that equal temperature section is deformed with constant strain rate, and equal temperature section is made to take typically in experiment Experimental condition：750 DEG C of forming temperature, deformation strain rate 0.1s^-1.Under this condition, a series of virtual tests are carried out, make equal temperature section The shaping impairment value of interior unit respectively reaches target shaping impairment value 0, α₁,α₂,......,α_nHave to get to a series of equal temperature sections There is test specimen (8) after the stretching of differing formed impairment value, and measure the changing value of each test specimen (2) samming segment length respectively

Actual tests are carried out to test specimen (2) using testing machine, actual test conditions are identical with virtual test, utilized in experiment CCD camera (3) is shot, and passes through the deflection of ARAMIS optical skew system Real-time Feedback test specimens (2) temperature section, when Each test specimen (2) samming segment length variation respectively reachesWhen, stop stretching, at this point, in actual tests Material reaches with equal degree of injury in virtual test at temperature section, same samming segment length changing value Repeated m time experiment in experiment. Then, each test specimen (2) temperature section rapid quenching is cooled to room temperature has differing formed impairment value to get to a series of equal temperature sections Quenching after martensitic phase stretching after test specimen (8).

(2) test specimen is processed

Linear cutter is carried out to test specimen (8) after a series of quenched stretchings for being obtained in material at high temperature damage test, It obtains for sub- test specimen (9) used in material room temperature one directional tensile test, then, with fine sandpaper to each surface of all sub- test specimens (9) It is slightly polished, removes oxide skin above, and record the minimum sectional area of each sub- test specimen (9) gauge length section after polishing, as The original cross-sectional area A of materials described below room temperature one directional tensile test neutron test specimen (9) gauge length section₀。

(3) material room temperature one directional tensile test

There is the son of different impairment values using electronic universal tester to the equal temperature section obtained in material at high temperature damage test Test specimen (9) carries out the one directional tensile test of m kind difference military service strain rates, and all sub- test specimens (9) are stretched at room temperature until disconnected It splits, the curve F (t) that chance record load changes over time is tested in entire drawing process, and it is scaled according to formula (1) The curve σ that the nominal stress of sub- test specimen (9) changes over time_nom(t), the gauge length of sub- test specimen (9) is measured using stretching to extend The curve Δ L (t) that segment length changes over time, and it is scaled to the gauge length section apparent strain of sub- test specimen (9) according to formula (2) The curve ε changed over time_nom(t), the curve σ changed over time the nominal stress of sub- test specimen (9) according to formula (3)_nom(t) It is scaled the curve σ that the true stress of sub- test specimen (9) changes over time_true(t), according to formula (4) by the gauge length of sub- test specimen (9) The curve ε that section apparent strain changes over time_nom(t) it is scaled the song that the gauge length section logarithmic strain of sub- test specimen (9) changes over time Line ε_true(t), and the time variable t in two curves is eliminated, with logarithmic strain ε_trueFor independent variable, true stress σ_trueFor because becoming Amount, obtains the true stress and strain curve σ of each test specimen (9)_true(ε_true).Finally, obtain with differing formed impairment value, difference The true stress and strain curve σ of the test specimen (9) of military service strain rate_true(ε_true), for establishing following clothes for considering shaping damage Use as a servant constitutive equation.

2) the military service constitutive equation for considering shaping damage is established

The military service constitutive equation for considering shaping damage is established, expression is as follows：

In formula：It is equivalent plastic strain rate when being on active service；σ is equivalent stress when being on active service；Military service damage variable f_d2, Its excursion is 0~1, f_d2Material is not on active service damage when representing to be on active service when=0, f_d2Material is complete when representing to be on active service when=1 Failure；Plastic strain rate component during to be on active service；S_s-ijDeviatoric stress component during to be on active service；ρ_si For the dislocation density of material before military service, ρ_smMaterial accessible maximum dislocation density during to be on active service, and ρ_si≤ρ_s≤ρ_sm, i.e.,σ_s-ijIt is stress tensor component when being on active service；It is overall strain component of tensor when being on active service；It is when being on active service Plastic strain component of tensor；D_s-ijklIt is quadravalence Stiffness Tensor component；L is Young's modulus；υ is Poisson's ratio；δ_ijFor Kronecker because Son, subscript i, j, k, l excursion are 1~3, repeat subscript and follow Einstein's summation convention.

Parameter y, Y, F, G, L, β₁、β₂、β₃、γ₅、γ₆It is to damage relevant material parameter with shaping, is defined as follows：

Y=y₀exp(W_y/f_d1) (33)

Y=Y₀exp(W_Y/f_d1) (34)

F=F₀exp(W_F/f_d1) (35)

G=G₀exp(-W_G/f_d1) (36)

L=L₀exp(W_L/f_d1) (37)

Used in the definite military service Material Parameter in Constitutive Equation for considering shaping damage and the realization of military service constitutive equation software Method used is identical when method is with establishing based on shaping damage Constitutive Equation, and here, it is thus necessary to determine that material parameter It a total of 25, is followed successively by：Z、γ₃、γ₄、γ₇、n_c、y₀、Y₀、F₀、G₀、L₀、β₁₀、β₂₀、β₃₀、γ₅₀、γ₆₀、W_y、W_Y、W_F、W_G、 W_L、

3) vehicle body high intensity crashworthiness part virtual test

(1) vehicle body high intensity crashworthiness part virtual test model, virtual crushing test mould are established using Hypermesh softwares Object in type includes：Rigid obstacle (10), conquassation thin-walled crashworthiness part (11)；Object bag in virtual bend test model It includes：No. 1 rigidity circle rolling (12), bending thin-walled crashworthiness part (13), No. 2 rigidity circle rollings (14), No. 3 rigidity circle rollings (15)；

(2) it is respectively each object imparting section attribute and material property in model, all objects are using shell unit section Attribute, the thickness distribution of crashworthiness part inherit the thickness distribution of part after hot forming, rigid obstacle (10) and all rigidity circle rollings Using rigid body physical material, and density p, elastic modulus E and the Poisson's ratio υ of each object are defined wherein, and be crushed thin-walled and resist It hits part (13) and bends thin-walled crashworthiness part (13) and be then on active service this structure physics material using the User Defined for considering shaping damage Material；

(3) contact relation in model between each object is set, defines the kinetic characteristic, constraints and model meter of each object Control card needed for calculating；

(4) vehicle body high intensity crashworthiness part virtual test model is solved using Ls-dyna softwares, output crashworthiness part is at any time Between the deformation tendency cloud atlas, the contact force curve and energy absorption curve that change, and compared with design object value, to confirm that this is anti- Hit whether part meets design requirement.

The advantageous effect of this method is compared with prior art：

1. the crashworthiness part emulation design method of the considerations of of the present invention shaping damage overcomes existing in the prior art It is follow-up imitative caused by ignoring part different parts shaping damage inherited characteristics during vehicle body high intensity crashworthiness part design of Simulation The problem of true computational accuracy deficiency and unreasonable structural design of fittings, forming temperature, shaping rate, friction etc. will be considered The factor that " shaping impairment value " after the part forming simulation of factor considers when being assessed as part crashworthiness, significantly improves The precision that subsequent simulation calculates, reduces the number changed repeatedly, it is ensured that the reasonability of structural design of fittings.

2. the considerations of of the present invention crashworthiness part emulation design method of shaping damage establishes the differing formed damage of boron steel Mechanics under wound value, different military service strain rates can be established using property database using the mechanics and examined using property database Consider the constitutive equation of differing formed damage and military service strain rate, which can accurately show the military service of material after shaping Energy.

3. the considerations of being established in the crashworthiness part emulation design method of the considerations of of the present invention shaping damage shaping damage The constitutive equation of wound and military service strain rate can be embedded into simulation analysis software, be set convenient for designer in the emulation of crashworthiness part Timing is called.Make designer that need not understand change procedure complicated during actual parts hot forming, it becomes possible to be imitated based on hot forming The shaping impairment value at each position of part carries out military service performance distribution after true analysis, ensures the credible of part subsequent simulation analysis result Degree, greatly reduces the difficulty of crashworthiness part design of Simulation and the requirement to designer.

Description of the drawings

The flow chart of the crashworthiness part emulation design method of the considerations of Fig. 1 is of the present invention shaping damage；

Step 1 establishes vehicle body height in the crashworthiness part emulation design method of the considerations of Fig. 2 is of the present invention shaping damage The schematic diagram that material at high temperature one directional tensile test uses device is carried out during intensity crashworthiness part hot forming damage criterion；

Step 1 establishes vehicle body height in the crashworthiness part emulation design method of the considerations of Fig. 3 is of the present invention shaping damage Test specimen schematic diagram used by progress material at high temperature one directional tensile test during intensity crashworthiness part hot forming damage criterion；

Step 1 establishes vehicle body height in the crashworthiness part emulation design method of the considerations of Fig. 4 is of the present invention shaping damage The schematic diagram of used knearest neighbour method during intensity crashworthiness part hot forming damage criterion；

Step 2 vehicle body high intensity in the crashworthiness part emulation design method of the considerations of Fig. 5 is of the present invention shaping damage The schematic diagram of model used when the hot forming of crashworthiness part is simulated；

Step 3 vehicle body is high-strength in the crashworthiness part emulation design method of the considerations of Fig. 6 a are of the present invention shaping damage Material at high temperature damages the schematic diagram of test specimen in virtual test when spending crashworthiness part crashworthiness Simulation Evaluation；

Step 3 vehicle body is high-strength in the crashworthiness part emulation design method of the considerations of Fig. 6 b are of the present invention shaping damage The schematic diagram of test specimen after being stretched when spending crashworthiness part crashworthiness Simulation Evaluation in material at high temperature damage virtual test；

Step 3 vehicle body is high-strength in the crashworthiness part emulation design method of the considerations of Fig. 7 a are of the present invention shaping damage Material at high temperature damages the schematic diagram of test specimen in actual tests when spending crashworthiness part crashworthiness Simulation Evaluation；

Step 3 vehicle body is high-strength in the crashworthiness part emulation design method of the considerations of Fig. 7 b are of the present invention shaping damage The schematic diagram of test specimen after being stretched when spending crashworthiness part crashworthiness Simulation Evaluation in material at high temperature damage actual tests；

Step 3 vehicle body high intensity in the crashworthiness part emulation design method of the considerations of Fig. 8 is of the present invention shaping damage The flow chart of material at high temperature damage test during crashworthiness part crashworthiness Simulation Evaluation；

Step 3 vehicle body high intensity in the crashworthiness part emulation design method of the considerations of Fig. 9 is of the present invention shaping damage The schematic diagram of material room temperature one directional tensile test neutron test specimen during crashworthiness part crashworthiness Simulation Evaluation；

Step 3 vehicle body is high-strength in the crashworthiness part emulation design method of the considerations of Figure 10 is of the present invention shaping damage Spend the virtual crushing test schematic diagram established during crashworthiness part crashworthiness Simulation Evaluation using Hypermesh softwares；

Step 3 vehicle body is high-strength in the crashworthiness part emulation design method of the considerations of Figure 11 is of the present invention shaping damage Spend the virtual bend test schematic diagram established during crashworthiness part crashworthiness Simulation Evaluation using Hypermesh softwares；

U-shaped in the crashworthiness part emulation design method specific embodiment of the considerations of Figure 12 is of the present invention shaping damage The structure diagram of section high-strength vehicle door collision prevention girders；

Figure 13 is that U-shaped section high-strength vehicle door collision prevention girders emulate when considered in specific embodiment with not considering shaping damage The comparison diagram of design method；

It is difficult to understand in the crashworthiness part emulation design method specific embodiment of the considerations of Figure 14 a are of the present invention shaping damage True stress and strain curve figure of the family name figure boron steel when temperature is 700 DEG C under different strain rate；

It is difficult to understand in the crashworthiness part emulation design method specific embodiment of the considerations of Figure 14 b are of the present invention shaping damage Family name figure boron steel is 0.1s in strain rate^-1When different temperatures under true stress and strain curve figure；

Boron in the crashworthiness part emulation design method specific embodiment of the considerations of Figure 15 is of the present invention shaping damage The specific heat capacity and the graph of the coefficient of heat conduction varied with temperature used by steel plate material；

Have in the crashworthiness part emulation design method specific embodiment of the considerations of Figure 16 is of the present invention shaping damage It in strain rate is 0.01s to have the geneva figure boron steels of different hot forming impairment values^-1When true stress and strain curve figure；

It is adopted in the crashworthiness part emulation design method specific embodiment of the considerations of Figure 17 is of the present invention shaping damage The U-shaped section high-strength vehicle door collision prevention girders obtained with Ls-dyna softwares generate schematic diagram during 60 ° of flexural deformation；

Figure 18 is to be considered in specific embodiment with not considering that the U-shaped section high-strength vehicle door collision prevention girders that shaping damages are virtual And the comparison diagram of force curve is contacted during actual flexion experiment；

Figure 19 is to be considered in specific embodiment with not considering that the U-shaped section high-strength vehicle door collision prevention girders that shaping damages are virtual And actual flexion test when energy absorption curve comparison diagram.

In figure：1.K type thermocouple wires, 2. test specimens, 3.CCD video cameras, 4. punch-pin, 5. blank holders, 6. plates, 7. cavity plates, 8. 9. sub- test specimen of test specimen after stretching, 10. rigid obstacles, 11. conquassation thin-walled crashworthiness parts；No. 12.1 rigidity circle rollings, 13. bendings are thin Wall crashworthiness part, No. 14.2 rigidity circle rollings, No. 15.3 rigidity circle rollings, 16.U tee section high-strength vehicle door collision prevention girders.

Specific embodiment

The present invention is explained in detail below in conjunction with the accompanying drawings：

Refering to Figure 12, using it is of the present invention the considerations of shaping damage crashworthiness part emulation design method and tradition do not examine The crashworthiness part emulation design method for considering shaping damage carries out design of Simulation to certain U-shaped section high-strength vehicle door collision prevention girders respectively, By by the case of two kinds, virtual test result during collision prevention girders crashworthiness Simulation Evaluation and actual tests result carry out pair Than verifying that the considerations of of the present invention shapes the validity of the crashworthiness part emulation design method of damage.Wherein, anticollision is used The nominal dimension of beam refers to Figure 13, wherein a=70mm, b=40mm, c=20mm, beam length 800mm, section thickness 2mm.

The particular content of situation one (considering shaping damage) is as follows：

Refering to Fig. 1, it is of the present invention the considerations of shaping damage crashworthiness part emulation design method include establish vehicle body height Intensity crashworthiness part hot forming damage criterion, vehicle body high intensity crashworthiness part hot forming simulation and vehicle body high intensity crashworthiness part resist It hits performance simulation and assesses three steps.

Step 1: establish vehicle body high intensity crashworthiness part hot forming damage criterion：

1) material at high temperature one directional tensile test

The high-temperature material characteristic of boron steel used, utilizes model during to understand actual production vehicle body high intensity crashworthiness part The hot modeling test machine of Gleeble3500 carries out a series of high temperature one directional tensile tests to boron steel test specimen, refering to Fig. 2, for ease of The deformation process of test specimen 2, finely tunes the holder part of the hot modeling test machine in shooting experiment, makes it with respect to original position It is rotated by 90 °, one end of K-type thermocouple wire 1 is welded in each examination by the concrete shape of test specimen 2 before testing refering to Fig. 3 using mash welder The center of 2 upper surface of part, the holding of 1 other end of K-type thermocouple wire freely discharges, for the temperature of Real-time Feedback test specimen 2 in experiment. First test specimen 2 is clamped in the fixture of hot modeling test machine in experiment, at the same one end that K-type thermocouple wire 1 is freely discharged with Hot modeling test machine is connected.Then, vacuumize process is carried out to hot modeling test machine inner space, it is real using resistance heating manner The heating process of existing test specimen 2, and then pass through the cooling velocity for the flow control test specimen 2 for adjusting compressed air, tool in cooling procedure Body testing program is as follows：

(1) 3min is kept the temperature after test specimen 2 being heated to 925 DEG C with the rate of heat addition of 5 DEG C/s, it is ensured that the microstructure of test specimen 2 Complete austenitizing；

(2) with the cooldown rate of 50 DEG C/s make test specimen 2 be down to successively 600 DEG C of deformation temperature, 700 DEG C, 800 DEG C, and each 5s is kept the temperature under deformation temperature makes 2 temperature of test specimen uniform and stable；

(3) in 600 DEG C, 700 DEG C, 800 DEG C of the deformation temperature and deformation strain rate 0.01s of setting^-1、0.1s^-1、1s^-1、 10s^-1Under test specimen 2 is stretched, test specimen 8 after obtained stretching is carried out until rupture failure, after fracture it is air-cooled, it is entire to stretch Thermal modeling test chance records the curve that load changes over time, temperature changes over time simultaneously in the process, and entire high temperature is unidirectional Tension test includes 12 groups of experimental conditions that 3 deformation temperatures and 4 deformation strain rates are combined into, and is respectively：Deformation temperature 600 DEG C and deformation strain rate 0.01s^-1, 600 DEG C of deformation temperature and deformation strain rate 0.1s^-1, 600 DEG C of deformation temperature and deformation strain Rate 1s^-1, 600 DEG C of deformation temperature and deformation strain rate 10s^-1, 700 DEG C of deformation temperature and deformation strain rate 0.01s^-1, deformation temperature 700 DEG C and deformation strain rate 0.1s^-1, 700 DEG C of deformation temperature and deformation strain rate 1s^-1, 700 DEG C of deformation temperature and deformation strain Rate 10s^-1, 800 DEG C of deformation temperature and deformation strain rate 0.01s^-1, 800 DEG C of deformation temperature and deformation strain rate 0.1s^-1, deformation temperature 800 DEG C of degree and deformation strain rate 1s^-1, 800 DEG C of deformation temperature and deformation strain rate 10s^-1, carry out once under every group of experimental condition High temperature tension test changes the curve F (t) that the load that hot modeling test machine in experiment measures changes over time according to formula (1) Calculate the curve σ changed over time for the nominal stress of test specimen 2_nom(t), the gauge length segment length of the test specimen 2 CCD camera 3 measured The curve Δ L (t) changed over time is scaled the curve that the gauge length section apparent strain of test specimen 2 changes over time according to formula (2) ε_nom(t), the curve σ changed over time the nominal stress of test specimen 2 according to formula (3)_nom(t) it is scaled really should for test specimen 2 The curve σ that power changes over time_true(t), the curve changed over time the gauge length section apparent strain of test specimen 2 according to formula (4) ε_nom(t) it is scaled the curve ε that the gauge length section logarithmic strain of test specimen 2 changes over time_true(t), and eliminate two curves in time Variable t, with logarithmic strain ε_trueFor independent variable, true stress σ_trueFor dependent variable, really should under each experimental condition is obtained Force-strain curve σ_true(ε_true)：

In formula：F (t) is the curve that load changes over time；A₀For specimen equidistance line marking section original cross-sectional area；σ_nom(t) it is examination The curve that the nominal stress of part changes over time.

In formula：Δ L (t) is the curve that the gauge length segment length of test specimen changes over time；L₀For specimen equidistance line marking section original length； ε_nom(t) curve changed over time for the gauge length section apparent strain of test specimen.

σ_true(t)=σ_nom(t)(1+ε_nom(t)) (3)

In formula：σ_nom(t) curve changed over time for the nominal stress of test specimen；ε_nom(t) it is the gauge length section name of test specimen Strain the curve changed over time；σ_true(t) curve changed over time for the true stress of test specimen.

ε_true(t)=ln (1+ ε_nom(t)) (4)

In formula：ε_nom(t) curve changed over time for the gauge length section apparent strain of test specimen；ε_true(t) it is the gauge length of test specimen The curve that section logarithmic strain changes over time.

2) constitutive equation based on shaping damage is established

(1) failure procedure of metal material is the forming core of material internal defect (Micro-v oid and micro-crack), grows up, is coupled shape Into macroscopic cracking.This process is usually defined as to the damage of material, when damage reaches certain level, material can not continue Carrying.Material microcosmic degeneration during in order to consider shaping in simulation analysis, many scholars establish a series of visco-plasticity damages Constitutive equation, by introducing damage factor, the phenomenon that simulating many and time correlation, such as：Creep, recrystallization, reply etc..Root According to methods of the Lin when scholars derive deformation of creep constitutive equation, the constitutive equation based on shaping damage is established in the present invention, with Consider the damage of material during hot forming, expression is as follows：

In formula：Equivalent plastic strain rate when being shaping；σ_eEquivalent stress when being shaping；By dislocation when H is shaping Caused strain hardening；Shape damage variable f_d1, excursion is 0~1, f_d1Represent that material does not damage during shaping when=0 Wound, f_d1Represent that material is entirely ineffective during shaping when=1；Plastic strain rate component during to shape；S_ijPartially should during to shape Force component；ρ_iFor the dislocation density under material original state, ρ_mMaterial accessible maximum during to shape Dislocation density, and ρ_i≤ρ≤ρ_m, i.e.,σ_ijStress tensor component when being shaping；Overall strain when being shaping Measure component；Plastic strain component of tensor when being shaping；D_ijklIt is quadravalence Stiffness Tensor component；E is Young's modulus；υ is pool Loose ratio；δ_ijFor the Kronecker factor, subscript i, j, k, l excursion are 1~3, repeat subscript and follow Einstein's summation convention.

Parameter k, K, n₁, B, C, D, E be with the relevant material parameter of temperature, be defined as follows：

K=k₀exp(Q_k/RT) (12)

K=K₀exp(Q_K/RT) (13)

n₁=n₁₀exp(Q_n/RT) (14)

B=B₀exp(Q_B/RT) (15)

C=C₀exp(-Q_C/RT) (16)

D=D₀exp(Q_D/RT) (17)

E=E₀exp(Q_E/RT) (18)

In formula：R is universal gas constant；T is temperature；Q is activation energy.

(2) material parameter in constitutive equation is determined

Definitely to describe the relation under material at high temperature between stress-strain, it is thus necessary to determine that in shaping damage Constitutive Equation Material parameter, therefore using advanced planning algorithm to true under each experimental condition for being obtained in material at high temperature one directional tensile test Real load-deformation curve is fitted.First, the object function of Solve problems is established, then evolves and advises to object function application Cost-effective method optimizes, so as to finally determine the material parameter in constitutive equation.Here, it is thus necessary to determine that material parameter it is a total of It 20, is followed successively by：A、n₂、γ₁、γ₂、k₀、n₀、K₀、n₁₀、B₀、C₀、D₀、E₀、Q_k、Q_K、Q_n、Q_B、Q_C、Q_D、Q_E、R。

Similar to the knearest neighbour method (refer to Fig. 4) that Li et al. people proposes, according between matched curve and test data away from From establishing object function：

In formula：F (x) is to form vector x=(A, n on 20 unknown material parameters₂,...,Q_E, R) real-valued function； N is the total capacity of test data；w_iFor the weighted value of the i-th data point；Respectively i-th of test data is corresponding should Power and strain value；Respectively with the stress and strain value in the corresponding matched curve of i-th of test dataIt is restrained for matched curve is made to strain section to test data, it willF (x) is added in obtain It arrives：

In formula：W is weight coefficient.

To reduce the difficulty of definite weighted value in actual use and overcoming the problems, such as that ess-strain unit is inconsistent, join That examines Lin et al. propositions improves target without what unit distance method and adaptive weighting factorization method and Cao et al. proposed with logarithm method The optimal speed of function, the object function finally established are as follows：

In formula：

The object function of foundation is optimized using Yao et al. improved tachytelic evolution planning algorithms proposed, is determined All material parameter.The algorithm is theoretical according to Darwinian natural selection and Mendelian hereditary variation, and biological evolution is to pass through 4 breeding, variation, competition, selection citation forms are realized.Similarly, Evolutionary Programming Algorithm is using object function as biological species Group, by mutation, selection generates population of new generation；Repeat this process, until obtain the population that meets the requirements or it is defined into Change the time limit.Detailed evolutional programming is the process of an iteration：

[1] iteration count k=1 is taken, generates μ population at random, i.e. stochastic inputs μ groups vector is to (x_i,η_i), whereinη_iFor evolutional programming adaptive strategy parameter, i=1,2,3 ..., μ；

[2] for each individual vector to (x_i,η_i), calculate f (x_i)；

[3] for each parent vector to (x_i,η_i), generate two filial generation vectors pairWithWherein：

It calculates and comparesWithSize, both take the vector pair corresponding to smaller, be denoted as (x_i', η_i').Wherein x_i(j), x_i' (j), η_i(j), η_i' (j) be respectively vector x_i, x_i', η_i, η_i' j-th of component (j=1,2 ..., N, n are the number of material parameter to be optimized)；N (0,1) is the random number for obeying one-dimensional standardized normal distribution；N_j(0,1) it is obedience One-dimensional standardized normal distribution corresponds to the random number of j-th of component；δ_jCorrespond to the random of j-th component to obey Cauchy's distribution Number；Parameter τ¹It is taken respectively with τWithStandardized normal distribution and the density function of Cauchy's distribution are respectively：

[4] for all i=1,2,3 ..., μ, by all parent vectors to (x_i,η_i) and filial generation vector to (x_i', η_i') as an entirety, take out q vector pair.Then, by all parents and any one vector pair of filial generation vector centering The q vector with taking-up compares vector to corresponding target function value, if the vector is to being less than q vector to making comparisons Some of centering, then the vector add 1 to score (top score of all vectors pair be q, minimum to be scored at 0)；

[5] μ vector pair of highest scoring, the parent vector pair as next iteration are selected from 2 μ vectors pair；

[6] judge whether iteration termination condition meets；It is such as unsatisfactory for, then k=k+1, and repeats the above process.

Finally, definite material parameter is：A=5.223, n₂=1.54, γ₁=3.1, γ₂=17.4, k₀= 12.4MPa、n₀=0.4, K₀=30MPa, n₁₀=0.0067, B₀=80MPa, C₀=55500, D₀=1.38e^-4、E₀= 1100MPa、Q_k=8400J/mol, Q_K=8400J/mol, Q_n=50000J/mol, Q_B=8400J/mol, Q_C=99900J/ mol、Q_D=10648J/mol, Q_E=17500J/mol, R=8.3J/mol.

(3) software of damage Constitutive Equation is realized

The shaping damage Constitutive Equation for having determined that material parameter is written as Ls-dyna user certainly using Fortran language Definition material subprogram is embedded by User Defined material subprogram interface in finite element software Ls-dyna.Figure 14-a are True stress and strain curve of the austenite state boron steel at 700 DEG C under different strain rate is 0.01s including strain rate^-1When examination It is 1s to test data and matched curve and strain rate^-1When test data and matched curve, and Figure 14-b be austenite state boron steel In 0.1s^-1When different temperatures under true stress and strain curve, including temperature be 800 DEG C when test data and matched curve And temperature be 600 DEG C when test data and matched curve.

Step 2: the high-strength vehicle door collision prevention girders hot forming of U-shaped section is simulated：

1) refering to Fig. 5, establish the high-strength vehicle door collision prevention girders hot forming of U-shaped section using Hypermesh finite element softwares and imitate True mode, the object in model include plate 6, punch-pin 4, cavity plate 7 and blank holder 5；

2) it is respectively each object imparting section attribute and material property in model, all objects are using shell unit section Attribute * SECTION_SHELL, the thickness t of each object are followed successively by：T1=2mm, t2=t3=t4=5mm, wherein t1 are plate Thickness；T2 is the thickness of punch-pin；T3 is the thickness of cavity plate；T4 is the thickness of blank holder.And punch-pin 4, cavity plate 7 and blank holder 5 are adopted With rigid body physical material * MAT_RIGID, the density p of each object is followed successively by：ρ 2=ρ 3=ρ 4=7830kg/m³, wherein ρ 2 is convex The density of mould；ρ 3 is the density of cavity plate；ρ 4 is the density of blank holder.Elastic modulus E is followed successively by：E2=E3=E4=210GPa, Wherein E2 is the elasticity modulus of punch-pin；E3 is the elasticity modulus of cavity plate；E4 is the elasticity modulus of blank holder.Poisson's ratio υ is followed successively by： υ 2=υ 3=υ 4=0.3, wherein υ 2 are the Poisson's ratio of punch-pin；υ 3 is the Poisson's ratio of cavity plate；υ 4 is the Poisson's ratio of blank holder.And plate Material 6 is then using the above-mentioned User Defined physical material based on shaping damage, and all objects use isotropism hot material * MAT_THERMAL_ISOTROPIC, the specific heat capacity HC of each object are followed successively by：HC2=HC3=HC4=500J/ (kgK), wherein HC2 is the specific heat capacity of punch-pin；HC3 is the specific heat capacity of cavity plate；HC4 is the specific heat capacity of blank holder.Coefficient of heat conduction TC is followed successively by： TC2=TC3=TC4=50W/ (mK), wherein TC2 are the coefficient of heat conduction of punch-pin；HC3 is the coefficient of heat conduction of cavity plate；HC4 For the coefficient of heat conduction of blank holder.And the specific heat capacity HC and coefficient of heat conduction TC of plate 6 refer to Figure 15；

3) contact relation in model between each object is set, defines boundary condition (temperature field that has, the movement of each object Characteristic, constraints) and model calculate needed for control card；

4) U-shaped section high-strength vehicle door collision prevention girders hot forming simulation model is solved using Ls-dyna softwares, after obtaining shaping Part model and its shaping damage cloud atlas and thickness distribution cloud atlas.

Step 3: U-shaped section high-strength vehicle door collision prevention girders crashworthiness Simulation Evaluation

1) mechanics uses property database

(1) material at high temperature damage test

Refering to Fig. 6, virtual test is carried out to test specimen 2 shown in Fig. 3 using Ls-dyna softwares, entire test specimen 2 uses shell list First section attribute * SECTION_SHELL, thickness t=2mm, the User Defined physical material damaged using consideration shaping, And Figure 15 is referred to using isotropism hot material * MAT_THERMAL_ISOTROPIC, specific heat capacity HC and coefficient of heat conduction TC. Meanwhile define l in 2 intermediate region of test specimen₀The equal temperature section of=25mm long applies steady temperature field in the section, and in the Duan Zuo Right two side areas then applies corresponding temperature field according to 2 Temperature Distribution of test specimen in actual tests.During virtual test, test specimen 2 is constrained All 6 degree of freedom of left end node, in the forced displacement that right end application changes over time vertically, it is ensured that equal temperature section is with constant Strain rate deformed.Equal temperature section is made to take typical experimental condition in experiment：750 DEG C of forming temperature, deformation strain rate 0.1s^-1.Under this condition, a series of virtual tests are carried out, the shaping impairment value of unit in equal temperature section is made to respectively reach target shaping damage Wound value 0,0.05,0.1,0.2,0.6 is divided to get test specimen 8 after a series of stretching to equal temperature sections with differing formed impairment value The changing value 0 of each 2 samming segment length of test specimen, Δ l are not measured_0.05,Δl_0.1,Δl_0.2,Δl_0.6。

Refering to Fig. 7, actual tests are carried out to test specimen 2 shown in Fig. 3 using Gleeble hot modeling test machines, experimental condition with Virtual test is identical.It is shot in experiment using CCD camera 3, and passes through the examination of ARAMIS optical skew systems Real-time Feedback The deflection of 2 equal temperature section of part respectively reaches 0, Δ l when each 2 samming segment length of test specimen changes_0.05,Δl_0.1,Δl_0.2,Δl_0.6 When, stop stretching (same samming segment length changing value is repeated 3 times experiment), at this point, material reaches at equal temperature section in actual tests With equal degree of injury in virtual test.Then, each 2 equal temperature section rapid quenching of test specimen is cooled to room temperature to get to a series of Test specimen 8 after the stretching of martensitic phase after equal quenching of the temperature section with differing formed impairment value, entire material at high temperature damage test Flow refers to Fig. 8.

(2) test specimen is processed

Linear cutter is carried out to test specimen 8 after a series of quenched stretchings for being obtained in material at high temperature damage test, is obtained To for sub- test specimen 9 used in material room temperature one directional tensile test, refering to Fig. 9 bold portions.Then, with fine sandpaper to all sub- examinations 9 each surface of part is slightly polished, and removes oxide skin above, and records the smallest cross-sectional of each sub- 9 gauge length section of test specimen after polishing Product, the original cross-sectional area A as 9 gauge length section of materials described below room temperature one directional tensile test neutron test specimen₀。

(3) material room temperature one directional tensile test

There is the son of different impairment values using electronic universal tester to the equal temperature section obtained in material at high temperature damage test Test specimen 9 carries out 3 kinds of different military service strain rates and (is followed successively by 0.01s^-1、1s^-1、10s^-1) one directional tensile test, all sub- test specimens 9 It stretches at room temperature until fracture.The curve F (t) that chance record load changes over time is tested in entire drawing process, and It is scaled the curve σ that the nominal stress of sub- test specimen 9 changes over time according to formula (1)_nom(t), use and stretch extensometer The curve Δ L (t) that the gauge length segment length of sub- test specimen 9 changes over time can be measured, and it is scaled sub- test specimen according to formula (2) The curve ε that 9 gauge length section apparent strain changes over time_nom(t), according to formula (3) by the nominal stress of sub- test specimen 9 at any time The curve σ of variation_nom(t) it is scaled the curve σ that the true stress of sub- test specimen 9 changes over time_trueIt (t), will according to formula (4) The curve ε that the gauge length section apparent strain of sub- test specimen 9 changes over time_nom(t) be scaled the gauge length section logarithmic strain of sub- test specimen 9 with The curve ε of time change_true(t), and the time variable t in two curves is eliminated, with logarithmic strain ε_trueFor independent variable, really should Power σ_trueFor dependent variable, the true stress and strain curve σ of each sub- test specimen 9 is obtained_true(ε_true).Finally, obtain with 5 kinds of differences Shape impairment value, 3 kinds of different military service strain rates sub- test specimen 9 true stress and strain curve σ_true(ε_true), under foundation State the military service constitutive equation for considering shaping damage.

2) the military service constitutive equation for considering shaping damage is established

For in vehicle body crashworthiness part virtual test, consider part forming damage and military service strain rate is on active service to it performance It influences, now establishes the military service constitutive equation for considering shaping damage, expression is as follows：

In formula：It is equivalent plastic strain rate when being on active service；σ is equivalent stress when being on active service；Military service damage variable f_d2, Excursion is 0~1, f_d2Material is not on active service damage when representing to be on active service when=0, f_d2Material loses completely when representing to be on active service when=1 Effect；Plastic strain rate component during to be on active service；S_s-ijDeviatoric stress component during to be on active service；ρ_siFor The dislocation density of material, ρ before military service_smMaterial accessible maximum dislocation density during to be on active service, and ρ_si≤ρ_s≤ρ_sm, i.e.,σ_s-ijIt is stress tensor component when being on active service；It is overall strain component of tensor when being on active service；It is modeling when being on active service Property strain tensor component；D_s-ijklIt is quadravalence Stiffness Tensor component；L is Young's modulus；υ is Poisson's ratio；δ_ijFor Kronecker because Son, subscript i, j, k, l excursion are 1~3, repeat subscript and follow Einstein's summation convention.

Parameter y, Y, F, G, L, β₁、β₂、β₃、γ₅、γ₆It is to damage relevant material parameter with shaping, is defined as follows：

Y=y₀exp(W_y/f_d1) (33)

Y=Y₀exp(W_Y/f_d1) (34)

F=F₀exp(W_F/f_d1) (35)

G=G₀exp(-W_G/f_d1) (36)

L=L₀exp(W_L/f_d1) (37)

Used in the definite military service Material Parameter in Constitutive Equation for considering shaping damage and the realization of military service constitutive equation software Method used is identical when method is with establishing based on shaping damage Constitutive Equation, and here, it is thus necessary to determine that material parameter A total of 25, and 25 material parameters finally determined, it is followed successively by：Z=6.32, γ₃=4.6, γ₄=2.67, γ₇= 30.4、n_c=0.4, y₀=30.3MPa, Y₀=60MPa, F₀=40MPa, G₀=4000, L₀=4800MPa, β₁₀=1.2, β₂₀= 3.5、β₃₀=1.4, γ₅₀=0.6, γ₆₀=5.9, W_y=740, W_Y=600, W_F=1200, W_G=990, W_L=670, Figure 16 is with different hot forming impairment values Geneva figure boron steel is 0.01s in strain rate^-1When true stress and strain curve figure, including hot forming impairment value be 0.05 when Test data and matched curve when being 0.2 of test data and matched curve and hot forming impairment value.

3) U-shaped section high-strength vehicle door collision prevention girders virtual test

With reference to standard GB/T/T 7314-2005 and GB/T 232-2010, sent out according to vehicle body high intensity crashworthiness part Role carries out it virtual crushing test or virtual bend test during raw collision (refering to Figure 10 and Figure 11).Refering to figure 17, because door anti-collision joist is primarily subjected to bending load in side impact, therefore virtual bend test is carried out to it, virtual test process is such as Under：

(1) U-shaped section high-strength vehicle door collision prevention girders virtual test model is established using Hypermesh softwares, in model Object includes：No. 1 rigidity circle rolling 12, the rigidity circle rolling 15 of rigidity circle rolling 14,3 of U-shaped section high-strength vehicle door collision prevention girders 16,2；

(2) it is respectively each object imparting section attribute and material property in model, all objects are using shell unit section Face attribute * SECTION_SHELL, the thickness of all rigidity circle rollings is t=5mm, after the thickness distribution succession hot forming of collision prevention girders The thickness distribution of part.All rigidity circle rollings are using rigid body physical material * MAT_RIGID, density p=7830kg/m³, bullet Property modulus E=210GPa and Poisson's ratio υ=0.3, and collision prevention girders are then on active service this structure using the User Defined for considering shaping damage Physical material；

(3) contact relation in model between each object is set, defines boundary condition (kinetic characteristic, the constraint item of each object Part) and model calculate needed for control card；

(4) U-shaped section high-strength vehicle door collision prevention girders virtual test model is solved using Ls-dyna softwares, exports collision prevention girders Deformation tendency cloud atlas, contact force curve and the energy absorption curve changed over time, and compared with design object value, to confirm Whether the U-shaped section high-strength vehicle door collision prevention girders 16 meet design requirement.

The particular content of situation two (not considering shaping damage) is as follows：

Tradition do not consider shaping damage crashworthiness part emulation design method only include vehicle body high intensity crashworthiness part heat into Shape is simulated and vehicle body high intensity crashworthiness part crashworthiness two steps of Simulation Evaluation.

The first step, U-shaped section high-strength vehicle door collision prevention girders hot forming simulation

1) refering to Fig. 5, establish the high-strength vehicle door collision prevention girders hot forming of U-shaped section using Hypermesh finite element softwares and imitate True mode, the object in model include plate 6, punch-pin 4, cavity plate 7 and blank holder 5；

2) it is respectively each object imparting section attribute and material property in model, all objects are using shell unit section Attribute * SECTION_SHELL, the thickness t of each object are followed successively by：T1=2mm, t2=t3=t4=5mm, wherein t1 are plate Thickness；T2 is the thickness of punch-pin；T3 is the thickness of cavity plate；T4 is the thickness of blank holder.And punch-pin 4, cavity plate 7 and blank holder 5 are adopted With rigid body physical material * MAT_RIGID, the density p of each object is followed successively by：ρ 2=ρ 3=ρ 4=7830kg/m³, wherein ρ 2 is convex The density of mould；ρ 3 is the density of cavity plate；ρ 4 is the density of blank holder.Elastic modulus E is followed successively by：E2=E3=E4=210GPa, Wherein E2 is the elasticity modulus of punch-pin；E3 is the elasticity modulus of cavity plate；E4 is the elasticity modulus of blank holder.Poisson's ratio υ is followed successively by： υ 2=υ 3=υ 4=0.3, wherein υ 2 are the Poisson's ratio of punch-pin；υ 3 is the Poisson's ratio of cavity plate；υ 4 is the Poisson's ratio of blank holder.And plate Material 6 is close then using bullets being affected by temperature-viscous-plasticity physical material * MAT_ELASTIC_VISCOPLASTIC_THERMAL Spend ρ=7830kg/m³, elastic modulus E=210GPa, Poisson's ratio υ=0.3, yield strength SIGY=700MPa and thermal expansion system Number ALPHA=1.3e^-5/ K, and all objects are using isotropism hot material * MAT_THERMAL_ISOTROPIC, each object Specific heat capacity HC be followed successively by：HC2=HC3=HC4=500J/ (kgK), wherein HC2 are the specific heat capacity of punch-pin；HC3 is cavity plate Specific heat capacity；HC4 is the specific heat capacity of blank holder.Coefficient of heat conduction TC is followed successively by：TC2=TC3=TC4=50W/ (mK), Middle TC2 is the coefficient of heat conduction of punch-pin；HC3 is the coefficient of heat conduction of cavity plate；HC4 is the coefficient of heat conduction of blank holder.And plate 6 Specific heat capacity HC and coefficient of heat conduction TC refer to Figure 15；

3) contact relation in model between each object is set, defines boundary condition (temperature field that has, the movement of each object Characteristic, constraints) and model calculate needed for control card；

4) U-shaped section high-strength vehicle door collision prevention girders hot forming simulation model is solved using Ls-dyna softwares, after obtaining shaping Part model and its thickness distribution cloud atlas.

Second step, U-shaped section high-strength vehicle door collision prevention girders crashworthiness Simulation Evaluation

Refering to Figure 17, because door anti-collision joist is primarily subjected to bending load in side impact, therefore virtual bend test is carried out to it, Virtual test process is as follows：

(1) U-shaped section high-strength vehicle door collision prevention girders virtual test model is established using Hypermesh softwares, in model Object includes：No. 1 rigidity circle rolling 12, the rigidity circle rolling 15 of rigidity circle rolling 14,3 of U-shaped section high-strength vehicle door collision prevention girders 16,2；

(2) it is respectively each object imparting section attribute and material property in model, all objects are using shell unit section Face attribute * SECTION_SHELL, the thickness of all rigidity circle rollings is t=5mm, after the thickness distribution succession hot forming of collision prevention girders The thickness distribution of part.All rigidity circle rollings are using rigid body physical material * MAT_RIGID, density p=7830kg/m³, bullet Property modulus E=210GPa and Poisson's ratio υ=0.3, and collision prevention girders are then using under the different military service strain rates for not considering shaping damage Preferable martensitic phase material；

(3) contact relation in model between each object is set, defines boundary condition (kinetic characteristic, the constraint item of each object Part) and model calculate needed for control card；

(4) U-shaped section high-strength vehicle door collision prevention girders virtual test model is solved using Ls-dyna softwares, exports collision prevention girders Deformation tendency cloud atlas, contact force curve and the energy absorption curve changed over time, and compared with design object value, to confirm Whether the U-shaped section high-strength vehicle door collision prevention girders 16 meet design object requirement.

Experimental test

It is closed according to the contact between each object defined in the 16 hot forming analog portion of U-shaped section high-strength vehicle door collision prevention girders System, the temperature field of each object, kinetic characteristic, constraints carry out actual hot forming processing, and high-strength to the U-shaped section after shaping It spends door anti-collision joist 16 and carries out actual flexion experiment, obtain contact force and energy absorption curve that it is changed over time.

All include in Figure 18 and Figure 19 and do not consider to shape damage simulation result, consider shaping damage simulation result and experiment As a result, 16 contact force of U-shaped section high-strength vehicle door collision prevention girders and suction by the way that virtual bend test in the case of two kinds is obtained 16 contact force of U-shaped section high-strength vehicle door collision prevention girders and energy absorption curve that energy curve is obtained with actual flexion experiment carry out It compares, finds to consider that 16 contact force of U-shaped section high-strength vehicle door collision prevention girders of shaping damage and energy absorption curve and reality are curved The result that song experiment obtains is closer.

Therefore, can using it is of the present invention the considerations of shaping damage crashworthiness part emulation design method to carry out vehicle body high Crashworthiness assessment after intensity crashworthiness part forming simulation, hot forming damage is taken into account, improves commenting for its crashworthiness Estimate precision, enhancing vehicle body high intensity crashworthiness part design of Simulation is to the directive significance of actual design so that the vehicle body of actual design High intensity crashworthiness part more easily reachs design object requirement, so as to reduce test number (TN), shortens the construction cycle, reduce exploitation into This.

Claims (1)

1. consider the crashworthiness part emulation design method of shaping damage, it is characterised in that step is as follows：

Step 1: establishing vehicle body high intensity crashworthiness part hot forming damage criterion, detailed process is：

1) material at high temperature one directional tensile test

A series of high temperature one directional tensile tests are carried out to boron steel test specimen using hot modeling test machine, mash welder is utilized before testing by K One end of type thermocouple wire (1) is welded in the center of each test specimen (2) upper surface, and the holding of K-type thermocouple wire (1) other end is freely released It puts, first test specimen (2) is clamped in the fixture of hot modeling test machine in experiment, while K-type thermocouple wire (1) is freely discharged One end is connected with hot modeling test machine, then, carries out vacuumize process to hot modeling test machine inner space, utilizes resistance heating Mode realizes the heating process of test specimen (2), and in cooling procedure then by adjust compressed air flow control test specimen (2) it is cold But speed, specific testing program are as follows：

(1) 3min is kept the temperature after test specimen (2) being heated to 925 DEG C with the rate of heat addition of 5 DEG C/s, it is ensured that the microstructure of test specimen (2) Complete austenitizing；

(2) with the cooldown rate of 50 DEG C/s make test specimen (2) be down to successively 600 DEG C of deformation temperature, 700 DEG C, 800 DEG C, and in each change 5s is kept the temperature at a temperature of shape makes test specimen (2) temperature uniform and stable；

(3) in 600 DEG C, 700 DEG C, 800 DEG C of the deformation temperature and deformation strain rate 0.01s of setting^-1、0.1s^-1、1s^-1、10s^-1Under Test specimen (2) is stretched, test specimen (8) after obtained stretching is carried out until rupture failure, after fracture air-cooled, was entirely stretched Thermal modeling test chance records the curve that load changes over time, temperature changes over time simultaneously in journey, and entire high temperature is unidirectionally drawn 12 groups of experimental conditions that experiment is combined into comprising 3 deformation temperatures and 4 deformation strain rates are stretched, are respectively：600 DEG C of deformation temperature With deformation strain rate 0.01s^-1, 600 DEG C of deformation temperature and deformation strain rate 0.1s^-1, 600 DEG C of deformation temperature and deformation strain rate 1s^-1, 600 DEG C of deformation temperature and deformation strain rate 10s^-1, 700 DEG C of deformation temperature and deformation strain rate 0.01s^-1, deformation temperature 700 DEG C and deformation strain rate 0.1s^-1, 700 DEG C of deformation temperature and deformation strain rate 1s^-1, 700 DEG C of deformation temperature and deformation strain Rate 10s^-1, 800 DEG C of deformation temperature and deformation strain rate 0.01s^-1, 800 DEG C of deformation temperature and deformation strain rate 0.1s^-1, deformation temperature 800 DEG C of degree and deformation strain rate 1s^-1, 800 DEG C of deformation temperature and deformation strain rate 10s^-1, carry out once under every group of experimental condition High temperature tension test changes the curve F (t) that the load that hot modeling test machine in experiment measures changes over time according to formula (1) Calculate the curve σ changed over time for the nominal stress of test specimen (2)_nom(t), the gauge length of the test specimen (2) CCD camera (3) measured The gauge length section apparent strain that the curve Δ L (t) that segment length changes over time is scaled test specimen (2) according to formula (2) becomes at any time The curve ε of change_nom(t), the curve σ changed over time the nominal stress of test specimen (2) according to formula (3)_nom(t) it is scaled test specimen (2) the curve σ that true stress changes over time_true(t), according to formula (4) by the gauge length section apparent strain of test specimen (2) at any time Between the curve ε that changes_nom(t) it is scaled the curve ε that the gauge length section logarithmic strain of test specimen (2) changes over time_true(t), and eliminate Time variable t in two curves, with logarithmic strain ε_trueFor independent variable, true stress σ_trueFor dependent variable, each test bar is obtained True stress and strain curve σ under part_true(ε_true)：

<mrow> <msub> <mi>&amp;sigma;</mi> <mrow> <mi>n</mi> <mi>o</mi> <mi>m</mi> </mrow> </msub> <mrow> <mo>(</mo> <mi>t</mi> <mo>)</mo> </mrow> <mo>=</mo> <mfrac> <mrow> <mi>F</mi> <mrow> <mo>(</mo> <mi>t</mi> <mo>)</mo> </mrow> </mrow> <msub> <mi>A</mi> <mn>0</mn> </msub> </mfrac> <mo>-</mo> <mo>-</mo> <mo>-</mo> <mrow> <mo>(</mo> <mn>1</mn> <mo>)</mo> </mrow> </mrow>

In formula：F (t) is the curve that load changes over time；A₀For specimen equidistance line marking section original cross-sectional area；σ_nom(t) it is test specimen The curve that nominal stress changes over time；

<mrow> <msub> <mi>&amp;epsiv;</mi> <mrow> <mi>n</mi> <mi>o</mi> <mi>m</mi> </mrow> </msub> <mrow> <mo>(</mo> <mi>t</mi> <mo>)</mo> </mrow> <mo>=</mo> <mfrac> <mrow> <mi>&amp;Delta;</mi> <mi>L</mi> <mrow> <mo>(</mo> <mi>t</mi> <mo>)</mo> </mrow> </mrow> <msub> <mi>L</mi> <mn>0</mn> </msub> </mfrac> <mo>-</mo> <mo>-</mo> <mo>-</mo> <mrow> <mo>(</mo> <mn>2</mn> <mo>)</mo> </mrow> </mrow>

In formula：Δ L (t) is the curve that the gauge length segment length of test specimen changes over time；L₀For specimen equidistance line marking section original length；ε_nom (t) curve changed over time for the gauge length section apparent strain of test specimen；

σ_true(t)=σ_nom(t)(1+ε_nom(t)) (3)

In formula：σ_nom(t) curve changed over time for the nominal stress of test specimen；ε_nom(t) it is the gauge length section apparent strain of test specimen The curve changed over time；σ_true(t) curve changed over time for the true stress of test specimen；

ε_true(t)=ln (1+ ε_nom(t)) (4)

In formula：ε_nom(t) curve changed over time for the gauge length section apparent strain of test specimen；ε_true(t) it is the gauge length Duan Zhen of test specimen The curve changed over time is strained in fact；

2) constitutive equation based on shaping damage is established：

(1) constitutive equation based on shaping damage is established, the damage of material, expression are as follows during considering hot forming：

<mrow> <msubsup> <mover> <mi>&amp;epsiv;</mi> <mo>&amp;CenterDot;</mo> </mover> <mi>e</mi> <mi>P</mi> </msubsup> <mo>=</mo> <msup> <mrow> <mo>(</mo> <mfrac> <mrow> <msub> <mi>&amp;sigma;</mi> <mi>e</mi> </msub> <mo>/</mo> <mrow> <mo>(</mo> <mn>1</mn> <mo>-</mo> <msub> <mi>f</mi> <mrow> <mi>d</mi> <mn>1</mn> </mrow> </msub> <mo>)</mo> </mrow> <mo>-</mo> <mi>H</mi> <mo>-</mo> <mi>z</mi> </mrow> <mi>K</mi> </mfrac> <mo>)</mo> </mrow> <msub> <mi>n</mi> <mn>1</mn> </msub> </msup> <msup> <mrow> <mo>(</mo> <mn>1</mn> <mo>-</mo> <msub> <mi>f</mi> <mrow> <mi>d</mi> <mn>1</mn> </mrow> </msub> <mo>)</mo> </mrow> <mrow> <mo>-</mo> <msub> <mi>&amp;gamma;</mi> <mn>1</mn> </msub> </mrow> </msup> <mo>-</mo> <mo>-</mo> <mo>-</mo> <mrow> <mo>(</mo> <mn>5</mn> <mo>)</mo> </mrow> </mrow>

<mrow> <msubsup> <mover> <mi>&amp;epsiv;</mi> <mo>&amp;CenterDot;</mo> </mover> <mrow> <mi>i</mi> <mi>j</mi> </mrow> <mi>P</mi> </msubsup> <mo>=</mo> <mfrac> <mrow> <mn>3</mn> <msub> <mi>S</mi> <mrow> <mi>i</mi> <mi>j</mi> </mrow> </msub> </mrow> <mrow> <mn>2</mn> <msub> <mi>&amp;sigma;</mi> <mi>e</mi> </msub> </mrow> </mfrac> <msubsup> <mover> <mi>&amp;epsiv;</mi> <mo>&amp;CenterDot;</mo> </mover> <mi>e</mi> <mi>P</mi> </msubsup> <mo>-</mo> <mo>-</mo> <mo>-</mo> <mrow> <mo>(</mo> <mn>6</mn> <mo>)</mo> </mrow> </mrow>

<mrow> <mover> <mover> <mi>&amp;rho;</mi> <mo>&amp;OverBar;</mo> </mover> <mo>&amp;CenterDot;</mo> </mover> <mo>=</mo> <mi>A</mi> <mrow> <mo>(</mo> <mn>1</mn> <mo>-</mo> <mover> <mi>&amp;rho;</mi> <mo>&amp;OverBar;</mo> </mover> <mo>)</mo> </mrow> <mo>|</mo> <msubsup> <mover> <mi>&amp;epsiv;</mi> <mo>&amp;CenterDot;</mo> </mover> <mi>e</mi> <mi>P</mi> </msubsup> <mo>|</mo> <mo>-</mo> <mi>C</mi> <msup> <mover> <mi>&amp;rho;</mi> <mo>&amp;OverBar;</mo> </mover> <msub> <mi>n</mi> <mn>2</mn> </msub> </msup> <mo>-</mo> <mo>-</mo> <mo>-</mo> <mrow> <mo>(</mo> <mn>7</mn> <mo>)</mo> </mrow> </mrow>

<mrow> <mi>H</mi> <mo>=</mo> <mi>B</mi> <msup> <mover> <mi>&amp;rho;</mi> <mo>&amp;OverBar;</mo> </mover> <msub> <mi>n</mi> <mn>0</mn> </msub> </msup> <mo>-</mo> <mo>-</mo> <mo>-</mo> <mrow> <mo>(</mo> <mn>8</mn> <mo>)</mo> </mrow> </mrow>

<mrow> <msub> <mover> <mi>f</mi> <mo>&amp;CenterDot;</mo> </mover> <mrow> <mi>d</mi> <mn>1</mn> </mrow> </msub> <mo>=</mo> <msub> <mi>D&amp;sigma;</mi> <mi>e</mi> </msub> <mo>|</mo> <msubsup> <mover> <mi>&amp;epsiv;</mi> <mo>&amp;CenterDot;</mo> </mover> <mi>e</mi> <mi>p</mi> </msubsup> <mo>|</mo> <mo>/</mo> <msup> <mrow> <mo>(</mo> <mn>1</mn> <mo>-</mo> <msub> <mi>f</mi> <mrow> <mi>d</mi> <mn>1</mn> </mrow> </msub> <mo>)</mo> </mrow> <msub> <mi>&amp;gamma;</mi> <mn>2</mn> </msub> </msup> <mo>-</mo> <mo>-</mo> <mo>-</mo> <mrow> <mo>(</mo> <mn>9</mn> <mo>)</mo> </mrow> </mrow>

<mrow> <msub> <mi>&amp;sigma;</mi> <mrow> <mi>i</mi> <mi>j</mi> </mrow> </msub> <mo>=</mo> <msub> <mi>D</mi> <mrow> <mi>i</mi> <mi>j</mi> <mi>k</mi> <mi>l</mi> </mrow> </msub> <mrow> <mo>(</mo> <mn>1</mn> <mo>-</mo> <msub> <mi>f</mi> <mrow> <mi>d</mi> <mn>1</mn> </mrow> </msub> <mo>)</mo> </mrow> <mrow> <mo>(</mo> <msubsup> <mi>&amp;epsiv;</mi> <mrow> <mi>k</mi> <mi>l</mi> </mrow> <mi>T</mi> </msubsup> <mo>-</mo> <msubsup> <mi>&amp;epsiv;</mi> <mrow> <mi>k</mi> <mi>l</mi> </mrow> <mi>P</mi> </msubsup> <mo>)</mo> </mrow> <mo>-</mo> <mo>-</mo> <mo>-</mo> <mrow> <mo>(</mo> <mn>10</mn> <mo>)</mo> </mrow> </mrow>

<mrow> <msub> <mi>D</mi> <mrow> <mi>i</mi> <mi>j</mi> <mi>k</mi> <mi>l</mi> </mrow> </msub> <mo>=</mo> <mfrac> <mi>E</mi> <mrow> <mn>2</mn> <mrow> <mo>(</mo> <mn>1</mn> <mo>+</mo> <mi>v</mi> <mo>)</mo> </mrow> </mrow> </mfrac> <mrow> <mo>(</mo> <msub> <mi>&amp;delta;</mi> <mrow> <mi>i</mi> <mi>l</mi> </mrow> </msub> <msub> <mi>&amp;delta;</mi> <mrow> <mi>j</mi> <mi>k</mi> </mrow> </msub> <mo>+</mo> <msub> <mi>&amp;delta;</mi> <mrow> <mi>i</mi> <mi>k</mi> </mrow> </msub> <msub> <mi>&amp;delta;</mi> <mrow> <mi>j</mi> <mi>l</mi> </mrow> </msub> <mo>)</mo> </mrow> <mo>+</mo> <mfrac> <mrow> <mi>E</mi> <mi>v</mi> </mrow> <mrow> <mo>(</mo> <mn>1</mn> <mo>+</mo> <mi>v</mi> <mo>)</mo> <mo>(</mo> <mn>1</mn> <mo>-</mo> <mn>2</mn> <mi>v</mi> <mo>)</mo> </mrow> </mfrac> <msub> <mi>&amp;delta;</mi> <mrow> <mi>i</mi> <mi>j</mi> </mrow> </msub> <msub> <mi>&amp;delta;</mi> <mrow> <mi>k</mi> <mi>l</mi> </mrow> </msub> <mo>-</mo> <mo>-</mo> <mo>-</mo> <mrow> <mo>(</mo> <mn>11</mn> <mo>)</mo> </mrow> </mrow>

In formula：Equivalent plastic strain rate when being shaping；σ_eEquivalent stress when being shaping；When H is shaping as caused by dislocation Strain hardening；Shape damage variable f_d1, excursion is 0~1, f_d1Represent that material does not damage during shaping when=0, f_d1=1 When represent shaping when material it is entirely ineffective；Plastic strain rate component during to shape；S_ijDeviatoric stress component during to shape；ρ_iFor the dislocation density under material original state, ρ_mThe accessible maximum dislocation of material is close during to shape Degree, and ρ_i≤ρ≤ρ_m, i.e.,σ_ijStress tensor component when being shaping；Overall strain component of tensor when being shaping；Plastic strain component of tensor when being shaping；D_ijklIt is quadravalence Stiffness Tensor component；E is Young's modulus；υ is Poisson's ratio；δ_ij For the Kronecker factor, subscript i, j, k, l excursion are 1~3, repeat subscript and follow Einstein's summation convention；

Parameter z, K, n₁, B, C, D, E be with the relevant material parameter of temperature, be defined as follows：

Z=z₀exp(Q_k/RT) (12)

K=K₀exp(Q_K/RT) (13)

n₁=n₁₀exp(Q_n/RT) (14)

B=B₀exp(Q_B/RT) (15)

C=C₀exp(-Q_C/RT) (16)

D=D₀exp(Q_D/RT) (17)

E=E₀exp(Q_E/RT) (18)

In formula：R is universal gas constant；T is temperature；Q is activation energy；

(2) material parameter in constitutive equation is determined：

First, the object function of Solve problems is established, then object function application Evolutionary Programming Algorithm is optimized, it is final true Determine the material parameter in constitutive equation, here, it is thus necessary to determine that a total of 20 of material parameter, be followed successively by：A、n₂、γ₁、γ₂、 z₀、n₀、K₀、n₁₀、B₀、C₀、D₀、E₀、Q_k、Q_K、Q_n、Q_B、Q_C、Q_D、Q_E、R；

Object function is established according to the distance between matched curve and test data：

<mrow> <mi>f</mi> <mrow> <mo>(</mo> <mi>x</mi> <mo>)</mo> </mrow> <mo>=</mo> <mfrac> <mn>1</mn> <mi>n</mi> </mfrac> <munderover> <mo>&amp;Sigma;</mo> <mrow> <mi>i</mi> <mo>=</mo> <mn>1</mn> </mrow> <mi>n</mi> </munderover> <msub> <mi>w</mi> <mi>i</mi> </msub> <msubsup> <mi>r</mi> <mi>i</mi> <mn>2</mn> </msubsup> <mo>=</mo> <mfrac> <mn>1</mn> <mi>n</mi> </mfrac> <munderover> <mo>&amp;Sigma;</mo> <mrow> <mi>i</mi> <mo>=</mo> <mn>1</mn> </mrow> <mi>n</mi> </munderover> <msub> <mi>w</mi> <mi>i</mi> </msub> <mrow> <mo>(</mo> <msup> <mi>&amp;Delta;&amp;sigma;</mi> <mn>2</mn> </msup> <mo>+</mo> <msup> <mi>&amp;Delta;&amp;epsiv;</mi> <mn>2</mn> </msup> <mo>)</mo> </mrow> <mo>=</mo> <mfrac> <mn>1</mn> <mi>n</mi> </mfrac> <munderover> <mo>&amp;Sigma;</mo> <mrow> <mi>i</mi> <mo>=</mo> <mn>1</mn> </mrow> <mi>n</mi> </munderover> <msub> <mi>w</mi> <mi>i</mi> </msub> <mrow> <mo>(</mo> <msup> <mrow> <mo>(</mo> <mrow> <msubsup> <mi>&amp;sigma;</mi> <mi>i</mi> <mi>c</mi> </msubsup> <mo>-</mo> <msubsup> <mi>&amp;sigma;</mi> <mi>i</mi> <mi>e</mi> </msubsup> </mrow> <mo>)</mo> </mrow> <mn>2</mn> </msup> <mo>+</mo> <msup> <mrow> <mo>(</mo> <mrow> <msubsup> <mi>&amp;epsiv;</mi> <mi>i</mi> <mi>c</mi> </msubsup> <mo>-</mo> <msubsup> <mi>&amp;epsiv;</mi> <mi>i</mi> <mi>e</mi> </msubsup> </mrow> <mo>)</mo> </mrow> <mn>2</mn> </msup> <mo>)</mo> </mrow> <mo>-</mo> <mo>-</mo> <mo>-</mo> <mrow> <mo>(</mo> <mn>19</mn> <mo>)</mo> </mrow> </mrow>

In formula：F (x) is to form vector x=(A, n on 20 unknown material parameters₂,...,Q_E, R) real-valued function；N is The total capacity of test data；w_iFor the weighted value of the i-th data point；The corresponding stress of respectively i-th of test data and Strain value；Respectively with the stress and strain value in the corresponding matched curve of i-th of test dataIt is restrained for matched curve is made to strain section to test data, it willF (x) is added in obtain It arrives：

<mrow> <mi>f</mi> <mrow> <mo>(</mo> <mi>x</mi> <mo>)</mo> </mrow> <mo>=</mo> <mfrac> <mn>1</mn> <mi>n</mi> </mfrac> <munderover> <mo>&amp;Sigma;</mo> <mrow> <mi>i</mi> <mo>=</mo> <mn>1</mn> </mrow> <mi>n</mi> </munderover> <msub> <mi>w</mi> <mi>i</mi> </msub> <mrow> <mo>(</mo> <msup> <mrow> <mo>(</mo> <mrow> <msubsup> <mi>&amp;sigma;</mi> <mi>i</mi> <mi>c</mi> </msubsup> <mo>-</mo> <msubsup> <mi>&amp;sigma;</mi> <mi>i</mi> <mi>e</mi> </msubsup> </mrow> <mo>)</mo> </mrow> <mn>2</mn> </msup> <mo>+</mo> <msup> <mrow> <mo>(</mo> <mrow> <msubsup> <mi>&amp;epsiv;</mi> <mi>i</mi> <mi>c</mi> </msubsup> <mo>-</mo> <msubsup> <mi>&amp;epsiv;</mi> <mi>i</mi> <mi>e</mi> </msubsup> </mrow> <mo>)</mo> </mrow> <mn>2</mn> </msup> <mo>)</mo> </mrow> <mo>+</mo> <mi>W</mi> <msup> <mrow> <mo>(</mo> <msubsup> <mi>&amp;epsiv;</mi> <mi>n</mi> <mi>c</mi> </msubsup> <mo>-</mo> <msubsup> <mi>&amp;epsiv;</mi> <mi>n</mi> <mi>e</mi> </msubsup> <mo>)</mo> </mrow> <mn>2</mn> </msup> <mo>-</mo> <mo>-</mo> <mo>-</mo> <mrow> <mo>(</mo> <mn>20</mn> <mo>)</mo> </mrow> </mrow>

In formula：W is weight coefficient；

To reduce the difficulty of definite weighted value in actual use and overcoming the problems, such as that ess-strain unit is inconsistent, finally build Vertical object function is as follows：

<mrow> <mi>f</mi> <mrow> <mo>(</mo> <mi>x</mi> <mo>)</mo> </mrow> <mo>=</mo> <mfrac> <mn>1</mn> <mi>n</mi> </mfrac> <munderover> <mo>&amp;Sigma;</mo> <mrow> <mi>i</mi> <mo>=</mo> <mn>1</mn> </mrow> <mi>n</mi> </munderover> <mrow> <mo>(</mo> <mi>w</mi> <msub> <mn>1</mn> <mi>i</mi> </msub> <msup> <mrow> <mo>(</mo> <mrow> <mi>ln</mi> <mrow> <mo>(</mo> <mfrac> <mrow> <msubsup> <mi>&amp;sigma;</mi> <mi>i</mi> <mi>c</mi> </msubsup> <mrow> <mo>(</mo> <msubsup> <mi>&amp;epsiv;</mi> <mi>i</mi> <mi>e</mi> </msubsup> <msubsup> <mi>&amp;epsiv;</mi> <mi>n</mi> <mi>c</mi> </msubsup> <mo>/</mo> <msubsup> <mi>&amp;epsiv;</mi> <mi>n</mi> <mi>e</mi> </msubsup> <mo>)</mo> </mrow> </mrow> <msubsup> <mi>&amp;sigma;</mi> <mi>i</mi> <mi>e</mi> </msubsup> </mfrac> <mo>)</mo> </mrow> </mrow> <mo>)</mo> </mrow> <mn>2</mn> </msup> <mo>+</mo> <mi>w</mi> <msub> <mn>2</mn> <mi>i</mi> </msub> <msup> <mrow> <mo>(</mo> <mrow> <mi>ln</mi> <mrow> <mo>(</mo> <mfrac> <mrow> <msubsup> <mi>&amp;epsiv;</mi> <mi>i</mi> <mi>c</mi> </msubsup> <mrow> <mo>(</mo> <msubsup> <mi>&amp;epsiv;</mi> <mi>i</mi> <mi>e</mi> </msubsup> <msubsup> <mi>&amp;epsiv;</mi> <mi>n</mi> <mi>c</mi> </msubsup> <mo>/</mo> <msubsup> <mi>&amp;epsiv;</mi> <mi>n</mi> <mi>e</mi> </msubsup> <mo>)</mo> </mrow> </mrow> <msubsup> <mi>&amp;epsiv;</mi> <mi>i</mi> <mi>e</mi> </msubsup> </mfrac> <mo>)</mo> </mrow> </mrow> <mo>)</mo> </mrow> <mn>2</mn> </msup> <mo>)</mo> </mrow> <mo>+</mo> <msup> <mrow> <mo>(</mo> <msubsup> <mi>&amp;epsiv;</mi> <mi>n</mi> <mi>c</mi> </msubsup> <mo>-</mo> <msubsup> <mi>&amp;epsiv;</mi> <mi>n</mi> <mi>e</mi> </msubsup> <mo>)</mo> </mrow> <mn>2</mn> </msup> <mo>-</mo> <mo>-</mo> <mo>-</mo> <mrow> <mo>(</mo> <mn>21</mn> <mo>)</mo> </mrow> </mrow>

In formula：

<mrow> <mi>w</mi> <msub> <mn>1</mn> <mi>i</mi> </msub> <mo>=</mo> <msubsup> <mi>n&amp;epsiv;</mi> <mi>i</mi> <mi>e</mi> </msubsup> <mo>/</mo> <munderover> <mo>&amp;Sigma;</mo> <mrow> <mi>i</mi> <mo>=</mo> <mn>1</mn> </mrow> <mi>n</mi> </munderover> <msubsup> <mi>&amp;epsiv;</mi> <mi>i</mi> <mi>e</mi> </msubsup> <mo>,</mo> <mrow> <mo>(</mo> <mi>w</mi> <msub> <mn>1</mn> <mn>1</mn> </msub> <mo>+</mo> <mi>w</mi> <msub> <mn>1</mn> <mn>2</mn> </msub> <mo>+</mo> <mn>...</mn> <mo>+</mo> <mi>w</mi> <msub> <mn>1</mn> <mi>n</mi> </msub> <mo>=</mo> <mi>n</mi> <mo>)</mo> </mrow> <mo>-</mo> <mo>-</mo> <mo>-</mo> <mrow> <mo>(</mo> <mn>22</mn> <mo>)</mo> </mrow> </mrow>

<mrow> <mi>w</mi> <msub> <mn>2</mn> <mi>i</mi> </msub> <mo>=</mo> <msubsup> <mi>n&amp;epsiv;</mi> <mi>i</mi> <mi>e</mi> </msubsup> <mo>/</mo> <munderover> <mo>&amp;Sigma;</mo> <mrow> <mi>i</mi> <mo>=</mo> <mn>1</mn> </mrow> <mi>n</mi> </munderover> <msubsup> <mi>&amp;epsiv;</mi> <mi>i</mi> <mi>e</mi> </msubsup> <mo>,</mo> <mrow> <mo>(</mo> <mi>w</mi> <msub> <mn>2</mn> <mn>1</mn> </msub> <mo>+</mo> <mi>w</mi> <msub> <mn>2</mn> <mn>2</mn> </msub> <mo>+</mo> <mn>...</mn> <mo>+</mo> <mi>w</mi> <msub> <mn>2</mn> <mi>n</mi> </msub> <mo>=</mo> <mi>n</mi> <mo>)</mo> </mrow> <mo>-</mo> <mo>-</mo> <mo>-</mo> <mrow> <mo>(</mo> <mn>23</mn> <mo>)</mo> </mrow> </mrow>

The object function of foundation is optimized using improved tachytelic evolution planning algorithm, determines all material parameter, is evolved Planning algorithm is using object function as biotic population, and by mutation, selection generates population of new generation；This process is repeated, until It is the process of an iteration to obtain the population to meet the requirements or defined evolution time limit, detailed evolutional programming：

[1] iteration count k=1 is taken, generates μ population at random, i.e. stochastic inputs μ groups vector is to (x_i,η_i), whereinη_iFor evolutional programming adaptive strategy parameter, i=1,2,3 ..., μ；

[2] for each individual vector to (x_i,η_i), calculate f (x_i)；

[3] for each parent vector to (x_i,η_i), generate two filial generation vectors pairWithWherein：

<mrow> <mfenced open = "{" close = ""> <mtable> <mtr> <mtd> <mrow> <msubsup> <mi>x</mi> <mi>i</mi> <mn>1</mn> </msubsup> <mrow> <mo>(</mo> <mi>j</mi> <mo>)</mo> </mrow> <mo>=</mo> <msub> <mi>x</mi> <mi>i</mi> </msub> <mrow> <mo>(</mo> <mi>j</mi> <mo>)</mo> </mrow> <mo>+</mo> <msub> <mi>&amp;eta;</mi> <mi>i</mi> </msub> <mrow> <mo>(</mo> <mi>j</mi> <mo>)</mo> </mrow> <msub> <mi>N</mi> <mi>j</mi> </msub> <mrow> <mo>(</mo> <mn>0</mn> <mo>,</mo> <mn>1</mn> <mo>)</mo> </mrow> </mrow> </mtd> </mtr> <mtr> <mtd> <mrow> <msubsup> <mi>x</mi> <mi>i</mi> <mn>2</mn> </msubsup> <mrow> <mo>(</mo> <mi>j</mi> <mo>)</mo> </mrow> <mo>=</mo> <msub> <mi>x</mi> <mi>i</mi> </msub> <mrow> <mo>(</mo> <mi>j</mi> <mo>)</mo> </mrow> <mo>+</mo> <msub> <mi>&amp;eta;</mi> <mi>i</mi> </msub> <mrow> <mo>(</mo> <mi>j</mi> <mo>)</mo> </mrow> <msub> <mi>&amp;delta;</mi> <mi>j</mi> </msub> </mrow> </mtd> </mtr> <mtr> <mtd> <mrow> <msubsup> <mi>&amp;eta;</mi> <mi>i</mi> <mn>1</mn> </msubsup> <mrow> <mo>(</mo> <mi>j</mi> <mo>)</mo> </mrow> <mo>=</mo> <msub> <mi>&amp;eta;</mi> <mi>i</mi> </msub> <mrow> <mo>(</mo> <mi>j</mi> <mo>)</mo> </mrow> <mi>exp</mi> <mrow> <mo>(</mo> <msup> <mi>&amp;tau;</mi> <mn>1</mn> </msup> <mi>N</mi> <mo>(</mo> <mrow> <mn>0</mn> <mo>,</mo> <mn>1</mn> </mrow> <mo>)</mo> <mo>+</mo> <msub> <mi>&amp;tau;N</mi> <mi>j</mi> </msub> <mo>(</mo> <mrow> <mn>0</mn> <mo>,</mo> <mn>1</mn> </mrow> <mo>)</mo> <mo>)</mo> </mrow> </mrow> </mtd> </mtr> </mtable> </mfenced> <mo>-</mo> <mo>-</mo> <mo>-</mo> <mrow> <mo>(</mo> <mn>24</mn> <mo>)</mo> </mrow> </mrow>

It calculates and comparesWithSize, both take the vector pair corresponding to smaller, be denoted as (x_i',η_i'), Wherein x_i(j), x_i' (j), η_i(j), η_i' (j) be respectively vector x_i, x_i', η_i, η_i' j-th of component, j=1,2 ..., P, P be The number of material parameter to be optimized；N (0,1) is the random number for obeying one-dimensional standardized normal distribution；N_j(0,1) it is the one-dimensional mark of obedience Quasi normal distribution corresponds to the random number of j-th of component；δ_jTo obey the random number that Cauchy's distribution corresponds to j-th of component；Ginseng Number τ¹It is taken respectively with τWithStandardized normal distribution and the density function of Cauchy's distribution are respectively：

<mrow> <msub> <mi>f</mi> <mi>N</mi> </msub> <mrow> <mo>(</mo> <mi>x</mi> <mo>)</mo> </mrow> <mo>=</mo> <mfrac> <mn>1</mn> <msqrt> <mrow> <mn>2</mn> <mi>P</mi> </mrow> </msqrt> </mfrac> <msup> <mi>e</mi> <mrow> <mo>-</mo> <msup> <mi>x</mi> <mn>2</mn> </msup> <mo>/</mo> <mn>2</mn> </mrow> </msup> <mo>,</mo> <mo>-</mo> <mi>&amp;infin;</mi> <mo>&lt;</mo> <mi>x</mi> <mo>&lt;</mo> <mo>+</mo> <mi>&amp;infin;</mi> <mo>-</mo> <mo>-</mo> <mo>-</mo> <mrow> <mo>(</mo> <mn>25</mn> <mo>)</mo> </mrow> </mrow>

<mrow> <msub> <mi>f</mi> <mi>&amp;delta;</mi> </msub> <mrow> <mo>(</mo> <mi>x</mi> <mo>)</mo> </mrow> <mo>=</mo> <mfrac> <mn>1</mn> <mi>&amp;pi;</mi> </mfrac> <mfrac> <mn>1</mn> <mrow> <mn>1</mn> <mo>+</mo> <msup> <mi>x</mi> <mn>2</mn> </msup> </mrow> </mfrac> <mo>,</mo> <mo>-</mo> <mi>&amp;infin;</mi> <mo>&lt;</mo> <mi>x</mi> <mo>&lt;</mo> <mo>+</mo> <mi>&amp;infin;</mi> <mo>-</mo> <mo>-</mo> <mo>-</mo> <mrow> <mo>(</mo> <mn>26</mn> <mo>)</mo> </mrow> </mrow>

[4] for all i=1,2,3 ..., μ, by all parent vectors to (x_i,η_i) and filial generation vector to (x_i',η_i') As an entirety, q vector pair is taken out, then, by all parents and any one vector pair of filial generation vector centering with taking The q vector gone out compares vector to corresponding target function value, if the vector is to being less than q vector centering to making comparisons Some, then the vector adds score 1, and the top score of all vectors pair is q, minimum to be scored at 0；

[5] μ vector pair of highest scoring, the parent vector pair as next iteration are selected from 2 μ vectors pair；

[6] judge whether iteration termination condition meets；It is such as unsatisfactory for, then k=k+1, and repeats the above process；

(3) software of damage Constitutive Equation is realized

The shaping damage Constitutive Equation for having determined that material parameter is written as Ls-dyna User Defineds using Fortran language Material subprogram is embedded by User Defined material subprogram interface in finite element software Ls-dyna；

Step 2: the hot forming of vehicle body high intensity crashworthiness part is simulated, detailed process is：

1) vehicle body high intensity crashworthiness part hot forming simulation model is established using Hypermesh finite element softwares, pair in model As including plate (6), punch-pin (4), cavity plate (7) and blank holder (5)；

2) be respectively in model each object assign section attribute and material property, all objects using shell unit section attribute, And the thickness th of each object is defined wherein, and punch-pin (4), cavity plate (7) and blank holder (5) be using rigid body physical material, and The density p of each object, elastic modulus E and Poisson's ratio υ defined in it, and plate (6) is then using the above-mentioned use based on shaping damage The self-defined physical material in family, and all objects are using isotropism hot material, and define the specific heat capacity HC of each object wherein And coefficient of heat conduction TC；

3) contact relation in model between each object is set, define temperature field, kinetic characteristic, constraints that each object has and Model calculates required control card；

4) vehicle body high intensity crashworthiness part hot forming simulation model, the part mould after being shaped are solved using Ls-dyna softwares Type and its shaping damage cloud atlas and thickness distribution cloud atlas；

Step 3：Vehicle body high intensity crashworthiness part crashworthiness Simulation Evaluation：

1) mechanics uses property database

(1) material at high temperature damage test

Virtual test is carried out to test specimen (2) using Ls-dyna softwares, entire test specimen (2) uses shell unit section attribute, and at it Defined in test specimen (2) thickness TH, using consider shaping damage User Defined physical material and isotropism hot material, and Its specific heat capacity HC and coefficient of heat conduction TC defined in it, meanwhile, define l in test specimen (2) intermediate region₀The samming of=25mm long Section, applies steady temperature field in the section, and at left and right sides of this section region then according to actual tests in test specimen (2) Temperature Distribution Apply corresponding temperature field, during virtual test, all 6 degree of freedom of constraint test specimen (2) left end node apply in right end along axis To the forced displacement changed over time, it is ensured that equal temperature section is deformed with constant strain rate, and equal temperature section is made to take typical case in experiment Experimental condition：750 DEG C of forming temperature, deformation strain rate 0.1s^-1；Under this condition, a series of virtual tests are carried out, make samming The shaping impairment value of unit respectively reaches target shaping impairment value 0, α in section₁,α₂,......,α_MTo get to a series of equal temperature sections Test specimen (8) after stretching with differing formed impairment value, and the changing value of each test specimen (2) samming segment length is measured respectivelyM represents the number for the non-zero target shaping impairment value that serial virtual test is reached；

Actual tests are carried out to test specimen (2) using testing machine, actual test conditions are identical with virtual test, and CCD is utilized in experiment Video camera (3) is shot, and passes through the deflection of ARAMIS optical skew system Real-time Feedback test specimens (2) temperature section, when each The variation of test specimen (2) samming segment length respectively reachesWhen, stop stretching, at this point, samming in actual tests Material reaches with equal degree of injury in virtual test at section, same samming segment length changing value Repeated m time experiment in experiment；With Afterwards, each test specimen (2) temperature section rapid quenching is cooled to room temperature has differing formed impairment value to get to a series of equal temperature sections Test specimen (8) after the stretching of martensitic phase after quenching；

(2) test specimen is processed

Linear cutter is carried out to test specimen (8) after a series of quenched stretchings for being obtained in material at high temperature damage test, is obtained For sub- test specimen (9) used in material room temperature one directional tensile test, then, each surface of all sub- test specimens (9) is carried out with fine sandpaper Slight polishing, removes oxide skin above, and records the minimum sectional area of each sub- test specimen (9) gauge length section after polishing, as following The original cross-sectional area A of material room temperature one directional tensile test neutron test specimen (9) gauge length section₀；

(3) material room temperature one directional tensile test

There is the sub- test specimen of different impairment values using electronic universal tester to the equal temperature section obtained in material at high temperature damage test (9) one directional tensile test of m kind difference military service strain rates is carried out, all sub- test specimens (9) are stretched at room temperature until fracture, whole The curve F (t) that chance record load changes over time is tested in a drawing process, and it is scaled sub- examination according to formula (1) The curve σ that the nominal stress of part (9) changes over time_nom(t), the gauge length segment length of sub- test specimen (9) is measured using stretching to extend The curve Δ L (t) changed over time is spent, and it is scaled the gauge length section apparent strain of sub- test specimen (9) at any time according to formula (2) Between the curve ε that changes_nom(t), the curve σ changed over time the nominal stress of sub- test specimen (9) according to formula (3)_nom(t) convert The curve σ changed over time for the true stress of sub- test specimen (9)_true(t), according to formula (4) by the gauge length section name of sub- test specimen (9) The curve ε that justice strain changes over time_nom(t) it is scaled the curve that the gauge length section logarithmic strain of sub- test specimen (9) changes over time ε_true(t), and the time variable t in two curves is eliminated, with logarithmic strain ε_trueFor independent variable, true stress σ_trueFor dependent variable, Obtain the true stress and strain curve σ of each test specimen (9)_true(ε_true)；Finally, obtain with differing formed impairment value, different clothes Use as a servant the true stress and strain curve σ of the test specimen (9) of strain rate_true(ε_true), for establishing following military services for considering shaping damage Constitutive equation；

2) the military service constitutive equation for considering shaping damage is established

The military service constitutive equation for considering shaping damage is established, expression is as follows：

<mrow> <msup> <mover> <mi>&amp;epsiv;</mi> <mo>&amp;CenterDot;</mo> </mover> <mi>p</mi> </msup> <mo>=</mo> <msup> <mrow> <mo>(</mo> <mfrac> <mrow> <mi>&amp;sigma;</mi> <mo>/</mo> <mrow> <mo>(</mo> <mn>1</mn> <mo>-</mo> <msub> <mi>f</mi> <mrow> <mi>d</mi> <mn>2</mn> </mrow> </msub> <mo>)</mo> </mrow> <mo>-</mo> <mi>F</mi> <msup> <msub> <mover> <mi>&amp;rho;</mi> <mo>&amp;OverBar;</mo> </mover> <mi>s</mi> </msub> <msub> <mi>n</mi> <mi>a</mi> </msub> </msup> <mo>-</mo> <mi>y</mi> </mrow> <mi>Y</mi> </mfrac> <mo>)</mo> </mrow> <msub> <mi>n</mi> <mi>c</mi> </msub> </msup> <msup> <mrow> <mo>(</mo> <mfrac> <mn>1</mn> <mrow> <mn>1</mn> <mo>-</mo> <msub> <mi>f</mi> <mrow> <mi>d</mi> <mn>2</mn> </mrow> </msub> </mrow> </mfrac> <mo>)</mo> </mrow> <msub> <mi>&amp;gamma;</mi> <mn>3</mn> </msub> </msup> <mo>-</mo> <mo>-</mo> <mo>-</mo> <mrow> <mo>(</mo> <mn>27</mn> <mo>)</mo> </mrow> </mrow>

<mrow> <msubsup> <mover> <mi>&amp;epsiv;</mi> <mo>&amp;CenterDot;</mo> </mover> <mrow> <mi>i</mi> <mi>j</mi> </mrow> <mi>p</mi> </msubsup> <mo>=</mo> <mfrac> <mrow> <mn>3</mn> <msub> <mi>S</mi> <mrow> <mi>s</mi> <mo>-</mo> <mi>i</mi> <mi>j</mi> </mrow> </msub> </mrow> <mrow> <mn>2</mn> <mi>&amp;sigma;</mi> </mrow> </mfrac> <msup> <mover> <mi>&amp;epsiv;</mi> <mo>&amp;CenterDot;</mo> </mover> <mi>p</mi> </msup> <mo>-</mo> <mo>-</mo> <mo>-</mo> <mrow> <mo>(</mo> <mn>28</mn> <mo>)</mo> </mrow> </mrow>

<mrow> <msub> <mover> <mover> <mi>&amp;rho;</mi> <mo>&amp;OverBar;</mo> </mover> <mo>&amp;CenterDot;</mo> </mover> <mi>s</mi> </msub> <mo>=</mo> <mi>Z</mi> <mrow> <mo>(</mo> <mn>1</mn> <mo>-</mo> <msub> <mover> <mi>&amp;rho;</mi> <mo>&amp;OverBar;</mo> </mover> <mi>s</mi> </msub> <mo>)</mo> </mrow> <mo>|</mo> <msup> <mover> <mi>&amp;epsiv;</mi> <mo>&amp;CenterDot;</mo> </mover> <mi>p</mi> </msup> <mo>|</mo> <mo>-</mo> <mi>G</mi> <msup> <msub> <mover> <mi>&amp;rho;</mi> <mo>&amp;OverBar;</mo> </mover> <mi>s</mi> </msub> <msub> <mi>&amp;gamma;</mi> <mn>4</mn> </msub> </msup> <mo>-</mo> <mo>-</mo> <mo>-</mo> <mrow> <mo>(</mo> <mn>29</mn> <mo>)</mo> </mrow> </mrow>

<mrow> <msub> <mover> <mi>f</mi> <mo>&amp;CenterDot;</mo> </mover> <mrow> <mi>d</mi> <mn>2</mn> </mrow> </msub> <mo>=</mo> <msub> <mi>&amp;beta;</mi> <mn>1</mn> </msub> <mrow> <mo>(</mo> <mi>&amp;sigma;</mi> <msup> <mover> <mi>&amp;epsiv;</mi> <mo>&amp;CenterDot;</mo> </mover> <mi>p</mi> </msup> <mo>)</mo> </mrow> <msup> <msub> <mi>f</mi> <mrow> <mi>d</mi> <mn>2</mn> </mrow> </msub> <msub> <mi>&amp;gamma;</mi> <mn>5</mn> </msub> </msup> <mo>+</mo> <mfrac> <mrow> <msub> <mi>&amp;beta;</mi> <mn>2</mn> </msub> <msup> <mrow> <mo>(</mo> <msup> <mover> <mi>&amp;epsiv;</mi> <mo>&amp;CenterDot;</mo> </mover> <mi>p</mi> </msup> <mo>)</mo> </mrow> <msub> <mi>&amp;gamma;</mi> <mn>6</mn> </msub> </msup> <mi>cosh</mi> <mrow> <mo>(</mo> <msub> <mi>&amp;beta;</mi> <mn>3</mn> </msub> <msup> <mover> <mi>&amp;epsiv;</mi> <mo>&amp;CenterDot;</mo> </mover> <mi>p</mi> </msup> <mo>)</mo> </mrow> </mrow> <msup> <mrow> <mo>(</mo> <mn>1</mn> <mo>-</mo> <msub> <mi>f</mi> <mrow> <mi>d</mi> <mn>2</mn> </mrow> </msub> <mo>)</mo> </mrow> <msub> <mi>&amp;gamma;</mi> <mn>7</mn> </msub> </msup> </mfrac> <mo>-</mo> <mo>-</mo> <mo>-</mo> <mrow> <mo>(</mo> <mn>30</mn> <mo>)</mo> </mrow> </mrow>

<mrow> <msub> <mi>&amp;sigma;</mi> <mrow> <mi>s</mi> <mo>-</mo> <mi>i</mi> <mi>j</mi> </mrow> </msub> <mo>=</mo> <msub> <mi>D</mi> <mrow> <mi>s</mi> <mo>-</mo> <mi>i</mi> <mi>j</mi> <mi>k</mi> <mi>l</mi> </mrow> </msub> <mrow> <mo>(</mo> <mn>1</mn> <mo>-</mo> <msub> <mi>f</mi> <mrow> <mi>d</mi> <mn>2</mn> </mrow> </msub> <mo>)</mo> </mrow> <mrow> <mo>(</mo> <msubsup> <mi>&amp;epsiv;</mi> <mrow> <mi>k</mi> <mi>l</mi> </mrow> <mi>t</mi> </msubsup> <mo>-</mo> <msubsup> <mi>&amp;epsiv;</mi> <mrow> <mi>k</mi> <mi>l</mi> </mrow> <mi>p</mi> </msubsup> <mo>)</mo> </mrow> <mo>-</mo> <mo>-</mo> <mo>-</mo> <mrow> <mo>(</mo> <mn>31</mn> <mo>)</mo> </mrow> </mrow>

<mrow> <msub> <mi>D</mi> <mrow> <mi>s</mi> <mo>-</mo> <mi>i</mi> <mi>j</mi> <mi>k</mi> <mi>l</mi> </mrow> </msub> <mo>=</mo> <mfrac> <mi>L</mi> <mrow> <mn>2</mn> <mrow> <mo>(</mo> <mn>1</mn> <mo>+</mo> <mi>v</mi> <mo>)</mo> </mrow> </mrow> </mfrac> <mrow> <mo>(</mo> <msub> <mi>&amp;delta;</mi> <mrow> <mi>i</mi> <mi>l</mi> </mrow> </msub> <msub> <mi>&amp;delta;</mi> <mrow> <mi>j</mi> <mi>k</mi> </mrow> </msub> <mo>+</mo> <msub> <mi>&amp;delta;</mi> <mrow> <mi>i</mi> <mi>k</mi> </mrow> </msub> <msub> <mi>&amp;delta;</mi> <mrow> <mi>j</mi> <mi>l</mi> </mrow> </msub> <mo>)</mo> </mrow> <mo>+</mo> <mfrac> <mrow> <mi>L</mi> <mi>v</mi> </mrow> <mrow> <mo>(</mo> <mn>1</mn> <mo>+</mo> <mi>v</mi> <mo>)</mo> <mo>(</mo> <mn>1</mn> <mo>-</mo> <mn>2</mn> <mi>v</mi> <mo>)</mo> </mrow> </mfrac> <msub> <mi>&amp;delta;</mi> <mrow> <mi>i</mi> <mi>j</mi> </mrow> </msub> <msub> <mi>&amp;delta;</mi> <mrow> <mi>k</mi> <mi>l</mi> </mrow> </msub> <mo>-</mo> <mo>-</mo> <mo>-</mo> <mrow> <mo>(</mo> <mn>32</mn> <mo>)</mo> </mrow> </mrow>

In formula：It is equivalent plastic strain rate when being on active service；σ is equivalent stress when being on active service；Military service damage variable f_d2, variation Scope is 0~1, f_d2Material is not on active service damage when representing to be on active service when=0, f_d2Material is entirely ineffective when representing to be on active service when=1；Plastic strain rate component during to be on active service；S_s-ijDeviatoric stress component during to be on active service；ρ_siTo be on active service The dislocation density of preceding material, ρ_smMaterial accessible maximum dislocation density during to be on active service, and ρ_si≤ρ_s≤ρ_sm, i.e., σ_s-ijIt is stress tensor component when being on active service；It is overall strain component of tensor when being on active service；It is the plastic strain when being on active service Measure component；D_s-ijklIt is quadravalence Stiffness Tensor component；L is Young's modulus；υ is Poisson's ratio；δ_ijFor the Kronecker factor, subscript i, J, k, l excursion are 1~3, repeat subscript and follow Einstein's summation convention；

Parameter y, Y, F, G, L, β₁、β₂、β₃、γ₅、γ₆It is to damage relevant material parameter with shaping, is defined as follows：

Y=y₀exp(W_y/f_d1) (33)

Y=Y₀exp(W_Y/f_d1) (34)

F=F₀exp(W_F/f_d1) (35)

G=G₀exp(-W_G/f_d1) (36)

L=L₀exp(W_L/f_d1) (37)

<mrow> <msub> <mi>&amp;beta;</mi> <mn>1</mn> </msub> <mo>=</mo> <msub> <mi>&amp;beta;</mi> <mn>10</mn> </msub> <mi>exp</mi> <mrow> <mo>(</mo> <msub> <mi>W</mi> <msub> <mi>&amp;beta;</mi> <mn>1</mn> </msub> </msub> <mo>/</mo> <msub> <mi>f</mi> <mrow> <mi>d</mi> <mn>1</mn> </mrow> </msub> <mo>)</mo> </mrow> <mo>-</mo> <mo>-</mo> <mo>-</mo> <mrow> <mo>(</mo> <mn>38</mn> <mo>)</mo> </mrow> </mrow>

<mrow> <msub> <mi>&amp;beta;</mi> <mn>2</mn> </msub> <mo>=</mo> <msub> <mi>&amp;beta;</mi> <mn>20</mn> </msub> <mi>exp</mi> <mrow> <mo>(</mo> <msub> <mi>W</mi> <msub> <mi>&amp;beta;</mi> <mn>2</mn> </msub> </msub> <mo>/</mo> <msub> <mi>f</mi> <mrow> <mi>d</mi> <mn>1</mn> </mrow> </msub> <mo>)</mo> </mrow> <mo>-</mo> <mo>-</mo> <mo>-</mo> <mrow> <mo>(</mo> <mn>39</mn> <mo>)</mo> </mrow> </mrow>

<mrow> <msub> <mi>&amp;beta;</mi> <mn>3</mn> </msub> <mo>=</mo> <msub> <mi>&amp;beta;</mi> <mn>30</mn> </msub> <mi>exp</mi> <mrow> <mo>(</mo> <msub> <mi>W</mi> <msub> <mi>&amp;beta;</mi> <mn>3</mn> </msub> </msub> <mo>/</mo> <msub> <mi>f</mi> <mrow> <mi>d</mi> <mn>1</mn> </mrow> </msub> <mo>)</mo> </mrow> <mo>-</mo> <mo>-</mo> <mo>-</mo> <mrow> <mo>(</mo> <mn>40</mn> <mo>)</mo> </mrow> </mrow>

<mrow> <msub> <mi>&amp;gamma;</mi> <mn>5</mn> </msub> <mo>=</mo> <msub> <mi>&amp;gamma;</mi> <mn>50</mn> </msub> <mi>exp</mi> <mrow> <mo>(</mo> <msub> <mi>W</mi> <msub> <mi>&amp;gamma;</mi> <mn>5</mn> </msub> </msub> <mo>/</mo> <msub> <mi>f</mi> <mrow> <mi>d</mi> <mn>1</mn> </mrow> </msub> <mo>)</mo> </mrow> <mo>-</mo> <mo>-</mo> <mo>-</mo> <mrow> <mo>(</mo> <mn>41</mn> <mo>)</mo> </mrow> </mrow>

<mrow> <msub> <mi>&amp;gamma;</mi> <mn>6</mn> </msub> <mo>=</mo> <msub> <mi>&amp;gamma;</mi> <mn>60</mn> </msub> <mi>exp</mi> <mrow> <mo>(</mo> <msub> <mi>W</mi> <msub> <mi>&amp;gamma;</mi> <mn>6</mn> </msub> </msub> <mo>/</mo> <msub> <mi>f</mi> <mrow> <mi>d</mi> <mn>1</mn> </mrow> </msub> <mo>)</mo> </mrow> <mo>-</mo> <mo>-</mo> <mo>-</mo> <mrow> <mo>(</mo> <mn>42</mn> <mo>)</mo> </mrow> </mrow>

It determines to consider that the military service Material Parameter in Constitutive Equation of shaping damage and military service constitutive equation software realize method used Method used is identical during with establishing based on shaping damage Constitutive Equation, and here, it is thus necessary to determine that material parameter in total There are 25, be followed successively by：Z、γ₃、γ₄、γ₇、n_c、y₀、Y₀、F₀、G₀、L₀、β₁₀、β₂₀、β₃₀、γ₅₀、γ₆₀、W_y、W_Y、W_F、W_G、W_L、

3) vehicle body high intensity crashworthiness part virtual test

(1) vehicle body high intensity crashworthiness part virtual test model is established using Hypermesh softwares, in virtual crushing test model Object include：Rigid obstacle (10), conquassation thin-walled crashworthiness part (11)；Object in virtual bend test model includes：No. 1 Rigidity circle rolling (12), bending thin-walled crashworthiness part (13), No. 2 rigidity circle rollings (14), No. 3 rigidity circle rollings (15)；

(2) be respectively in model each object assign section attribute and material property, all objects using shell unit section attribute, The thickness distribution of crashworthiness part inherits the thickness distribution of part after hot forming, and rigid obstacle (10) and all rigidity circle rollings use Rigid body physical material, and density p, elastic modulus E and the Poisson's ratio υ of each object are defined wherein, and it is crushed thin-walled crashworthiness part (13) then it is on active service this structure physical material using the User Defined for considering shaping damage with bending thin-walled crashworthiness part (13)；

(3) contact relation in model between each object is set, and the kinetic characteristic, constraints and model for defining each object calculate institute The control card needed；

(4) vehicle body high intensity crashworthiness part virtual test model is solved using Ls-dyna softwares, output crashworthiness part becomes at any time Deformation tendency cloud atlas, contact force curve and the energy absorption curve of change, and compared with design object value, to confirm the crashworthiness zero Whether part meets design requirement.