CN108920847A - Springback compensation method for creep age forming - Google Patents
Springback compensation method for creep age forming Download PDFInfo
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- CN108920847A CN108920847A CN201810739174.8A CN201810739174A CN108920847A CN 108920847 A CN108920847 A CN 108920847A CN 201810739174 A CN201810739174 A CN 201810739174A CN 108920847 A CN108920847 A CN 108920847A
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- G06F30/00—Computer-aided design [CAD]
- G06F30/20—Design optimisation, verification or simulation
- G06F30/23—Design optimisation, verification or simulation using finite element methods [FEM] or finite difference methods [FDM]
Abstract
The present invention provides a kind of springback compensation method for creep age forming, and this approach includes the following steps：Step S100：Component creep age forming finite element simulation based on MSC.MARC commercialization finite element software；Step S200：Die face weighting rebound iterative compensation process based on FEM Numerical Simulation；Step S300:Consider the Contrary compensation process of die material type face thermal expansion effects.Considering that component intensity itself compensates type face in this method compensation influences；Consider the influence that component specification structure compensates type face；Consider the Contrary compensation of the thermal expansion in die material type face.Using the component of the model forming, Engineering Error requirement is still able to satisfy after cooling is handled.
Description
Technical field
The present invention relates to creep ageing Accurate Shaping manufacturing technology fields, are specifically related to a kind of for creep age forming
Springback compensation method.
Background technique
Creep age forming technology is the creep properties using metal, will shape one kind of progress synchronous with aging strengthening model
Manufacturing process.Creep age forming is particularly suitable for the large-scale integrated member of forming aerospace, which is used for molding component
When, it can guarantee that the Accurate Shaping of component becomes second nature with high-performance and mutually cooperate with.Creep age forming technology has forming accuracy height, molding
The at low cost, advantages such as repetitive rate is high, residual stress is low.However component is after creep age forming, since elastic recovery is made
Presence, material are inevitably sprung back.
In order to eliminate influence of the elastic recovery effect to component, frequently with springback compensation, in order to realize that springback compensation needs standard
The really rebound degree of prediction component.Material creep timeliness constitutive model is the key that Accurate Prediction member springs back rate.Existing structure mould
The external variable of the macroscopic view such as time, temperature, stress is based primarily upon in type.Due to needing, and it is outer to need to handle a large amount of macroscopic views every time
In variable data, existing type face tooling compensation process calculates time-consuming serious.
Summary of the invention
The purpose of the present invention is to provide a kind of springback compensation method for creep age forming, which solves existing
There is the technical problem that springback compensation the number of iterations is more, calculating is time-consuming, compensation precision is low in technology；.
The present invention provides a kind of springback compensation methods for creep age forming, include the following steps：
Step S100：Die face is inputted in MSC.MARC software, establishes limit element artificial module, carries out component creep
After age forming, creep component is obtained；
Step S200：Component outer mold surface after enabling each iterative compensation spring back is Pi(i=0,1,2,3 ..., 0 indicates first
It is secondary to emulate obtained rebound type face), deletion currently emulates the die face M usedi(i=0,1,2,3 ..., 0 indicates to imitate for the first time
The die face inputted when true, i.e. the object type face of component), reading element geometry object type face Pgoal, calculate the creep structure
Rebound outer mold surface P after part reboundiEach node is gone up to object type face PgoalThe vertical range Δ Z of upper each nodeij, Δ ZijIndicate the
Node j to object type face P on i iteration rear part rebound type facegoalVertical range, take vertical range Δ described in each node
ZijVertical range maximum value max (△ Z), judge whether vertical range maximum value max (△ the Z)≤Engineering Error, if
The judging result be it is yes, then by the member springs back outer mold surface PiCorresponding current die face MiAs springback compensation mold
Type face simultaneously carries out step S300, if the judging result is the die face of otherwise building i+1 time emulation, and repeats institute
Step S100~200 are stated, until described be judged as YES；
Step S300：Component creep age forming mold is established according to the springback compensation die face, to the component
Creep age forming mold carries out mold cooling finite element simulation, obtains rebound thermal expansion die face, and the mold cooling has
Initial temperature is set for the forming temperature of component in the component creep age forming step in limit member emulation and inputs the structure
Temperature lowering curve of the part in the creep age forming step.
Further, the die face step of the i+1 time emulation is constructed：In the i+1 die face with
Z(i+1)j=Zij-Kij*ΔZijFor the Z axis coordinate of each node, wherein KijTime of node j in rear part outer mold surface is compensated for i-th
Bullet amount, Kij=Δ Zij/ΔZj, Δ ZjVertical range of the node j to object type face, the X of node j, Y-axis when for component flat condition
Coordinate is constant.
Further, further include in the step S200：Extract member springs back after external surface and by the external surface with
After the periphery alignment in the object module face, the rebound outer mold surface P after calculating the creep member springs backiEach node is gone up to target
Type face PgoalThe vertical range Δ Z of upper each nodeij。
Further, the creep ageing constitutive model in the MSC.MARC is：
σy=σi+σss+σppt+σdis (2)
In equation (1)It is creep strain rate, A and B indicate material creep first stage parameter, σ0For creep strain threshold
Stress,It is influenced for describing material mobile dislocation to the promotion of creep rate, σyFor the yield strength of material；
σ in equation (2)-(5)iFor intrinsic strength, σssFor solution strengthening, σpptFor precipitation strength, σdisFor dislocation strengthening, Css
For the concentration dependent solution strengthening coefficient of material, cpptIt grows up relevant precipitation strength coefficient for material precipitated phase forming core, n1
For the regulation coefficient of precipitated phase form factor q, CdisFor material dislocation strengthening coefficient, n2For the regulation coefficient of dislocation；
In equation (6)-(9)For precipitated phase relative volume fraction, l is precipitated phase length, and q is precipitated phase form factor,
For opposite dislocation density, C1For material parameter relevant to solutes accumulation, m2And n3Respectively current relative volume fraction and creep
Regulation index of the dislocation density of generation to relative volume fraction change rate, C2For precipitated phase side growth rate related coefficient, m3
And n4Respectively current precipitated phase length and dislocation density are to the regulation index of precipitated phase tensile strain rate, a and b is indicated and stress
Relevant precipitated phase full-size, C3It is precipitated phase in side and the relevant coefficient of disk growth rate, t*For material peak value timeliness
Time, n5And n6Influence coefficient for stress and time to form factor；C4It is creep strain rate and dislocation density to opposite position
The influence coefficient of dislocation density change rate.
Further, the step S100 is further comprising the steps of：
It constructs the theoretical outer mold surface of component or extracts the outer mold surface of component in CATIA as emulation mould type for the first time
Face carries out reverse flattening to component using geometric projection principle and is used as the limit element artificial module；
In MSC.MARC finite element software to component carry out grid dividing, after in MSC.MARC finite element software by mould
Tool type face is set as rigid body, and geometric attribute, material properties, primary condition and boundary condition is arranged.
Compared with the prior art, technical effect of the invention：
The present invention is provided to the springback compensation methods of creep age forming, at present more for creep age forming application
Extensive type face springback compensation algorithm is deviation adjustment method.Deviation adjustment method is by pressing back each node deviation in plate rebound front and back
Bullet opposite direction is applied to die face and compensates.Wherein between the usual value 0.5~1 of compensation factor k, and compensating
Cheng Zhong, the compensation factor k of all nodes are same constant.
However such algorithm does not consider component different location due to knots such as complex curvatures, local reinforcement and boss recess
The inconsistent phenomenon of rebound degree caused by structure leads to the type face for local convergence occurring when the iterative compensation of type face or final compensation comes out
Curvature mutates, and cannot achieve component whole smooth gentle transition, and the member type face distortion after often resulting in forming, precision is not up to
To requirement on machining accuracy.And the present invention is by by compensation factor KijIt is set as the rebound of node j in i-th compensation rear part outer mold surface
Amount, and pass through Δ Zj(vertical range of the node j to object type face when component flat condition) calculate the compensation at each node because
Sub- Kij, fully consider the difference of each node shape of component itself, and springback compensation is carried out according to the structure at each node, thus
Avoid component torsional deformation caused by rebound.Improve the precision of resulting materials component.In compensation process, this method can basis
Specific component is adjusted, and has self-learning capability, and the smooth continuous transition of obtained surface curvature makes component forming surface light
Sliding, precision height.
In existing creep ageing constitutive model, the deformation of creep and ageing strengthening during component creep ageing are not accounted for
Influence of the reciprocation to final tooling type face, while it is swollen since height warms also not account for die face in practical manufacturing process
Variation caused by swollen effect.The method provided by the present invention comprehensively considers that component difference node rebound degree is inconsistent and die face is high
It warms bulking effect weighting to act on the Contrary compensation of forming die face, using finite element method analogue simulation shaping dies from height
Temperature is gradually dropped to the process of room temperature, finally obtains die face at room temperature, and the threedimensional model of mold is established with this type of face.Subtract
It is few while calculate handled data volume, and joined component inside factor in constitutive model, improve springback compensation precision and
Mold design precision.
Provided by the present invention for the springback compensation method of creep age forming, more accurate tooling quasi spline side
Method more can be suitably used for the large-scale component Accurate Shaping with labyrinth feature.This method can reduce mould in actual production process
Has the number that repairs a die, to reduce cost.The method provided by the present invention is particularly suitable for large-scale integral Al-alloy component manufacture.
Provided by the present invention for the springback compensation method of creep age forming, component creep age forming has been fully considered
The deformation of creep and ageing strengthening reciprocation in the process, the type face after springing back iterative compensation are more in line with component practical structures,
Component forming rear profile face precision is also higher.
Provided by the present invention for the springback compensation method of creep age forming, using what is write based on Python
Script file, the script file is run in MSC.MARC finite element software can quickly obtain the point cloud seat in new die type face
Mark improves compensation efficiency, reduces compensation and expends the time.
Specifically please refer to the various embodiments that the springback compensation method according to the present invention for creep age forming proposes
It is described below, will make apparent in terms of above and other of the invention.
Detailed description of the invention
Fig. 1 is schematic process flow diagram of the preferred embodiment of the present invention for the springback compensation method of creep age forming.
Fig. 2 is the vertical range schematic diagram in member springs back type face and object type face in the preferred embodiment of the present invention；
Fig. 3 is formed parts curved surface and target surface contrast schematic diagram in the preferred embodiment of the present invention 1~2, wherein a) is
The component curved surface that die face S (comparative example 1) is shaped, b) it is the component curved surface that die face S2 (embodiment) shapes.
Specific embodiment
The attached drawing constituted part of this application is used to provide further understanding of the present invention, schematic reality of the invention
It applies example and its explanation is used to explain the present invention, do not constitute improper limitations of the present invention.
Include the following steps referring to Fig. 1 provided by the present invention for the springback compensation method of creep age forming：
Step S100：Die face is inputted in MSC.MARC software, establishes limit element artificial module, carries out component creep
After age forming, creep component is obtained；
Step S200：Component outer mold surface after enabling each iterative compensation spring back is Pi(i=0,1,2,3 ..., 0 indicates first
It is secondary to emulate obtained rebound type face), deletion currently emulates the die face M usedi(i=0,1,2,3 ..., 0 indicates to imitate for the first time
The die face inputted when true, i.e. the object type face of component), reading element geometry object type face Pgoal, calculate the creep structure
Rebound outer mold surface P after part reboundiEach node is gone up to object type face PgoalThe vertical range Δ Z of upper each nodeij, Δ ZijIndicate the
Node j to object type face P on i iteration rear part rebound type facegoalVertical range, take vertical range Δ described in each node
ZijVertical range maximum value max (△ Z), judge whether vertical range maximum value max (△ the Z)≤Engineering Error, if
The judging result be it is yes, then by the member springs back outer mold surface PiCorresponding current die face MiAs springback compensation mold
Type face simultaneously carries out step S300, if the judging result is the die face of otherwise building i+1 time emulation, and repeats institute
Step S100~200 are stated, until described be judged as YES；
Step S300：Component creep age forming mold is established according to the springback compensation die face, to the component
Creep age forming mold carries out mold cooling finite element simulation, obtains rebound thermal expansion die face, and the mold cooling has
Initial temperature is set for the forming temperature of component in the component creep age forming step in limit member emulation and inputs the structure
Temperature lowering curve of the part in the creep age forming step.；
Creep age forming process can be carried out by existing method in this method, mainly include：1. load phase, component is put
Setting the progress vacuum load on mold makes component be bonded mold；2. creep ageing stage, component heat-insulation pressure keeping one in autoclave
It fixes time, stress relaxation and creep forming occur for component inside；3. in the stage of rebound, after heat-insulation pressure keeping, component is sprung back.
The completion above three stage completes creep age forming at last.
The method provided by the present invention is increased after creep ageing in temperature-fall period by step S300 in simulation process, temperature
Change the affecting parameters to member type face, so that considering the thermal expansion of high temperature die face into room temperature process in simulation result
Effect increases material itself fuel factor and acts in simulation process in the case where the prior art only considers external factor
Effect improves the precision in gained simulation type face, so that simulation result is more true and reliable.Providing method is made according to the present invention
The component processed of mold, after practical creep ageing, component error change is still able to satisfy Engineering Error requirement.It reduces
Non- part rate, reduces production cost.
For rebound thermal expansion die face, the tooling geometric type that can be obtained according to the type face obtained by the method provided by the present invention
Face thickeies design die face according to geometry profile, then increases the structures such as pedestal, lifting lug and forklift hole in design mold.
Preferably, the die face step of i+1 described in component time emulation：In (i+1) die face with
Z(i+1)j=Zij-Kij*ΔZijFor the Z axis coordinate of each node, wherein KijTime of node j in rear part outer mold surface is compensated for i-th
Bullet amount, Kij=Δ Zij/ΔZj, Δ ZjVertical range of the node j to object type face, the X of node j, Y-axis when for component flat condition
Coordinate is constant.Springback capacity K in the prior artijFor steady state value, and according to node each in creep rear part and target in the present invention
The difference of each node vertical range calculates separately corresponding springback capacity on die face, improves in simulation process to springback process
The specific aim and accuracy of analysis can not accurately be used for so as to avoid existing method with boss sunk structure member springs back
The problem of analysis, improves the accuracy of rebound emulation, improves the computational accuracy of springback compensation.
Preferably, further include in step S200：External surface after extracting member springs back and by the external surface and the mesh
After the periphery alignment for marking model face, the rebound outer mold surface P after calculating the creep member springs backiEach node is gone up to object type face
PgoalThe vertical range Δ Z of upper each nodeij。
Preferably, step S100 is further comprising the steps of：It constructs the theoretical outer mold surface of component or extracts component in CATIA
Outer mold surface as the die face that inputs when emulating for the first time, reverse flattening is carried out to component using geometric projection principle and is used as institute
State limit element artificial module；
In MSC.MARC finite element software to component carry out grid dividing, after in MSC.MARC finite element software by mould
Tool type face is set as rigid body, and geometric attribute, material properties, primary condition and boundary condition is arranged.
Preferably, the creep ageing constitutive model in the MSC.MARC is：
σy=σi+σss+σppt+σdis (2)
In equation (1)It is creep strain rate, A and B indicate material creep first stage parameter, σ0For creep strain threshold
Stress,It is influenced for describing material mobile dislocation to the promotion of creep rate, σyFor the yield strength of material；
σ in equation (2)-(5)iFor intrinsic strength, σssFor solution strengthening, σpptFor precipitation strength, σdisFor dislocation strengthening, Css
For the concentration dependent solution strengthening coefficient of material, cpptIt grows up relevant precipitation strength coefficient for material precipitated phase forming core, n1
For the regulation coefficient of precipitated phase form factor q, CdisFor material dislocation strengthening coefficient, n2For the regulation coefficient of dislocation；
In equation (6)-(9)For precipitated phase relative volume fraction, l is precipitated phase length, and q is precipitated phase form factor,
For opposite dislocation density, C1For material parameter relevant to solutes accumulation, m2And n2Respectively current relative volume fraction and creep
Regulation index of the dislocation density of generation to relative volume fraction change rate, C2For precipitated phase side growth rate related coefficient, m3
And n4Respectively current precipitated phase length and dislocation density are to the regulation index of precipitated phase tensile strain rate, a and b is indicated and stress
Relevant precipitated phase full-size, C3It is precipitated phase in side and the relevant coefficient of disk growth rate, t*For material peak value timeliness
Time, n5And n6Influence coefficient for stress and time to form factor；C4It is creep strain rate and dislocation density to opposite position
The influence coefficient of dislocation density change rate.
Creep ageing constitutive model in the method provided by the present invention, by the macro microcosmic unification of the creep ageing under material therefor high temperature
Creep strain is associated with yield strength in constitutive model, and yield strength and microstate variable association, therefore appropriate in this structure
The coupled relation of creep strain, yield strength and microstate variable is established, component is strong with material during the deformation of creep
Interactional effect is spent to be characterized.Relevant parameter can be by being uniaxially stretched creep test curve and micro- in constitutive model
Transmission electron microscope statistical data is seen to be fitted to obtain.
As shown in Figure 1, the present invention, which provides, to be included the following steps for the springback compensation specific method of creep age forming：
(1) based on the component creep age forming finite element simulation of MSC.MARC commercialization finite element software
A. it constructs the theoretical outer mold surface of component or extracts emulation for the first time of the outer mold surface of component as mold in CATIA
With die face, reverse flattening is carried out to component using geometric projection principle and is used as finite element simulation component, and saves as .stp
Format.
B. initial simulation mold type face and component are read in MSC.MARC finite element software, and grid then is carried out to component
It divides, die face is set as rigid body, while the information such as geometric attribute, material properties, primary condition and boundary condition are arranged.
C. input description component high-temperature becomes second nature the creep ageing constitutive model subprogram of variation, creep ageing this structure mould
Type is：
σy=σi+σss+σppt+σdis (2)
Equation (1) is creep strain rateEvolution model, wherein A and B indicate material creep first stage parameter, σ0For
Creep strain threshold stress, as applied stress σ >=σ0Creep strain occurs, does not otherwise occur (i.e.),It is used to
Describing material mobile dislocation influences the promotion of creep rate, σyFor the yield strength of material.Equation (2)-(5) indicate that material is compacted
Become the intensity evolution model in ag(e)ing process, wherein yield strength σyBy intrinsic strength σi, solution strengthening σss, precipitation strength σppt
With dislocation strengthening σdisComposition.C in formulassFor the concentration dependent solution strengthening coefficient of material, cpptFor material precipitated phase forming core
It grows up relevant precipitation strength coefficient, n1For the regulation coefficient of precipitated phase form factor q, CdisFor material dislocation strengthening coefficient, n2
For the regulation coefficient of dislocation.Equation (6)-(9) indicate microstate (precipitated phase relative volume fraction in material creep ag(e)ing processPrecipitated phase length l, precipitated phase form factor q and opposite dislocation density) variable evolution model, it is mainly used for describing in material
The variation of portion's microstructure.C in formula1For material parameter relevant to solutes accumulation, m2And n3Respectively current relative volume fraction
Regulation index of the dislocation density generated with creep to relative volume fraction change rate；C2For precipitated phase side growth rate correlation
Coefficient, m3And n4The regulation index of respectively current precipitated phase length and dislocation density to precipitated phase tensile strain rate, a and b table
Show precipitated phase full-size relevant to stress；C3It is precipitated phase in side and the relevant coefficient of disk growth rate, t*For material
Peak aging time, n5And n6Influence coefficient for stress and time to form factor；C4For creep strain rate and dislocation density
To the influence coefficient of opposite dislocation density change rate.Creep is answered in the macro microcosmic sand stone concrete of creep ageing under material at high temperature
Change is associated with yield strength, and yield strength and microstate variable association, therefore is appropriately established creep strain in this structure, bent
The coupled relation of intensity and microstate variable is taken, the deformation of creep and the intensity effect of influencing each other of component are characterized.This
Relevant parameter can be fitted by being uniaxially stretched creep test curve and microcosmic transmission electron microscope statistical data in structure model
It arrives.
(2) the die face weighting rebound iterative compensation process based on FEM Numerical Simulation
A. creep age forming terminates rear part and springs back, and the component outer mold surface after enabling each iterative compensation spring back is Pi
(i=0,1,2,3 ..., 0 indicates the rebound type face emulated for the first time), deletes current simulation mold type face Mi(i=0,1,2,
3 ..., 0 indicates die face when emulating for the first time), reading element geometry object type face Pgoal；
B. member springs back outer mold surface PiWith object type face PgoalBoth ends alignment, runs the script file of Python editor,
Calculate member springs back outer mold surface PiUpper node j (j indicates the grid node number on member type face) arrives object type face PgoalIt is vertical
Distance, delta Zij,ΔZijIndicate that node j is to the vertical range in object type face, such as Fig. 2 on i-th iteration rear part rebound type face.
C. the new die type face of next iteration emulation is constructed, the Z axis coordinate of node j is Z on new die type face(i+1)j
=Zij-Kij*ΔZij, wherein KijThe springback capacity of node j in rear part outer mold surface, K are compensated for i-thij=Δ Zij/ΔZj,ΔZj
For node j to the vertical range in object type face, the X of node j, Y axis coordinate are constant when for component flat condition；
D. step c is obtained into new die type millet cake cloud coordinate and saves as .stl format, point cloud coordinate file is input to CATIA
Middle carry out surface reconstruction, to obtain new die type face；
F. repetitive process (1) and (2) are until member type face maximum distance Δ Z vertical with object type facemaxLess than or equal to engineering
The error amount of permission.
(3) consider the Contrary compensation process of die material type face thermal expansion effects
It has been obtained finally meeting the die face in formed parts object type face according to process (1) and (2), and has thought to obtain at this time
The die face arrived is the die face after practical forming high-temperature heat expansion.Component creep is established according to the type face after springback compensation
Age forming die is input to MSC.MARC finite element software, carries out grid division, and it is actual component that initial temperature, which is arranged,
Forming temperature；Input temperature lowering curve, the die face that type face after mold is cooled to room temperature as finally needs.
The method provided by the present invention is illustrated below in conjunction with specific embodiment.
Component condition handled by comparative example and embodiment：
Using component object type face as emulation die face for the first time, typical grid band rib component finite element model is established.
Die face is set as rigid body in the present embodiment, and component is by No. 75 quadrilateral units and No. 138 triangular element groups
At.Construction material is 2219 aluminium alloys, material properties：Elasticity modulus 70800MPa, Poisson's ratio 0.33；Overall dimensions are
435.0mm long × 293.7mm wide × 17mm high, wherein equilateral triangle rib (14.4mm high × 5mm is thick) is evenly distributed on structure
Part surface.Coefficient of friction between component and die face is set as 0.3.
Comparative example：Existing springback compensation method die face optimization
Existing mold type face rebound iteration compensation method includes the following steps：
(1) FEM calculation is carried out to creep age forming process based on ABAQUS finite element software
A. target member outer surface is extracted in CATIA as object type face Pgoal, die face Mi(i=0,1,2 ...,
Indicate that die face is object type face p as i=0goal), the planar plate members after expansion are P, and save as * .iges file；
B. mold M is read in finite element analysis softwareiThe iges file of (i=0,1,2 ...) and the iges of component P
File；
C. by mold Mi(i=0,1,2 ...) is set as rigid body, and component P is set as deformable body, respectively to component P and mold
Mi(i=0,1,2 ...) carry out grid dividing；
D. each unit that creep strain material model assigns component P is formed into finite element model, wherein creep strain material
Expect that Norton-Baliley Creep Equation can be selected in model, equation form is as follows：εc=A σmtn；
Wherein, A and m, n are material constants related with temperature, and m is greater than 1, n and is greater than 0 less than or equal to 1, they can be by not
It is determined with uniaxial creep stress strain curve of the stress at a temperature of.Creep drawing is carried out according to metal creep stretching and duration running method
Test is stretched, and test data is fitted using least square method, obtains A and m, n value；
E. component P and mold M during creep age formingiIt is rubbed mould between (i=0,1,2 ...) using Coulomb
Type, coefficient of friction 0.3.It need to be by component P and mold M when springback calculationiContact between (i=0,1,2 ...) is cancelled.
F. creep age forming finite element modelling, the component F after being shaped are carried outi(i=0,1,2 ...)；
(2) new die face is determined
G. mold M is read iniFinite element grid file, the target forming surface P of (i=0,1,2 ...)goalFinite element grid text
Component F after part and formingiThe finite element grid file of (i=0,1,2 ...)；
H. rebound rear part F is calculatedi(i=0,1,2 ...) and target forming surface PgoalShape gap delta, that is, spring back after structure
Normal distance between part and target member；
I. shape gap delta is calculated by the following method：Die face MiThe normal of (i=0,1,2 ...) node is to returning
Play rear part Fi(i=0,1,2 ...) (set the distance is δ to distance1) and the normal to target forming surface Pgoal(setting should for distance
Distance is δ2) difference, i.e., forming rear part FiGap delta=δ of (i=0,1,2 ...) and target forming surface1-δ2。
J. if rebound rear part FiThe maximal clearance δ of (i=0,1,2 ...) and object type facemaxLess than or equal to engineering
Allow tolerance, then terminates, output mask MiThe node data of (i=0,1,2 ...)；Otherwise enter in next step；
K. to mold MiThe type face (i=0,1,2 ...) is modified；
L. it is to the modification method of die face：Along the mold normal direction with δ in penalty coefficient be the position k=0.9
New node is generated, this is to correct rear mold Mi+1The node of (i=0,1,2 ...).To mold Mi(i=0,1,2 ... } it is all
The space coordinate of node is modified, and can get revised new die Mi+1(i=0,1,2 ...)；
M. using revised mold as new die Mi+1(i=0,1,2 ...) repeats (a)~(g) step until gap meets
Admissible tolerance；
(3) die face indicated in the form of mesh point coordinate is input in catia software, is used
QuickSurface Reconstruction function carries out surface fitting, finally exports revised die face；
(4) creep age forming tooling is established according to the die face modified above；
According to above method step, and it is 0.5mm, this structure of Norton-Baliley creep that maximum operation form error, which is arranged,
Equation parameter measures as shown in table 1.Springback compensation is carried out to die face to obtain：Pass through formed parts and target after 5 iteration
Member profile face maximum form error is 0.21mm, finally obtains and compares die face and referred to as S.
1 power law creep constitutive model material parameter table of table
| A | m | n |
| 3.83e-8 | 5.64 | 0.453 |
Embodiment：Springback compensation method die face for creep age forming optimizes
The present invention is provided to the springback compensation methods of creep age forming, illustrate referring to specific method.Constitutive model material
Expect that parameter carries out Inversion Calculation using genetic algorithm.Engineering allows maximum form error to be 0.5mm, parameter in creep constitutive model
As shown in table 2.By the step in specific method, die face optimization is carried out after the parameter in table 2 is brought into.
The material parameter table of creep constitutive model in 2 the method provided by the present invention of table
| A | B | σ0 | σi | Css | Cppt | Cdis | C1 | C2 | C3 | C4 | k1 | k2 | k3 |
| 0.95 | 0.14 | 15.4 | 111.2 | 70.3 | 79.1 | 125.1 | 3.7e-6 | 1.0 | 141.9 | 271.8 | 1.63 | 0.38 | 0.56 |
| k4 | n1 | n2 | n3 | n4 | n5 | n6 | m1 | m2 | m3 | a | b | t* | -- |
| 0.01 | 0.22 | 0.05 | 5.0 | 4.68 | 0.17 | 0.1 | 3.2 | 0.55 | 0.60 | 94.0 | -0.1 | 11 | -- |
It is that 0.16mm obtains mould type that the method provided by the present invention, which first passes through 3 iteration and obtains maximum form error, in embodiment
Face S1 (springback compensation die face)；Continue after carrying out step S300 (or step 3)) to die face S1, gained type face is denoted as
Die face S2 (rebound thermal expansion die face).
According to comparative example die face S and embodiment die face S2, the creep age forming component 1 in autoclave respectively
With component 2, component 1 is identical with 2 experiment condition testing conditions of component：Component vacuum bag is sealed, and technological parameter is set as into
165 DEG C of shape temperature, pressure inside the tank 0.6MPa and heat-insulation pressure keeping 8h.After heat-insulation pressure keeping, autoclave carries out cooling release, cold
To 50 ° or so taking-up formed parts.
Using the practical curved surface of ATOS optical three-dimensional measurement instrument scanning formed parts and in ProfessionalAtos software
It is compared with target surface, acquired results such as Fig. 3.
Pass through a) and b) finding in comparison chart 3：After creep ageing, the component come is shaped using die face S
The worst error of curved surface and target surface is 0.90mm, needs further to repair a die to test again and be verified.And it is mentioned using the present invention
The worst error that the die face S2 obtained for method shapes the component curved surface and target surface that come is 0.32mm, is less than engineering
Error 0.5mm.
By comparative example and comparative example it is found that the springback compensation side provided by the present invention for creep age forming
Method, it is only necessary to precision being reduced as a result, calculating time-consuming higher than existing optimization method can be obtained for iteration 3 times.
Pass through the result of component 1 and component 2 obtained by comparison die face S and die face S2：Weighting rebound is not considered
Shaping the component curved surface relative target wrap-around error come with the die face S of temperature compensation has been more than Engineering Error, and is returned
Bullet thermal expansion die face S2 shapes the component curved surface relative target wrap-around error come and is less than Engineering Error.
Due to considering the fuel factor of mold body, structure that the mold that providing method obtains according to the present invention is processed
Part, after cooling, worst error is able to satisfy engineering processing request.And illustrate that method precision provided by the invention is higher, subtracts indirectly
The small number that repairs a die reduces the rejection rate of component in production, reduces production cost.
Those skilled in the art will be clear that the scope of the present invention is not limited to example discussed above, it is possible to carry out to it
Several changes and modification, the scope of the present invention limited without departing from the appended claims.Although oneself is through in attached drawing and explanation
The present invention is illustrated and described in book in detail, but such illustrate and describe is only explanation or schematical, and not restrictive.
The present invention is not limited to the disclosed embodiments.
By to attached drawing, the research of specification and claims, those skilled in the art can be in carrying out the present invention
Understand and realize the deformation of the disclosed embodiments.In detail in the claims, term " includes " is not excluded for other steps or element,
And indefinite article "one" or "an" be not excluded for it is multiple.The certain measures quoted in mutually different dependent claims
The fact does not mean that the combination of these measures cannot be advantageously used.Any reference marker in claims is not constituted pair
The limitation of the scope of the present invention.
Claims (5)
1. a kind of springback compensation method for creep age forming, which is characterized in that include the following steps：
Step S100：Die face is inputted in MSC.MARC software, establishes limit element artificial module, carries out component creep ageing
After forming, creep component is obtained；
Step S200：Component outer mold surface after enabling each iterative compensation spring back is Pi(i=0,1,2,3......, 0 indicates to imitate for the first time
The rebound type face really obtained), deletion currently emulates the die face M usedi(i=0,1,2,3......, 0 indicates to emulate for the first time
When the die face that inputs, i.e. the object type face of component), reading element geometry object type face Pgoal, calculate the creep component
Rebound outer mold surface P after reboundiEach node is gone up to object type face PgoalThe vertical range Δ Z of upper each nodeij, Δ ZijIndicate i-th
Node j to object type face P on secondary iteration rear part rebound type facegoalVertical range, take vertical range Δ described in each node
ZijVertical range maximum value max (Δ Z), judge whether vertical range maximum value max (Δ the Z)≤Engineering Error, if
The judging result be it is yes, then by the member springs back outer mold surface PiCorresponding current die face MiAs springback compensation mold
Type face simultaneously carries out step S300, if the judging result is the die face of otherwise building i+1 time emulation, and repeats institute
Step S100~200 are stated, until described be judged as YES；
Step S300：Component creep age forming mold is established according to the springback compensation die face, to the component creep
Age forming die carries out mold cooling finite element simulation, obtains rebound thermal expansion die face, the mold cooling finite element
It is the forming temperature of component and to input the component in the component creep age forming step and exist that initial temperature is arranged in emulation
Temperature lowering curve in the creep age forming step.
2. the springback compensation method according to claim 1 for creep age forming, which is characterized in that building described the
The die face step of i+1 emulation：With Z in the i+1 die face(i+1)j=Zij-Kij*ΔZijFor each node
Z axis coordinate, wherein KijThe springback capacity of node j in rear part outer mold surface, K are compensated for i-thij=Δ Zij/ΔZj, Δ ZjFor component
For node j to the vertical range in object type face, the X of node j, Y axis coordinate are constant when flat condition.
3. the springback compensation method according to claim 1 for creep age forming, which is characterized in that the step
Further include in S200：Extract member springs back after external surface and the external surface is aligned with the periphery in the object module face
Afterwards, the rebound outer mold surface P after calculating the creep member springs backiEach node is gone up to object type face PgoalUpper each node it is vertical away from
From Δ Zij。
4. the springback compensation method according to claim 1 for creep age forming, which is characterized in that described
Creep ageing constitutive model in MSC.MARC is：
σy=σi+σss+σppt+σdis (2)
In equation (1)It is creep strain rate, A and B indicate material creep first stage parameter, σ0For creep strain threshold stress,It is influenced for describing material mobile dislocation to the promotion of creep rate, σyFor the yield strength of material；
σ in equation (2)-(5)iFor intrinsic strength, σssFor solution strengthening, σpptFor precipitation strength, σdisFor dislocation strengthening, CssFor material
Expect the relevant solution strengthening coefficient of solute concentration, cpptIt grows up relevant precipitation strength coefficient for material precipitated phase forming core, n1For analysis
The regulation coefficient of phase form factor q out, CdisFor material dislocation strengthening coefficient, n2For the regulation coefficient of dislocation；
In equation (6)-(9)For precipitated phase relative volume fraction, l is precipitated phase length, and q is precipitated phase form factor,For phase
To dislocation density, C1For material parameter relevant to solutes accumulation, m2And n3Respectively current relative volume fraction and creep generate
Regulation index of the dislocation density to relative volume fraction change rate, C2For precipitated phase side growth rate related coefficient, m3And n4
To the regulation index of precipitated phase tensile strain rate, a and b indicate related to stress for respectively current precipitated phase length and dislocation density
Precipitated phase full-size, C3It is precipitated phase in side and the relevant coefficient of disk growth rate, t*When for material peak value timeliness
Between, n5And n6Influence coefficient for stress and time to form factor；C4It is creep strain rate and dislocation density to opposite dislocation
The influence coefficient of rate of change of the density.
5. the springback compensation method according to claim 1 for creep age forming, which is characterized in that the step
S100 is further comprising the steps of：
It constructs the theoretical outer mold surface of component or extracts the outer mold surface of component in CATIA as emulation die face for the first time, benefit
Geometric projection principle is used to carry out reverse flattening as the limit element artificial module to component；
In MSC.MARC finite element software to component carry out grid dividing, after in MSC.MARC finite element software by mould type
Face is set as rigid body, and geometric attribute, material properties, primary condition and boundary condition is arranged.
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