CN106055769A - Performance recognition method of bolt interfaces under different tightening torques - Google Patents

Abstract

The invention discloses a method of recognizing interface performance of bolt overlapping structures under different tightening torques by utilizing structure optimization technology. The method comprises following steps: 1), setting up a finite element model of to-be-connected parts according to a geometric model; 2), utilizing an orthotropic and anisotropic thin-layer unit to set a model for interfaces among to-be-connected parts in order to obtain analysis mode frequency; 3), carrying out a modal test to connecting structures under different tightening torques in order to obtain modal frequency under different tightening torques; 4) utilizing structure optimization technology and adopting modal frequency with different tightening torques to recognize elasticity parameters of thin-layer units such that interface performance descriptions of bolt connecting structures are obtained under different tightening torques. The method of recognizing interface performance of bolt connecting structures under different tightening torques by utilizing structure optimization technology has following beneficial effects: an effective method for accurately simulating connecting structures of bolt overlapping structures is provided so that elasticity parameters for connecting interfaces under different tightening torques in a test can be obtained; a changing rule for bolt connecting interface performance under different tightening torques is obtained so that the method is of engineering significance.

Description

Bolt interface performance recognition methods under different pre-fastening moments

Technical field

The present invention relates to a kind of interface performance recognition methods, be specifically related to a kind of different pre-fastening moments based on optimisation technique Lower bolt interface performance recognition methods.

Background technology

Bolt overlap joint, as a kind of typical case's type of attachment in being mechanically connected, is widely used in the assembling of engineering structure even In connecing.Attachment structure can produce multiple mechanics effect under pre-fastening moment effect, such as bonding, microcosmic sliding and macroslip.Thin Layer unit belongs to the one of interracial contact unit, has been applied to welding, bolt connection etc. and has been mechanically connected the pretightning force of form Non-linear phenomena under square carries out linearization process.

When carrying out bolt fastening structure finite element analysis, node is traditionally used to overlap, connect the modelings such as spring Method.Test exists and is difficult to obtain the problem of linkage interface elastic parameter under different pre-fastening moment, cause carrying out difference How the research of the Changing Pattern of bolt linkage interface performance under pretightning force, design a kind of effective and feasible based on optimisation technique Bolt interface performance recognition methods under different pre-fastening moments, it has also become technical problem urgently to be resolved hurrily

Summary of the invention

Goal of the invention: in order to overcome the deficiencies in the prior art, the different pre-fastening moment shadow to linkage interface of research Ringing and identify the mechanical property at attachment structure interface, the present invention uses the method that numerical simulation, test and optimisation technique combine Analyze, establish bolt interface performance recognition methods under a kind of effective and feasible based on optimisation technique different pre-fastening moments.

Technical scheme: for solving above-mentioned technical problem, under the different pre-fastening moments that the present invention provides, bolt interface performance is known Other method, comprises the following steps:

Step 1, sets up the FEM (finite element) model of connected piece according to the geometric model of bolt bridging arrangement, and described bolt overlaps Structure includes that overlapped part and bolt connection piece, described overlapped part include upper and lower lapping plate；

Step 2, utilizes Orthotropic Thin layer unit to be modeled the interface between connected piece, described thin layer element Modeling is a kind of equivalent description method of interface performance, because in the face of bolt fastening structure joint face, the outer performance of dough-making powder is inconsistent, Use orthotropic material constitutive relation, analyze model at this on the basis of, obtain the Analysis Mode of bolt bridging arrangement Frequency；

Step 3, carries out modal test to the attachment structure under different pre-fastening moments, it is thus achieved that the mode under different pre-fastening moments Frequency；

Step 4, utilizes structure optimization technology, uses the model frequency under different pre-fastening moment, the elasticity to thin layer element Parameter is identified, thus the bolt fastening structure interface performance obtained under different pre-fastening moment describes.

Wherein, the interface between connected piece is built by above-mentioned steps 2 according to described Orthotropic Thin layer unit Mould, including following basic step:

2.1) pre-fastening moment region is determined: according to bolted characteristic, bolt hole local stiffness should be greater than away from bolt The rigidity in the region near hole, the local strengthening region of pre-fastening moment effect is square area, length of side a=of square area 2D；

2.2) thin layer element material parameter is determined: described orthogonal respectively have 9 independent material parameters to material, respectively It it is Young's modulus E in 3 directions₁₁, E₂₂, E₃₃, Poisson's ratio v₁₂, v₂₃, v₃₁With 3 shear modulus G₁₂, G₂₃, G₃₁.Root thin layer element Basic assumption plane internal strain tend to 0, i.e. ε_x=ε_y=ε_xy≈ 0, then according to the basic reason of orthogonal anisotropy thin layer element Material constitutive equation after opinion can be degenerated is

$\left\{\begin{array}{c}{\mathrm{\σ}}_{zz}\\ {\mathrm{\τ}}_{yz}\\ {\mathrm{\τ}}_{zx}\end{array}\right\}=\left[\begin{array}{ccc}{E}_{33}& 0& 0\\ 0& G_{23}& 0\\ 0& 0& G_{31}\end{array}\right]\left\{\begin{array}{c}{\mathrm{\ϵ}}_{zz}\\ {\mathrm{\γ}}_{yz}\\ {\mathrm{\γ}}_{zx}\end{array}\right\}---\left(1\right)$

Each parameter σ in formula (1)_zz, τ_yz, τ_zx, ε_zz, γ_yz, γ_zxRepresent z yz direction and zx outside direct stress, face respectively Direction shearing stress, z is yz direction and the shearing strain of zx direction outside normal strain, face.E₃₃, G₂₃And G₃₁It is respectively z yz direction outside, face With zx direction elastic parameter.Have only to given E₃₃, G₂₃And G₃₁Initial value, it is possible to realize the mechanical property table of thin layer element Levy.

2.3) thin layer element thickness is determined: determined the thickness of thin layer element by definition proportionality coefficient r:

$r=\frac{max(l_1,l_2)}{d}---\left(2\right)$

L in formula (2)₁, l₂Represent the length of thin layer element, width and thickness respectively with d, the value of r is usually 50.

2.4) to the bolt lapping plate utilizing solid element to set up and utilize Orthotropic Thin layer unit to be set up The FEM (finite element) model at bolt overlap joint interface carries out model analysis, obtains Analysis Mode frequency.

Wherein, theoretical according to mode experiment in above-mentioned steps 3, the bolt bridging arrangement under different pre-fastening moments is carried out certainly By the dynamic characteristic test under state, obtaining the model frequency under its different pre-fastening moments, its basic step includes:

3.1) utilize the hammering method in modal test, structure is carried out dynamic test, on axis, defines hammering in the structure Point, and at the hammer point of first, border, define a pick-up point；

3.2) with rubber rope, bolt lapping plate is hung, make free boundary structure；With glue, vibration pickup is cohered In selected pick-up point position, border；

3.3) with wire, pulse hammer and vibration pickup are accessed the corresponding interface of signal sampler；

3.4) utilize the model analysis module of pilot system, model analysis parameter is set；

3.5) structurally each impacting point edge is applied node impulsive force from direction, face by pulse hammer, gather each measuring point Input when receiving pulse excitation and output signal；

3.6) with the signal analyzer of pilot system, input/output signal is done fast Fourier transform, obtain the frequency of system Ring function, then obtained the model frequency of system by curve matching.

Wherein according to structure optimization technology in step 4, use the model frequency under different pre-fastening moment, step 2 is built The elastic parameter of vertical thin layer element is identified, thus the bolt fastening structure interface performance obtained under different pre-fastening moment is retouched Stating, its basic step includes:

4.1) parameter to be optimized is determined: to the Orthotropic Thin layer list describing bolt overlap joint interface performance set up Meta-model, according to step 2.1) obtained by three elastic parameters E₃₃, G₂₃And G₃₁As parameter to be optimized；

4.2) objective optimization function is determined: the Modal Test to the bolt bridging arrangement under obtained different pre-fastening moments Frequency, the test value obtained according to step 3, for the Modal Test frequency under each pre-fastening moment, the target being defined below is excellent Change function:

$\left\{\begin{array}{c}MinJ\left(p\right)=|{\mathrm{freq}}^e-{\mathrm{freq}}^a\left(p\right){|}_2^2\\ s.t.p_1\≤p\≤p_2\end{array}\right.---\left(3\right)$

Freq in formula (3)^eAnd freq^aRepresenting Modal Test frequency and the vector of Analysis Mode frequency composition respectively, p represents Parameter vector to be optimized, the physical meaning of this object function is: at the excursion [p of parameter₁p₂In], find the most optimized parameter Make Modal Test frequency and 2 Norm minimums of Analysis Mode frequency vector difference；

4.3) parameters optimization scope is determined: according to experimental rules and mechanics basic relational expression, obtain the change of parameter to be optimized Change scope [p₁p₂]；

4.4) utilize iteration optimization algorithms, to step 4.2) obtained by object function be optimized, finally try to achieve optimum Parameter, thus obtain describing the elastic parameter of the Orthotropic Thin layer unit of the bolt interface performance under each pre-fastening moment Value, thus obtain the mechanics parameter of bolt interface performance.

During use, it would however also be possible to employ the following step enforcement said method simplified:

Step 1, sets up the FEM (finite element) model of connected piece according to geometric model；

Step 2, by the thin layer element of orthotropic material, is simulated the interface of bolt bridging arrangement, To analyzing model；

Step 3, utilizes modal test system, and the bolt bridging arrangement under different pre-fastening moments is carried out Free Modal examination Test, obtain structural test model frequency；

Step 4, in conjunction with optimisation technique, is identified by material parameter orthotropic to thin layer element, to protect Card analyzes 2 Norm minimums of frequency and Modal Test frequency vector difference.

Beneficial effect: the invention provides bolt interface under a kind of different pre-fastening moments based on Structure dynamic characteristics optimization Performance recognition methods, the form using finite element analysis to combine with dynamic test, establish under different pre-fastening moment spiral shell The Orthotropic Thin layer unit modeling method of bolt lapping plate interface performance, simultaneously by structure dynamic characteristic objective optimization letter Number, identifies the mechanics parameter at bolt lapping plate interface under different pre-fastening moment, has highly important engineering significance.

The present invention combines numerical simulation, test and optimisation technique, it is possible to the interface performance of bolt fastening structure is carried out mould Intend, and optimisation technique can be utilized to accurately identify the interface performance parameter of the bolt fastening structure under different pre-fastening moment.Consider Pre-fastening moment is relatively low on the impact of interface in-plane mechanical properties, and thin layer element has all directions in face and strains the spy gone to zero Point, uses the orthogonal anisotropy material constitutive relation degenerated to thin layer element assignment, and the method can analyze connector not With the deformation of its contact surface under pre-fastening moment and stress characteristics, and by optimisation technique, use Modal Test frequency as target Value, it is possible to consider the mechanical property variation tendency of bolt lapping plate contact interface under different pre-fastening moment, provide for engineer applied A kind of accurately based on numerical simulation, the linkage interface performance recognition methods testing and optimize.

Except invention described above solves the technical problem that, constitutes the technical characteristic of technical scheme and by these skills Outside the advantage that the technical characteristic of art scheme is brought, bolt interface performance recognition methods institute energy under the different pre-fastening moments of the present invention The advantage that the other technologies feature comprised in the other technologies problem of solution, technical scheme and these technical characteristics bring, will It is described in more detail in conjunction with accompanying drawing.

Accompanying drawing explanation

Fig. 1 is the bolt lapping plate geometric model of the embodiment of the present invention；

Fig. 2 is bolt lapping plate finite element analysis model；

Fig. 3 is bolt lapping plate mode experiment test model；

Fig. 4 is bolt lapping plate mode experiment system；

Fig. 5 is pre-fastening moment zone of action thin layer element elastic parameter E₃₃With pre-fastening moment relation recognition result figure；

Fig. 6 is pre-fastening moment zone of action thin layer element elastic parameter G₂₃With pre-fastening moment relation recognition result figure；

Fig. 7 is pre-fastening moment zone of action thin layer element elastic parameter G₃₁With pre-fastening moment relation recognition result figure；

Fig. 8 is weak contact area thin layer element elastic parameter E₃₃With pre-fastening moment relation recognition result figure；

Fig. 9 is weak contact area thin layer element elastic parameter G₂₃With pre-fastening moment relation recognition result figure；

Figure 10 is weak contact area thin layer element elastic parameter G₃₁With pre-fastening moment relation recognition result figure.

Detailed description of the invention

Embodiment:

Bolt linkage interface performance recognition methods under the different pre-fastening moments based on optimization of the present embodiment, including following step Rapid:

(1) according to the geometric model of the structure of bolt lapping plate shown in Fig. 1, use solid element, set up the letter of connected piece Change FEM (finite element) model, as in figure 2 it is shown, this connected piece includes two pieces of upper and lower lapping plates.The geometric parameter of this model such as Fig. 1 institute Showing, its geometry and physical parameter are as follows:

Two blocks of connected plates all use aluminum alloy materials, diameter of bolt hole D=10mm.Aluminium alloy mechanics parameter is: elastic Modulus E=6.87 × 10¹⁰Pa, Poisson's ratio μ=0.33, density p=2800kg/m³, the pre-fastening moment T of applying on bolt_NValue For 2N m, 4N m, 6N m, 7N m, 10N m, 12N m, 14N m, 16N m, 18N m, 20N m, 22N m, 25N m, 28N m.

(2) according to described Orthotropic Thin layer unit modeling method, contact interface is modeled, obtains such as Fig. 2 Shown analysis finite element model, thin layer element is located between two pieces of upper and lower lapping plates, and its basic step includes:

Step (2.1), determine pre-fastening moment region: bolt hole local stiffness should be greater than the region near away from bolt hole Rigidity, the local strengthening square area length of side of pre-fastening moment effect is a=2D=20mm；

Step (2.2), pretightning force by being connected the material properties of plate, determine orthogonal anisotropy thin layer element to bolt Original material parameter.Understanding according to step (2.1), interface thin layer element is divided into two groups, and one group is pretightning force effect equivalence district TerritoryOne group is the weak contact area away from pretightning force effect

Step (2.3), determine thin layer element thickness: determined the thickness of thin layer element by definition proportionality coefficient r:

$r=\frac{max(l_1,l_2)}{d}---\left(0.1\right)$

Wherein l₁, l₂Represent the length of thin layer element, width and thickness respectively with d, the value of r is 50.

Step (2.4), to the bolt lapping plate utilizing solid element to set up with utilize Orthotropic Thin layer unit institute The FEM (finite element) model at the bolt overlap joint interface set up carries out model analysis, obtains Analysis Mode frequency.

(3) theoretical according to mode experiment, carry out the bolt bridging arrangement under different pretightning forces under free state is dynamic Attribute testing, obtains the model frequency under its different pretightning forces, and its basic step includes:

(3.1) utilize the hammering method in modal test, structure is defined 13 hammer points, and in the hammering of first, border A pick-up point is defined, as shown in Figure 3 at Dian；

(3.2) with rubber rope, bolt lapping plate is hung, make free boundary structure；With glue, vibration pickup is cohered In selected pick-up point position, border, as shown in Figure 4, wherein 1 representing rubber rope, 2 represent acceleration transducer, and 3 represent calculating Machine, 4 represent analyser, and 5 represent data collecting instrument, and 6 represent impulsive force hammer；

(3.3) with wire, pulse hammer and vibration pickup are accessed the corresponding interface of signal sampler, as shown in Figure 4；

(3.4) utilize the model analysis module of pilot system, model analysis parameter is set；

(3.5) structurally each impacting point edge is applied node impulsive force from direction, face by pulse hammer, gather each survey Put the input when receiving pulse excitation and output signal；

(3.6) with the signal analyzer of pilot system, input/output signal is done fast Fourier transform, then by song Line matching obtains the model frequency of structure, as shown in table 1.

Table 1

(4) according to structure optimization technology, using the model frequency under different pretightning force, that is set up step (2) is orthogonal The elastic parameter of anisotropy thin layer element is identified, thus obtains the bolt fastening structure interface performance under different pretightning force Describing, its step includes:

(4.1) parameter to be optimized is determined: to the Orthotropic Thin layer describing bolt overlap joint interface performance set up Two groups of elastic parameters that model of element obtainsWithAs parameter to be optimized；

(4.2) objective optimization function is determined: the test mould to the bolt bridging arrangement under obtained different pre-fastening moments State frequency, for pre-fastening moment T_NValue is respectively 2N m, 4N m, 6N m, 7N m, 10N m, 12N m, 14N m, The model frequency of 16N m, 18N m, 20N m, 22N m, 25N m, 28N m, the objective optimization function being defined below:

$\left\{\begin{array}{c}MinJ\left(p\right)=|{\mathrm{freq}}^e-{\mathrm{freq}}^a\left(p\right){|}_2^2\\ s.t.p_1\≤p\≤p_2\end{array}\right.---\left(0.2\right)$

Treat parameters optimization vector p, at the excursion [p of parameter₁p₂In], find optimized parameter and make Modal Test frequency Rate and 2 Norm minimums of Analysis Mode frequency vector difference.

(4.3) determine parameters optimization scope: according to experimental rules and mechanics basic relational expression, use perturbation method, treated Excursion [the p of parameters optimization₁p₂], generally take p1=0.1～0.01p, p2=10～100p.

(4.4) utilize iteration optimization algorithms, obtain pre-fastening moment T_NValue is respectively 2N m, 4N m, 6N m, 7N During m, 10N m, 12N m, 14N m, 16N m, 18N m, 20N m, 22N m, 25N m, 28N m, bolt circle is described The elastic parameter of the Orthotropic Thin layer unit of face performanceWithValue, the optimization obtained Result is as shown in Fig. 5～10

Above in association with accompanying drawing, embodiments of the present invention are described in detail, but the present invention is not limited to described reality Execute mode.For those of ordinary skill in the art, in the range of the principle and technological thought of the present invention, these are implemented Mode carries out multiple change, revises, replaces and deformation still falls within protection scope of the present invention.

Claims (4)

1. bolt interface performance recognition methods under different pre-fastening moments, it is characterised in that comprise the following steps:

Step 1, sets up the FEM (finite element) model of connected piece, described bolt bridging arrangement according to the geometric model of bolt bridging arrangement Including overlapped part and bolt connection piece, described overlapped part includes upper and lower lapping plate；

Step 2, utilizes Orthotropic Thin layer unit to be modeled the interface between connected piece, and described thin layer element models It is a kind of equivalent description method of interface performance, because the outer performance of dough-making powder is inconsistent in the face of bolt fastening structure joint face, uses Orthotropic material constitutive relation, obtains the Analysis Mode frequency of bolt bridging arrangement analyze model at this on the basis of Rate；

Step 3, carries out modal test to the attachment structure under different pre-fastening moments, it is thus achieved that the mode frequency under different pre-fastening moments Rate；

Step 4, utilizes structure optimization technology, uses the model frequency under different pre-fastening moment, the elastic parameter to thin layer element It is identified, thus the bolt fastening structure interface performance obtained under different pre-fastening moment describes.

Bolt interface performance recognition methods under different pre-fastening moment the most according to claim 1, it is characterised in that described step The modeling of rapid 2 comprises the following steps:

2.1) pre-fastening moment region is determined: according to bolted characteristic, bolt hole local stiffness should be greater than away from bolt hole attached The rigidity near region, the local strengthening region of pre-fastening moment effect is square area, length of side a=2D of square area；

2.2) determine thin layer element material parameter: described orthogonal respectively have 9 independent material parameters to material, be 3 respectively Young's modulus E in individual direction₁₁, E₂₂, E₃₃, Poisson's ratio v₁₂, v₂₃, v₃₁With 3 shear modulus G₁₂, G₂₃, G₃₁；Root thin layer element Basic assumption plane internal strain tends to 0, i.e. ε_x=ε_y=ε_xy≈ 0, then according to the basic theories of orthogonal anisotropy thin layer element Material constitutive equation after can being degenerated is

$\left\{\begin{array}{c}{\mathrm{\σ}}_{zz}\\ {\mathrm{\τ}}_{yz}\\ {\mathrm{\τ}}_{zx}\end{array}\right\}=\left[\begin{array}{ccc}{E}_{33}& 0& 0\\ 0& G_{23}& 0\\ 0& 0& G_{31}\end{array}\right]\left\{\begin{array}{c}{\mathrm{\ϵ}}_{zz}\\ {\mathrm{\γ}}_{yz}\\ {\mathrm{\γ}}_{zx}\end{array}\right\}---\left(1\right)$

Each parameter σ in formula (1)_zz, τ_yz, τ_zx, ε_zz, γ_yz, γ_zxRepresent z yz direction and zx direction outside direct stress, face respectively Shearing stress, z is yz direction and the shearing strain of zx direction outside normal strain, face；E₃₃, G₂₃And G₃₁It is respectively z yz direction and zx outside, face Direction elastic parameter；Have only to given E₃₃, G₂₃And G₃₁Initial value, it is possible to realize thin layer element mechanical property characterize；

2.3) thin layer element thickness is determined: determined the thickness of thin layer element by definition proportionality coefficient r:

$r=\frac{max(l_1,l_2)}{d}---\left(2\right)$

L in formula (2)₁, l₂Represent the length of thin layer element, width and thickness respectively with d, the value of r is usually 50；

2.4) to the bolt lapping plate utilizing solid element to set up and the bolt utilizing Orthotropic Thin layer unit to be set up The FEM (finite element) model at overlap joint interface carries out model analysis, obtains Analysis Mode frequency.

Bolt interface performance recognition methods under different pre-fastening moment the most according to claim 2, it is characterised in that described step Rapid 3 comprise the following steps:

3.1) utilize the hammering method in modal test, structure is carried out dynamic test, on axis, defines hammer point in the structure, with And at the hammer point of first, border, define a pick-up point；

3.2) with rubber rope, bolt lapping plate is hung, make free boundary structure；With glue, vibration pickup is cohered in institute The pick-up point position, border of choosing；

3.3) with wire, pulse hammer and vibration pickup are accessed the corresponding interface of signal sampler；

3.4) utilize the model analysis module of pilot system, model analysis parameter is set；

3.5) structurally each impacting point edge is applied node impulsive force from direction, face by pulse hammer, gather each measuring point and receiving To input during pulse excitation and output signal；

3.6) with the signal analyzer of pilot system, input/output signal is done fast Fourier transform, obtain the frequency response letter of system Number, then obtains the model frequency of system by curve matching.

Bolt interface performance recognition methods under different pre-fastening moment the most according to claim 3, it is characterised in that described step Rapid 4 comprise the following steps:

4.1) parameter to be optimized is determined: to the Orthotropic Thin layer unit mould describing bolt overlap joint interface performance set up Type, according to step 2.1) obtained by three elastic parameters E₃₃, G₂₃And G₃₁As parameter to be optimized；

4.2) objective optimization function is determined: the Modal Test frequency to the bolt bridging arrangement under obtained different pre-fastening moments Rate, the test value obtained according to step 3, for the Modal Test frequency under each pre-fastening moment, the objective optimization being defined below Function:

$\left\{\begin{array}{c}MinJ\left(p\right)={|{\mathrm{freq}}^e-{\mathrm{freq}}^a\left(p\right)|}_2^2\\ s.t.p_1\≤p\≤p_2\end{array}\right.---\left(3\right)$

Freq in formula (3)^eAnd freq^aRespectively represent Modal Test frequency and Analysis Mode frequency composition vector, p represent treat excellent Changing parameter vector, the physical meaning of this object function is: at the excursion [p of parameter₁p₂In], find the most optimized parameter and make Modal Test frequency and 2 Norm minimums of Analysis Mode frequency vector difference；

4.3) parameters optimization scope is determined: according to experimental rules and mechanics basic relational expression, obtain the change model of parameter to be optimized Enclose [p₁p₂]；

4.4) utilize iteration optimization algorithms, to step 4.2) obtained by object function be optimized, finally try to achieve optimized parameter, Thus obtain describing the elastic parameter value of the Orthotropic Thin layer unit of the bolt interface performance under each pre-fastening moment, from And obtain the mechanics parameter of bolt interface performance.