Self-piercing riveting parameter identification method, identification device, identification system and storage medium

Abstract

The invention discloses a self-piercing riveting parameter identification method, an identification device, an identification system and a computer readable storage medium. The self-piercing riveting parameter identification method comprises the following steps: designing tensile samples at a first angle and a second angle, and respectively carrying out tensile tests; obtaining a first tensile force displacement curve corresponding to the first angle and a second tensile force displacement curve corresponding to the second angle through a tensile test; establishing a self-piercing riveting simplified model based on the self-piercing riveting constraint model; determining a first contrast drawing force displacement curve corresponding to the first angle and a second contrast drawing force displacement curve corresponding to the second angle based on the self-piercing riveting simplified model; and determining a first to-be-identified parameter of the self-piercing riveting constraint model according to the first drawing force displacement curve, the second drawing force displacement curve, the first comparison drawing force displacement curve and the second comparison drawing force displacement curve. In this way, the calculation amount of the parameter identification process is greatly reduced, and the efficiency and precision of parameter identification are effectively improved.

Description

Technical Field

[0001] The present application relates to the field of riveting technology, and in particular to a self-piercing riveting parameter identification method, an identification device, an identification system and a computer-readable storage medium. Background Art

[0002] In recent years, in order to improve the lightweight level of new energy vehicles, a variety of emerging materials have been widely used in body structures. The properties of different materials vary greatly. With the increase in the types of materials, new challenges have been raised for the connection of multi-material hybrid bodies. Self-piercing riveting (SPR) has many advantages such as high strength, no thermal deformation, and automation, and is widely used in the connection of dissimilar materials. Self-piercing riveting still has the possibility of failure in collision conditions, so it is necessary to establish a set of efficient and high-precision self-piercing riveting calculation models. The CONSTRAINED_SPR2 constraint model has high accuracy in simulating the tensile and fracture failure behaviors of self-piercing rivets. However, the CONSTRAINED_SPR2 constraint model includes multiple parameters to be identified, and the current identification accuracy of the parameters to be identified is not high. Summary of the invention

[0003] The embodiments of the present application provide a self-piercing riveting parameter identification method, an identification device, an identification system and a computer-readable storage medium to solve at least one of the above-mentioned technical problems.

[0004] The self-piercing riveting parameter identification method of the embodiment of the present application includes:

[0005] Designing tensile specimens with a first angle and a second angle, and performing tensile tests respectively, wherein the second angle is smaller than the first angle;

[0006] Acquire a first tensile force-displacement curve corresponding to the first angle and a second tensile force-displacement curve corresponding to the second angle through a tensile test;

[0007] A simplified model of self-piercing riveting is established based on the constraint model of self-piercing riveting;

[0008] Determine, based on the simplified self-piercing riveting model, a first comparative tensile force-displacement curve corresponding to the first angle and a second comparative tensile force-displacement curve corresponding to the second angle;

[0009] A first parameter to be identified of the self-piercing riveting constraint model is determined according to the first tensile force-displacement curve, the second tensile force-displacement curve, the first comparative tensile force-displacement curve, and the second comparative tensile force-displacement curve.

[0010] In some embodiments, the first angle is 90 degrees and the second angle is 0 degrees.

[0011] In some embodiments, establishing a simplified self-piercing riveting model based on the self-piercing riveting constraint model includes:

[0012] A simplified model of self-piercing riveting is established based on the self-piercing riveting constraint model and rigid connection unit.

[0013] In some embodiments, the first parameter to be identified includes any one or more of a rivet tensile failure displacement, a rivet shear failure displacement, a displacement ratio corresponding to a rivet maximum tensile force, and a displacement ratio corresponding to a rivet maximum shear force.

[0014] In some embodiments, the first parameter to be identified includes the rivet tensile failure displacement and / or the displacement ratio corresponding to the maximum tensile force of the rivet, and the first parameter to be identified of the self-piercing riveting constraint model is determined according to the first tensile force displacement curve, the second tensile force displacement curve, the first comparative tensile force displacement curve, and the second comparative tensile force displacement curve, including:

[0015] Determining a second parameter to be identified of the self-piercing riveting constraint model according to the first tensile force-displacement curve;

[0016] Determine a first displacement and a second displacement corresponding to the first angle according to the second parameter to be identified and the first comparative tensile force-displacement curve, wherein the first displacement is the displacement of the master and slave plates when the rivet joint force reaches a maximum tensile force, and the second displacement is the displacement of the master and slave plates when the rivet joint force decays from the maximum tensile force to zero;

[0017] The first parameter to be identified is determined according to the first displacement and the second displacement.

[0018] In some embodiments, the first parameter to be identified includes the rivet shear failure displacement and / or the displacement ratio corresponding to the maximum shear force of the rivet, and the first parameter to be identified of the self-piercing riveting constraint model is determined according to the first tensile force displacement curve, the second tensile force displacement curve, the first comparative tensile force displacement curve, and the second comparative tensile force displacement curve, including:

[0019] Determining a third parameter to be identified of the self-piercing riveting constraint model according to the second tensile force-displacement curve;

[0020] Determine a third displacement and a fourth displacement corresponding to the second angle according to the third parameter to be identified and the second comparative tensile force-displacement curve, wherein the third displacement is the displacement of the master and slave plates when the rivet joint force reaches the maximum shear force, and the fourth displacement is the displacement of the master and slave plates when the rivet joint force decays from the maximum shear force to zero;

[0021] The first parameter to be identified is determined according to the third displacement and the fourth displacement.

[0022] In some embodiments, the self-piercing riveting parameter identification method further includes:

[0023] Determining a second parameter to be identified of the self-piercing riveting constraint model according to the first tensile force-displacement curve;

[0024] A third parameter to be identified of the self-piercing riveting constraint model is determined according to the second tensile force-displacement curve.

[0025] In some embodiments, the second parameter to be identified includes the maximum tensile force of the rivet, and the third parameter to be identified includes the maximum shear force of the rivet.

[0026] In some embodiments, the self-piercing riveting parameter identification method further includes:

[0027] Designing tensile specimens with a third angle and a fourth angle, and performing tensile tests respectively, wherein the third angle is smaller than the first angle and larger than the second angle, and the fourth angle is smaller than the third angle and larger than the second angle;

[0028] Acquire, by tensile testing, a third tensile force-displacement curve corresponding to the third angle and a fourth tensile force-displacement curve corresponding to the fourth angle;

[0029] Establishing a simulation optimization iterative model based on the third tensile force-displacement curve and the fourth tensile force-displacement curve;

[0030] A fourth parameter to be identified of the self-piercing riveting constraint model is determined based on the simulation optimization iterative model.

[0031] In some embodiments, the third angle is 60 degrees and the fourth angle is 30 degrees.

[0032] In some embodiments, the fourth parameter to be identified includes at least one displacement scaling factor.

[0033] In some embodiments, determining a fourth parameter to be identified of the self-piercing riveting constraint model based on the simulation optimization iterative model includes:

[0034] Initializing the fourth parameter to be identified;

[0035] Performing a DOE test design on the fourth parameter to be identified, and determining a parameter sample set corresponding to the fourth parameter to be identified in a sample space;

[0036] Performing finite element analysis on the parameter sample set based on the first parameter to be identified, the second parameter to be identified, and the third parameter to be identified to determine a third comparative tensile force-displacement curve corresponding to the third angle and a fourth comparative tensile force-displacement curve corresponding to the fourth angle;

[0037] Calculating a curve difference by a dynamic time warping method according to the third tensile force-displacement curve, the fourth tensile force-displacement curve, the third comparative tensile force-displacement curve, and the fourth comparative tensile force-displacement curve;

[0038] Constructing a radial basis neural network response surface model according to the parameter sample set and the curve difference;

[0039] The fourth parameter to be identified is determined based on the radial basis neural network response surface model, and the fourth parameter to be identified is optimized based on an optimization algorithm.

[0040] In some embodiments, the determining the fourth parameter to be identified of the self-piercing riveting constraint model based on the simulation optimization iterative model further includes:

[0041] When the curve difference is less than a first threshold value and / or the change value of the fourth parameter to be identified is less than a second threshold value, outputting the optimized fourth parameter to be identified;

[0042] When the curve difference is greater than the first threshold and / or the change value of the fourth parameter to be identified is greater than the second threshold, the sample space is reduced based on the sequential response surface method, and the step of performing DOE experimental design on the fourth parameter to be identified and determining the parameter sample set corresponding to the fourth parameter to be identified in the sample space is returned.

[0043] The self-piercing riveting parameter identification device of the embodiment of the present application includes:

[0044] A design module, used for designing tensile specimens with a first angle and a second angle, and performing tensile tests respectively, wherein the second angle is smaller than the first angle;

[0045] an acquisition module, configured to acquire, through a tensile test, a first tensile force-displacement curve corresponding to the first angle and a second tensile force-displacement curve corresponding to the second angle;

[0046] Establishing a module for establishing a simplified self-piercing riveting model based on a self-piercing riveting constraint model;

[0047] A first determination module is used to determine a first comparative tensile force displacement curve corresponding to the first angle and a second comparative tensile force displacement curve corresponding to the second angle based on the simplified self-piercing riveting model;

[0048] The second determination module is used to determine a first parameter to be identified of the self-piercing riveting constraint model according to the first tensile force displacement curve, the second tensile force displacement curve, the first comparative tensile force displacement curve, and the second comparative tensile force displacement curve.

[0049] The self-piercing riveting parameter identification system of the embodiment of the present application comprises one or more processors and a memory, wherein the memory stores a computer program, and when the computer program is executed by the processor, the self-piercing riveting parameter identification method of any of the above embodiments is implemented.

[0050] The computer-readable storage medium of the embodiment of the present application stores a computer program thereon, and when the program is executed by a processor, the self-piercing riveting parameter identification method of any of the above embodiments is implemented.

[0051] In the self-piercing riveting parameter identification method, identification device, identification system and computer-readable storage medium of the embodiment of the present application, a simplified self-piercing riveting model is established based on the self-piercing riveting constraint model, and the first tensile force displacement curve corresponding to the first angle of the tensile specimen, the second tensile force displacement curve corresponding to the second angle, and the first comparative tensile force displacement curve corresponding to the first angle of the simplified self-piercing riveting model, and the second comparative tensile force displacement curve corresponding to the second angle are calculated to determine the first parameter to be identified, thereby eliminating the complex iterative process. In this way, the amount of calculation in the parameter identification process is greatly reduced, and the efficiency and accuracy of parameter identification are effectively improved.

[0052] Additional aspects and advantages of the embodiments of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through the practice of the embodiments of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0054] Figure 1 is a flow chart of a method for identifying parameters of self-piercing riveting in certain embodiments of the present application;

[0055] Figure 2 is a flow chart of a method for identifying parameters of self-piercing riveting in certain embodiments of the present application;

[0056] Figure 3 is a schematic diagram of the structure of a tensile specimen in certain embodiments of the present application;

[0057] Figure 4 It is a schematic diagram of the structure of tensile specimens at different angles in certain embodiments of the present application;

[0058] Figure 5 is a schematic diagram of a first tensile force-displacement curve corresponding to a first angle and a second tensile force-displacement curve corresponding to a second angle in certain embodiments of the present application;

[0059] Figure 6 It is a structural schematic diagram of a simplified model of self-piercing riveting in certain embodiments of the present application;

[0060] Figure 7 is a schematic diagram of a tensile force displacement curve under a rivet tensile condition corresponding to a self-piercing riveting constraint model in certain embodiments of the present application;

[0061] Figure 8 is a flow chart of a method for identifying parameters of self-piercing riveting in certain embodiments of the present application;

[0062] Fig. 9 is a flow chart of a method for identifying parameters of self-piercing riveting in certain embodiments of the present application;

[0063] Fig.10 is a flow chart of a method for identifying parameters of self-piercing riveting in certain embodiments of the present application;

[0064] Fig.11 is a flow chart of a method for identifying parameters of self-piercing riveting in certain embodiments of the present application;

[0065] Fig.12 is a schematic diagram of a curve of force and displacement of a rivet joint of a tensile specimen at a first angle in certain embodiments of the present application;

[0066] Fig.13 is a schematic diagram of load variation over time of a tensile specimen at a first angle in certain embodiments of the present application;

[0067] Fig.14 It is a schematic diagram of tensile force-displacement curves of a simplified main plate and a simplified slave plate of a simplified self-piercing riveting model in certain embodiments of the present application during a load loading process;

[0068] Fig.15 is a schematic diagram of the comparison results of the first tensile force-displacement curve and the first simulated tensile force-displacement curve in certain embodiments of the present application;

[0069] Fig.16 is a schematic diagram of the comparison results of the second tensile force-displacement curve and the second simulated tensile force-displacement curve in certain embodiments of the present application;

[0070] Fig.17 is a flow chart of a method for identifying parameters of self-piercing riveting in certain embodiments of the present application;

[0071] Fig.18is a flow chart of a method for identifying parameters of self-piercing riveting in certain embodiments of the present application;

[0072] Fig.19 is a flow chart of a method for identifying parameters of self-piercing riveting in certain embodiments of the present application;

[0073] Fig. 20 is a schematic diagram of the convergence process of the displacement scaling coefficient ALPHA1 in certain embodiments of the present application;

[0074] Fig.21 is a schematic diagram of the convergence process of the displacement scaling coefficient ALPHA2 in certain embodiments of the present application;

[0075] Fig. 22 is a schematic diagram of the convergence process of the displacement scaling coefficient ALPHA3 in certain embodiments of the present application;

[0076] Fig.23 is a schematic diagram of the comparison results of the third tensile force-displacement curve and the third simulated tensile force-displacement curve in certain embodiments of the present application;

[0077] Fig.24 is a schematic diagram of a comparison result between a fourth tensile force-displacement curve and a fourth simulated tensile force-displacement curve in certain embodiments of the present application;

[0078] Fig.25 is a schematic diagram of a module of a self-piercing riveting parameter identification device according to certain embodiments of the present application;

[0079] Fig.26 is a schematic diagram of a module of a self-piercing riveting parameter identification system in certain embodiments of the present application;

[0080] Fig. 27 It is a schematic diagram of the connection status between a computer-readable storage medium and a processor in certain embodiments of the present application. DETAILED DESCRIPTION

[0081] The following is a further description of the embodiments of the present application in conjunction with the accompanying drawings. The same or similar reference numerals in the accompanying drawings represent the same or similar elements or elements with the same or similar functions from beginning to end. In addition, the embodiments of the present application described below in conjunction with the accompanying drawings are exemplary and are only used to explain the embodiments of the present application, and cannot be understood as limiting the present application.

[0082] In recent years, in order to improve the lightweight level of new energy vehicles, emerging materials such as ultra-high-strength steel, aluminum alloy, magnesium alloy, carbon fiber and engineering plastics have been widely used in body structures, changing the traditional body materials mainly based on steel. With the increase in the types of materials, the properties of different materials vary greatly, which poses new challenges to the connection of multi-material hybrid bodies. Self-piercing riveting (SPR) is a mechanical cold connection with many advantages such as high strength, no thermal deformation, environmentally friendly connection process, low cost, and automation, and is widely used in the connection of dissimilar materials.

[0083] Like resistance spot welding, self-piercing riveting may still fail in collision conditions, so it is necessary to establish an efficient and high-precision self-piercing riveting calculation model. A detailed self-piercing riveting numerical simulation model consumes a lot of modeling time and computing resources and is not suitable for large-scale simulation calculations.

[0084] In related technologies, by observing and testing the mechanical characteristics and failure forms of self-piercing rivets under different working conditions, a complete load-displacement change relationship from the initial deformation to the failure process was established, and a CONSTRAINED_SPR2 constraint model was developed based on the LS-DYNA program. Studies have shown that this model has high accuracy in simulating the tensile and fracture failure behaviors of self-piercing rivets.

[0085] The parameters to be identified in the CONSTRAINED_SPR2 constraint model include: maximum tensile force FN, maximum shear force FT, rivet tensile failure displacement DN, rivet shear failure displacement DT, displacement ratio XIN corresponding to the maximum tensile force of the rivet, displacement ratio XIT corresponding to the maximum shear force of the rivet, and displacement scaling coefficients ALPHA1, ALPHA2, and ALPHA3. Among them, except for the maximum tensile force FN and the maximum shear force FT, which can be directly obtained through experiments, the remaining seven parameters, namely, rivet tensile failure displacement DN, rivet shear failure displacement DT, displacement ratio XIN corresponding to the maximum tensile force of the rivet, displacement ratio XIT corresponding to the maximum shear force of the rivet, and displacement scaling coefficients ALPHA1, ALPHA2, and ALPHA3, all need to be identified.

[0086] In the related technology, simulation and test data are directly used to identify related parameters using a cyclic iteration method. This method requires many parameters to be identified, takes a long time, and is prone to local convergence and cannot obtain a global optimal solution. The convergence value of each parameter may be affected by the initial value of the iteration.

[0087] In other related technologies, the initial value of the parameter to be identified is set as: ξ n =0.5,ξ t =0.5. Among them, is the tensile failure displacement of the rivet; h is the rivet shear failure displacement; m h is the thickness of the motherboard; s is the plate thickness; n is the displacement ratio corresponding to the maximum tensile force of the rivet; t The displacement ratio XIT corresponding to the maximum shear force of the rivet. A fine simulation model of rivet failure is established, and the fine simulation curves of displacement and force are obtained by adjusting the first parameter; a simplified rivet failure model is established based on the first parameter obtained by the fine simulation model of rivet failure, and the simplified simulation curves of displacement and force are obtained by adjusting the second parameter. This method requires the establishment of a fine simulation model and is not efficient.

[0088] Therefore, please refer to Figure 1 and Figure 2 The present application provides a method for identifying parameters of a self-piercing riveting joint, comprising:

[0089] 010: Designing a tensile test specimen 100 with a first angle and a second angle, and performing tensile tests respectively, wherein the second angle is smaller than the first angle;

[0090] 020: obtaining a first tensile force-displacement curve corresponding to the first angle and a second tensile force-displacement curve corresponding to the second angle through a tensile test;

[0091] 030: Establish a simplified model of self-piercing riveting based on the self-piercing riveting constraint model 200;

[0092] 040: Determine a first comparative tensile force displacement curve corresponding to the first angle and a second comparative tensile force displacement curve corresponding to the second angle based on the simplified self-piercing riveting model 200;

[0093] 050: Determine a first parameter to be identified of the self-piercing riveting constraint model according to the first tensile force displacement curve, the second tensile force displacement curve, the first comparative tensile force displacement curve, and the second comparative tensile force displacement curve.

[0094] In the self-piercing riveting parameter identification method of the embodiment of the present application, a self-piercing riveting simplified model 200 is established based on the self-piercing riveting constraint model, and the first tensile force displacement curve corresponding to the first angle of the tensile specimen 100, the second tensile force displacement curve corresponding to the second angle, and the first comparative tensile force displacement curve corresponding to the first angle of the self-piercing riveting simplified model 200, and the second comparative tensile force displacement curve corresponding to the second angle are calculated and determined to determine the first parameter to be identified, thereby eliminating the complex iterative process. In this way, the amount of calculation in the parameter identification process is greatly reduced, and the efficiency and accuracy of parameter identification are effectively improved.

[0095] Specifically, the tensile specimen 100 may be a KS-2 type tensile specimen 100, such as Figure 3As shown, the KS-2 type tensile specimen 100 is a standard specimen for riveting parameter identification, and the tensile specimen 100 includes a rivet, a main plate 10, and a sub-plate 20. The parameters to be identified for self-piercing riveting include a first parameter to be identified, and the first parameter to be identified includes parameters under tensile conditions and / or shear conditions. It should be noted that when tensile forces in the same direction are applied to tensile specimens 100 at different angles, the tensile specimens 100 at different angles may be in different conditions. Therefore, tensile specimens 100 at different angles (such as Figure 4 to identify the parameters under different working conditions.

[0096] A tensile specimen 100 with a first angle and a second angle is designed, wherein the second angle is smaller than the first angle. A tensile test is performed on the tensile specimen 100 with the first angle to obtain a first tensile force-displacement curve corresponding to the first angle; a tensile test is performed on the tensile specimen 100 with the second angle to obtain a second tensile force-displacement curve corresponding to the second angle. In one example, when tensile forces are applied to the tensile specimens 100 with the first angle and the second angle in a vertical direction, respectively, the tensile specimen 100 with the first angle is in a tensile condition, and the tensile specimen 100 with the second angle is in a shear condition. The first tensile force-displacement curve and the second tensile force-displacement curve are as shown in FIG. Figure 5 shown.

[0097] Afterwards, a simplified self-piercing riveting model 200 (such as Figure 6 As shown in Figure 2, the self-piercing riveting constraint model is a connection model developed based on the riveting tensile test data. It describes the relationship between the force and displacement of the riveted joint and includes the riveting fracture failure criterion. Figure 7 The tensile force displacement curve under the rivet tensile condition corresponding to the self-piercing riveting constraint model is shown, which can be described by the following formula:

[0098]

[0099] in, is the normalized tensile load, that is is the maximum tensile load. is the joint damage η max The function of η max The range is 0-1 and can be expressed as δ n is the normal displacement of the rivet under tensile conditions, which is a variable; is the normal displacement of the rivet when it fails under tension. ξ n is the damage corresponding to the maximum tensile load, which can be expressed as is the normal displacement of the rivet corresponding to the maximum tensile load. ξ n It is the first parameter to be identified under the tensile condition.

[0100] When η max ≤ξ n , that is, when the joint damage is less than or equal to the damage corresponding to the maximum tensile load, the joint load evolves in a power exponential form. The power exponent parameter is EXPN, which is generally 8. The evolution form is similar to the elastic-plastic deformation of the material. When η max > n When the joint damage η max When the damage is greater than the maximum tensile load, the joint load degenerates linearly until η max =1, the joint is completely damaged and the riveting fails. It is also between 0 and 1. Of course, the joint damage can also evolve in an exponential or other form.

[0101] Similarly, when the riveted joint is subjected to shear force, it can be described by the following formula:

[0102]

[0103] in, is the normalized shear load, that is f t max is the maximum shear load. is the joint damage η max The function of η max The range is 0-1 and can be expressed as δ t is the normal displacement of the rivet under shear conditions, which is a variable; is the normal displacement when the rivet fails under shear conditions. ξ t is the damage corresponding to the maximum shear load, which can be expressed as in is the normal displacement of the rivet corresponding to the maximum shear load. ξ t It is the first parameter to be identified under the shear condition.

[0104] The evolution process of joint damage in riveted joints under shear load is consistent with that under tensile load. max ≤ξ t , that is, when the joint damage is less than or equal to the damage corresponding to the maximum shear load, the joint load evolves in a power exponential form. The power exponent parameter is EXPN. When η max > t When the joint damage η max When the damage is greater than the maximum shear load, the joint load degenerates linearly until η max=1, the joint is completely damaged and the riveting fails. It is also between 0 and 1. Of course, the joint damage can also evolve in an exponential or other form.

[0105] After establishing the simplified self-piercing riveting model 200 corresponding to the tensile specimen 100, the first comparative tensile force-displacement curve corresponding to the first angle and the second comparative tensile force-displacement curve corresponding to the second angle can be determined based on the simplified self-piercing riveting model 200, and then the first parameter to be identified of the self-piercing riveting constraint model can be determined according to the first tensile force-displacement curve, the second tensile force-displacement curve, the first comparative tensile force-displacement curve, and the second comparative tensile force-displacement curve.

[0106] In the related art, the first parameter to be identified is identified by an iterative method, which has a large amount of calculation, low identification efficiency, and low identification accuracy. In the implementation of the present application, a simplified self-piercing riveting model 200 is established based on the self-piercing riveting constraint model, and the first tensile force displacement curve corresponding to the first angle of the tensile specimen 100, the second tensile force displacement curve corresponding to the second angle, and the first tensile force displacement curve corresponding to the first angle of the simplified self-piercing riveting model 200. The first parameter to be identified is directly determined by calculation, eliminating the complex iterative process, thus greatly reducing the amount of calculation in the parameter identification process and effectively improving the efficiency and accuracy of parameter identification.

[0107] In some embodiments, the first angle is 90 degrees and the second angle is 0 degrees. Figure 3 As shown in (a) ks-2-90, the second angle tensile specimen 100 is as shown in Figure 3 When the tensile force is applied to the tensile specimens 100 at the first angle and the second angle in the vertical direction, the tensile specimens 100 at the first angle are in a tensile state, and the tensile specimens 100 at the second angle are in a shear state.

[0108] In some embodiments, the first parameter to be identified includes any one or more of a rivet tensile failure displacement, a rivet shear failure displacement, a displacement ratio corresponding to a rivet maximum tensile force, and a displacement ratio corresponding to a rivet maximum shear force.

[0109] Specifically, the rivet tensile failure displacement DN is the The rivet shear failure displacement DT is also the The displacement ratio corresponding to the maximum tensile force of the rivet is ξ in the above embodiment. n ; The displacement ratio corresponding to the maximum shear force of the rivet is ξ in the aforementioned embodiment t .

[0110] The first parameter to be identified may include only the rivet tensile failure displacement, or only the rivet shear failure displacement, or only the displacement ratio corresponding to the maximum tensile force of the rivet, or only the displacement ratio corresponding to the maximum shear force of the rivet. It may also include any two, three or four of the rivet tensile failure displacement, the rivet shear failure displacement, the displacement ratio corresponding to the maximum tensile force of the rivet, and the displacement ratio corresponding to the maximum shear force of the rivet.

[0111] See also Figure 5 and Figure 8 In some embodiments, a simplified self-piercing riveting model 200 (ie, 030) is established based on the self-piercing riveting constraint model, including:

[0112] 031: A simplified self-piercing riveting model 200 is established based on the self-piercing riveting constraint model and the rigid connection unit 240.

[0113] Specifically, in the self-piercing riveting constraint model, the failure of the self-piercing riveting is based on the macroscopic displacement, and its parameters are not sensitive to the mesh size. Therefore, when establishing the simplified self-piercing riveting model 200, the mesh size is not restricted. Within the influence range of the simplified rivet 230, a rigid connection unit 240 is added. The rigid connection unit 240 has a high strength, so that only the simplified main plate 210 and the simplified secondary plate 220 at the connection of the simplified rivet 230 are allowed to deform, thereby limiting the displacement of the simplified rivet 230.

[0114] See also Figure 2 and Fig. 9 In some embodiments, the self-piercing riveting parameter identification method further includes:

[0115] 060: Determine a second parameter to be identified of the self-piercing riveting constraint model according to the first tensile force-displacement curve;

[0116] 070: Determine the third parameter to be identified of the self-piercing riveting constraint model according to the second tensile force-displacement curve.

[0117] Specifically, the parameters to be identified for self-piercing riveting also include a second parameter to be identified and a third parameter to be identified. In some embodiments, the second parameter to be identified includes the maximum tensile force FN of the rivet, and the third parameter to be identified includes the maximum shear force FT of the rivet. Figure 5 As shown, the highest point of the first tensile force displacement curve is the maximum tensile force FN of the rivet, and the highest point of the second tensile force displacement curve is the maximum shear force FT of the rivet.

[0118] It should be noted that the maximum tensile force FN of the rivet corresponds to The maximum shear force FT of the rivet corresponds to f in the above embodiment. t max .

[0119] See also Figure 2 and Fig.10 In some embodiments, the first parameter to be identified includes the rivet tensile failure displacement and / or the displacement ratio corresponding to the maximum tensile force of the rivet. The first parameter to be identified (i.e., 050) of the self-piercing riveting constraint model is determined according to the first tensile force displacement curve, the second tensile force displacement curve, the first comparative tensile force displacement curve, and the second comparative tensile force displacement curve, including:

[0120] 051: Determine a second parameter to be identified of the self-piercing riveting constraint model according to the first tensile force-displacement curve;

[0121] 052: Determine a first displacement and a second displacement corresponding to the first angle according to a second parameter to be identified and a first comparative tensile force displacement curve, wherein the first displacement is the displacement of the master and slave plates when the rivet joint force reaches a maximum tensile force, and the second displacement is the displacement of the master and slave plates when the rivet joint force decays from the maximum tensile force to zero;

[0122] 053: Determine a first parameter to be identified according to the first displacement and the second displacement.

[0123] See also Figure 2 and Fig.11 In some embodiments, the first parameter to be identified includes the rivet shear failure displacement and / or the displacement ratio corresponding to the maximum shear force of the rivet. The first parameter to be identified (i.e., 050) of the self-piercing riveting constraint model is determined according to the first tensile force displacement curve, the second tensile force displacement curve, the first comparative tensile force displacement curve, and the second comparative tensile force displacement curve, including:

[0124] 054: Determine the third parameter to be identified of the self-piercing riveting constraint model according to the second tensile force-displacement curve;

[0125] 055: Determine a third displacement and a fourth displacement corresponding to the second angle according to the third parameter to be identified and the second comparative tensile force displacement curve, wherein the third displacement is the displacement of the master and slave plates when the rivet joint force reaches the maximum shear force, and the fourth displacement is the displacement of the master and slave plates when the rivet joint force decays from the maximum shear force to zero;

[0126] 056: Determine a first parameter to be identified according to the third displacement and the fourth displacement.

[0127] Taking the tensile condition (corresponding to the first angle) as an example, the normalized tensile load The expression is rewritten into the following real load:

[0128]

[0129] It should be noted that the overall displacement of the tensile specimen 100 is the total displacement formed by the superposition of the rivet displacement and the master and slave plate displacements, and the master and slave plate displacements are the displacements of the main plate 10 and the slave plate 20. The rivet displacement is expressed as follows:

[0130] δ n =δ total -δ hm

[0131]

[0132] Among them, δ total is the overall displacement of the clamping end of the tensile specimen 100. hm Substituting the displacement of the master and slave plates into the true load expression, we can get:

[0133]

[0134] When δ n =δ total =δ hm = 0, f n (δ total )=0; when hour, f n (δ total ) reaches its maximum value; when hour, f n (δ total ) decreases to zero. Known, if you want to identify Just identify That's it; because Known, if you want to identify Just identify That's it. The maximum tensile force for the rivet joint (i.e., the second parameter to be identified FN) when the master and slave plates are displaced; The force of the rivet joint is from the maximum tensile force The displacement of the master and slave plates when they decay to zero.

[0135] The following describes in detail The specific process of identification is as follows: First, based on the simplified model of self-piercing riveting, 200 pairs of The self-piercing riveting simplified model 200 is established, and the second parameter to be identified FN and the third parameter to be identified FT are input. The normal displacement of the rivet when it fails under the tensile condition Normal displacement at rivet failure under shear conditions You can also enter the value based on the result of the tensile test, or enter a value slightly larger than the tensile test result. The damage ξ corresponding to the maximum tensile loadn and the damage ξ corresponding to the maximum shear load t The input value of is in the range of 0.8-1.0, so that when the rivet joint force reaches the maximum force, the self-pierce riveting simplified model 200 does not participate in the riveting coupling contribution.

[0136] The simplified self-piercing riveting model 200 includes a simplified rivet 230, a simplified main plate 210, and a simplified secondary plate 220. A velocity load is applied to the simplified main plate 210, and a fixed constraint is applied to the simplified secondary plate 220. A first comparative tensile force displacement curve corresponding to a first angle under the velocity load is determined. The first comparative tensile force displacement curve is as follows: Fig.12 As shown, when the rivet joint force reaches the maximum tensile force (that is, the second parameter to be identified FN), the corresponding displacement is the displacement of the master and slave plates That is, the first displacement. It should be noted that in the simplified self-piercing riveting model 200, the master-slave plate displacement refers to the displacement of the simplified main plate 210 and the simplified slave plate 220. It can be calculated In the simplified model 200 of self-piercing riveting, the overall displacement δ of the clamping end total correspond Figure 6 The displacement of the line from A to B in .

[0137] right The identification can refer to According to the idea of Fig.13 The simplified self-piercing riveting model 200 is force loaded in a manner to determine a first comparative tensile force displacement curve corresponding to the first angle under the force load, such as Fig.14 As shown. Among them, T max In order to apply velocity load on the simplified main plate 210, the rivet joint force reaches the maximum tensile force during the process of applying fixed constraints on the simplified slave plate 220. (that is, the third parameter to be identified FT), T final The maximum tensile force The moment when it decays to zero. final Set according to the actual situation. The setting rules can be T final ≥2T max .

[0138] Before the joint reaches the maximum load, the simplified main plate 210 and the simplified secondary plate 220 undergo elastic-plastic deformation, and the displacement gradually increases until the displacement reaches After the positive tensile force of the simplified main plate 210 and the simplified secondary plate 220 is attenuated, the displacement is restored to some extent, and the restored part is the elastic deformation of the simplified main plate 210 and the simplified secondary plate 220. The displacement when it decays to zero is That is the second displacement, and then according to It can be calculated Furthermore, we can calculate ξ n It is the first parameter to be identified under the tensile condition.

[0139] Similarly, under the shear condition (corresponding to the second angle), a second comparative tensile force displacement curve corresponding to the second angle is determined based on the simplified self-piercing riveting model 200, and the second comparative tensile force displacement curve includes a second comparative tensile force displacement curve under velocity load and a second comparative tensile force displacement curve under force load. According to the second comparative tensile force displacement curve under velocity load, when the rivet joint force reaches the maximum shear force f t max (ie, the second parameter to be identified FN), the corresponding displacement is the displacement of the simplified main board 210 and the simplified slave board 220 That is the third displacement. It can be calculated According to the second comparative tensile force displacement curve under velocity load, when the rivet joint force changes from the maximum shear force f t max When the decay reaches zero, the displacement of the simplified main board 210 and the simplified slave board 220 is That is the fourth shift, and then according to It can be calculated Furthermore, we can calculate ξ t It is the first parameter to be identified under the shear condition.

[0140] It should be noted that in shear and tension conditions, the displacement of the master and slave plates is much smaller than the rivet displacement and can be ignored in rough calculations. In some embodiments, the overall displacement of the clamping end can be used to replace the rivet displacement in the estimation.

[0141] Substitute the identified first parameter to be identified into the self-piercing riveting constraint model for simulation, calculate the first simulated tensile force displacement curve corresponding to the first angle and the second simulated tensile force displacement curve corresponding to the second angle, and compare them with the first tensile force displacement curve and the second tensile force displacement curve respectively. The comparison result of the first angle is as follows: Fig.15 As shown in the figure, the alignment result of the second angle is as follows Fig.16 As shown in the figure, it can be seen that the first parameter to be identified by the self-piercing riveting parameter identification method according to the embodiment of the present application has a higher accuracy.

[0142] See also Figure 2 and Fig.17 In some embodiments, the self-piercing riveting parameter identification method further includes:

[0143] 080: designing tensile specimens 100 with a third angle and a fourth angle, and performing tensile tests respectively, the third angle is smaller than the first angle and larger than the second angle, and the fourth angle is smaller than the third angle and larger than the second angle;

[0144] 090: obtaining, through a tensile test, a third tensile force-displacement curve corresponding to the third angle and a fourth tensile force-displacement curve corresponding to the fourth angle;

[0145] 0100: establishing a simulation optimization iteration model based on the third tensile force-displacement curve and the fourth tensile force-displacement curve;

[0146] 0110: Determine the fourth parameter to be identified of the self-piercing riveting constraint model based on the simulation optimization iterative model.

[0147] Specifically, the parameters to be identified of the self-piercing riveting also include a fourth parameter to be identified, and the fourth parameter to be identified can be identified under the tension-shear combination working condition. The tensile test specimen 100 is designed with a third angle and a fourth angle, and the third angle and the fourth angle take values ​​between the first angle and the second angle, the third angle is smaller than the first angle and larger than the second angle, and the fourth angle is smaller than the third angle and larger than the second angle.

[0148] Considering the complexity of the actual load, it is necessary to use the dimensionless parameter α to correct the inclined loading condition. The correction formula is as follows:

[0149]

[0150] in:

[0151]

[0152] In the above formula, θ is the angle between the tensile load and the shear load. In some cases, 0<α 1 <α 2 <1<α 3 α 1 , α 2 , α 3 That is, the fourth parameters to be identified are ALPHA1, ALPHA2, and ALPHA3. A tensile test is performed on the tensile specimen 100 at the third angle to obtain a third tensile force-displacement curve corresponding to the third angle; a tensile test is performed on the tensile specimen 100 at the fourth angle to obtain a fourth tensile force-displacement curve corresponding to the fourth angle. Based on LS-OPT, a simulation optimization iterative model is jointly established according to the third tensile force-displacement curve and the fourth tensile force-displacement curve, and then iterative optimization is performed based on the simulation optimization iterative model to determine the fourth parameter to be identified of the self-piercing riveting constraint model.

[0153] In some embodiments, the third angle is 60 degrees and the fourth angle is 30 degrees. Figure 3 As shown in (b) ks-2-60, the second angle tensile specimen 100 is as shown in Figure 3 As shown in (c) ks-2-30, when the tensile force is applied to the tensile specimens 100 at the third angle and the fourth angle respectively in the vertical direction, the tensile specimens 100 at the third angle and the fourth angle are both in the tensile shear combination working condition.

[0154] In some embodiments, the fourth parameter to be identified includes at least one displacement scaling factor. The fourth parameter to be identified may include 1, 2, 3 or more displacement scaling factors. In one example, the fourth parameter to be identified includes 3 displacement scaling factors, namely ALPHA1, ALPHA2 and ALPHA3.

[0155] In some embodiments, after establishing the simulation optimization iterative model, the first parameter to be identified, the second parameter to be identified, and the third parameter to be identified are brought into the simulation optimization iterative model, and the simulation optimization iterative model is iteratively optimized to determine the fourth parameter to be identified of the self-piercing riveting constraint model.

[0156] See also Figure 2 and Fig.18 In some embodiments, determining the fourth parameter to be identified (i.e., 0110) of the self-piercing riveting constraint model based on the simulation optimization iterative model includes:

[0157] 0111: Initialize the fourth parameter to be identified;

[0158] 0112: Perform DOE test design on the fourth parameter to be identified, and determine a parameter sample set corresponding to the fourth parameter to be identified in the sample space;

[0159] 0113: performing finite element analysis on the parameter sample set based on the first parameter to be identified, the second parameter to be identified, and the third parameter to be identified, and determining a third comparative tensile force-displacement curve corresponding to the third angle and a fourth comparative tensile force-displacement curve corresponding to the fourth angle;

[0160] 0114: Calculating the curve difference by a dynamic time warping method according to the third tensile force displacement curve, the fourth tensile force displacement curve, the third comparative tensile force displacement curve, and the fourth comparative tensile force displacement curve;

[0161] 0115: Construct a radial basis neural network response surface model based on parameter sample sets and curve differences;

[0162] 0116: Determine a fourth parameter to be identified based on a radial basis function neural network response surface model, and optimize the fourth parameter to be identified based on an optimization algorithm.

[0163] Specifically, the fourth parameter to be identified includes three displacement scaling coefficients. The fourth parameter to be identified is initialized. The initial values ​​of the three displacement scaling coefficients ALPHA1, ALPHA2, and ALPHA3 can be set to 0.1, 0.5, and 1.0 respectively, and the constraint condition 0<α is added. 1 <α 2 <1<α 3 .

[0164] After initialization, a DOE experiment design is performed on the fourth parameter to be identified, and a parameter sample set corresponding to the fourth parameter to be identified is determined in the sample space. The sample space is determined according to the above constraints, and the parameter sample set includes multiple groups of fourth parameters to be identified, ensuring that the parameter sample set reasonably covers the entire sample space. The DOE experiment design can be designed using any design method, which is not limited here, for example, using a typical orthogonal experimental design method, a Latin hypercube design method, or a full factorial design method.

[0165] Afterwards, based on the first parameter to be identified, the second parameter to be identified, and the third parameter to be identified, a finite element model can be established according to each group of fourth parameters to be identified in the parameter sample set, and for each finite element model, a third comparative tensile force displacement curve corresponding to the third angle and a fourth tensile force displacement curve corresponding to the fourth angle are calculated respectively. According to the third tensile force displacement curve, the fourth tensile force displacement curve, the third comparative tensile force displacement curve, and the fourth comparative tensile force displacement curve, a curve difference between the third tensile force displacement curve and the third comparative tensile force displacement curve, and a curve difference between the fourth tensile force displacement curve and the fourth comparative tensile force displacement curve are calculated by a dynamic time warping (DTW) method.

[0166] According to the parameter sample set and the curve difference, a radial basis function neural network (RBF) response surface model can be constructed. Among them, the input of the radial basis function neural network response surface model is the fourth parameter to be identified, one of the outputs is the curve difference, and the other output is the rivet failure cutoff time. The rivet failure cutoff time can be set to the time when the rivet joint force drops to 0.1kN-0.05kN. The objective function of the radial basis function neural network response surface model can be set based on the curve residual after the third tensile force displacement curve and the third comparative tensile force displacement curve are truncated, and the curve residual after the fourth tensile force displacement curve and the fourth comparative tensile force displacement curve are truncated, and the weighted coefficients are all 1.

[0167] Based on the radial basis neural network response surface model, a set of fourth parameters to be identified can be determined in the parameter sample set so as to minimize the objective function. After determining the fourth parameters to be identified, the fourth parameters to be identified are optimized based on an optimization algorithm. Any optimization algorithm can be used for optimization, and there is no limitation here. For example, a genetic algorithm (GA) algorithm or a simulated annealing (ASA) algorithm can be used to optimize the fourth parameters to be identified.

[0168] See also Figure 2 and Fig.19 In some embodiments, determining the fourth parameter to be identified (i.e., 0110) of the self-piercing riveting constraint model based on the simulation optimization iterative model also includes:

[0169] 0117: when the curve difference is less than the first threshold and / or the change value of the fourth parameter to be identified is less than the second threshold, outputting the optimized fourth parameter to be identified;

[0170] 0118: When the curve difference is greater than the first threshold and / or the change value of the fourth parameter to be identified is greater than the second threshold, the sample space is reduced based on the sequential response surface method, and the DOE experimental design is returned to the fourth parameter to be identified, and the parameter sample set corresponding to the fourth parameter to be identified is determined in the sample space.

[0171] Specifically, the iterative optimization of the simulation optimization iterative model needs to set a reasonable stopping criterion, and the stopping criterion can be set according to the curve difference and / or the change value of the fourth parameter to be identified. For example, when the curve difference is less than the first threshold value and / or the change value of the fourth parameter to be identified is less than the second threshold value, the iterative optimization of the simulation optimization iterative model is stopped, and the optimized fourth parameter to be identified is output as the optimization result. When the curve difference is greater than the first threshold value and / or the change value of the fourth parameter to be identified is greater than the second threshold value, the sample space is reduced based on the sequence response surface method, and the DOE experimental design is returned to the fourth parameter to be identified, and the parameter sample set corresponding to the fourth parameter to be identified is determined, and the iterative optimization is continued until the stopping criterion is met. That is, the iterative optimization can be stopped when any one of the curve difference and the change value of the fourth parameter to be identified meets the condition. The first threshold value and the second threshold value can be determined according to the actual situation.

[0172] It should be noted that the change value of the fourth parameter to be identified refers to the difference between the fourth parameter to be identified after optimization by the optimization algorithm and the initialized fourth parameter to be identified. Reducing the sample space based on the sequential response surface method can improve the accuracy of the simulation optimization iterative model and reduce the iteration time.

[0173] Since fewer working conditions need to be iterated, and accurate first parameter to be identified, second parameter to be identified and third parameter to be identified have been obtained through the aforementioned implementation, a stable converged value of the fourth parameter to be identified can be quickly obtained through the above iteration steps. Figure 20 to Figure 22 They are the stable convergence processes of displacement scaling coefficients ALPHA1, ALPHA2, and ALPHA3, respectively. It can be seen that they can converge to a stable solution within 10 iterations.

[0174] The identified fourth parameter to be identified is substituted into the self-piercing riveting constraint model for simulation, and the third simulation tensile force displacement curve corresponding to the third angle and the fourth simulation tensile force displacement curve corresponding to the fourth angle are calculated respectively, and the third tensile force displacement curve and the fourth tensile force displacement curve are benchmarked respectively. The benchmarking result of the third angle is as follows: Fig.23 As shown in Figure 2, the alignment result of the fourth angle is as follows: Fig.24 As shown in the figure, it can be seen that the fourth parameter to be identified by the self-piercing riveting parameter identification method according to the embodiment of the present application has a higher accuracy.

[0175] In summary, the first parameter to be identified, the second parameter to be identified, the third parameter to be identified, and the fourth parameter to be identified using the self-piercing riveting parameter identification method according to the embodiment of the present application all have high accuracy.

[0176] In certain embodiments, if there is test data of the peeling condition, the tensile force displacement curve of the peeling sample may be introduced to correct the fourth parameter to be identified, so as to improve the fitting accuracy of the peeling condition.

[0177] See also Fig.25 , the embodiment of the present application also provides a self-piercing riveting parameter identification device 300. The self-piercing riveting parameter identification device 300 includes a design module 310, an acquisition module 320, an establishment module 330, a first determination module 340 and a second determination module 350. The design module 310 is used to design a tensile specimen 100 of a first angle and a second angle, and perform tensile tests respectively, and the second angle is smaller than the first angle. The acquisition module 320 is used to obtain a first tensile force displacement curve corresponding to the first angle and a second tensile force displacement curve corresponding to the second angle through a tensile test. The establishment module 330 is used to establish a self-piercing riveting simplified model 200 based on the self-piercing riveting constraint model. The first determination module 340 is used to determine a first comparative tensile force displacement curve corresponding to the first angle and a second comparative tensile force displacement curve corresponding to the second angle based on the self-piercing riveting simplified model 200. The second determination module 350 is used to determine the first parameter to be identified of the self-piercing riveting constraint model according to the first tensile force displacement curve, the second tensile force displacement curve, the first comparative tensile force displacement curve, and the second comparative tensile force displacement curve.

[0178] In some embodiments, the establishing module 330 is specifically configured to establish the self-piercing riveting simplified model 200 based on the self-piercing riveting constraint model and the rigid connection unit 240 .

[0179] In some embodiments, the second determination module 350 is further configured to determine a second parameter to be identified of the self-piercing riveting constraint model according to the first tensile force-displacement curve; and determine a third parameter to be identified of the self-piercing riveting constraint model according to the second tensile force-displacement curve.

[0180] In some embodiments, the first parameter to be identified includes the rivet tensile failure displacement and / or the displacement ratio corresponding to the maximum tensile force of the rivet, and the second determination module 350 is specifically used to determine the second parameter to be identified of the self-piercing riveting constraint model according to the first tensile force displacement curve; determine the first displacement and the second displacement corresponding to the first angle according to the second parameter to be identified and the first comparative tensile force displacement curve, wherein the first displacement is the master-slave plate displacement when the rivet joint force reaches the maximum tensile force, and the second displacement is the master-slave plate displacement when the rivet joint force decays from the maximum tensile force to zero; determine the first parameter to be identified according to the first displacement and the second displacement.

[0181] In some embodiments, the first parameter to be identified includes the rivet shear failure displacement and / or the displacement ratio corresponding to the maximum shear force of the rivet, and the second determination module 350 is specifically used to determine the third parameter to be identified of the self-piercing riveting constraint model according to the second tensile force displacement curve; determine the third displacement and the fourth displacement corresponding to the second angle according to the third parameter to be identified and the second comparative tensile force displacement curve, wherein the third displacement is the master-slave plate displacement when the rivet joint force reaches the maximum shear force, and the fourth displacement is the master-slave plate displacement when the rivet joint force decays from the maximum shear force to zero; determine the first parameter to be identified of the self-piercing riveting constraint model according to the third displacement and the fourth displacement.

[0182] In some embodiments, the second determination module 350 is also used to design tensile specimens 100 with third angles and fourth angles, and perform tensile tests respectively, the third angle is smaller than the first angle and larger than the second angle, and the fourth angle is smaller than the third angle and larger than the second angle; a third tensile force-displacement curve corresponding to the third angle and a fourth tensile force-displacement curve corresponding to the fourth angle are obtained through the tensile test; a simulation optimization iterative model is established based on the third tensile force-displacement curve and the fourth tensile force-displacement curve; and a fourth parameter to be identified of the self-piercing riveting constraint model is determined based on the simulation optimization iterative model.

[0183] In some embodiments, the second determination module 350 is specifically used to initialize the fourth parameter to be identified; perform DOE experimental design on the fourth parameter to be identified, and determine the parameter sample set corresponding to the fourth parameter to be identified in the sample space; perform finite element analysis on the parameter sample set based on the first parameter to be identified, the second parameter to be identified, and the third parameter to be identified, and determine the third comparative tensile force displacement curve corresponding to the third angle and the fourth comparative tensile force displacement curve corresponding to the fourth angle; calculate the curve difference through the dynamic time warping method according to the third tensile force displacement curve, the fourth tensile force displacement curve, the third comparative tensile force displacement curve, and the fourth comparative tensile force displacement curve; construct a radial basis neural network response surface model according to the parameter sample set and the curve difference; determine the fourth parameter to be identified based on the radial basis neural network response surface model, and optimize the fourth parameter to be identified based on the optimization algorithm.

[0184] In some embodiments, the second determination module 350 is specifically used to output the optimized fourth parameter to be identified when the curve difference is less than the first threshold and / or the change value of the fourth parameter to be identified is less than the second threshold; when the curve difference is greater than the first threshold and / or the change value of the fourth parameter to be identified is greater than the second threshold, reduce the sample space based on the sequential response surface method, and return to the step of performing DOE experimental design on the fourth parameter to be identified, and determining the parameter sample set corresponding to the fourth parameter to be identified in the sample space.

[0185] It should be pointed out that the explanation of the self-piercing riveting parameter identification method in the aforementioned embodiment is also applicable to the self-piercing riveting parameter identification device 300 in the embodiment of the present application, and will not be elaborated here.

[0186] See also Fig.26 The embodiment of the present application also provides a self-piercing riveting parameter identification system 400. The self-piercing riveting parameter identification system 400 includes one or more processors 410 and a memory 420. The memory 420 stores a computer program, and when the computer program is executed by the processor 410, the self-piercing riveting parameter identification method of any of the above embodiments is implemented.

[0187] For example, when the computer program is executed by the processor 410, the following self-piercing riveting parameter identification method is implemented:

[0188] 010: Designing a tensile test specimen 100 with a first angle and a second angle, and performing tensile tests respectively, wherein the second angle is smaller than the first angle;

[0189] 020: obtaining a first tensile force-displacement curve corresponding to the first angle and a second tensile force-displacement curve corresponding to the second angle through a tensile test;

[0190] 030: Establish a simplified model of self-piercing riveting based on the self-piercing riveting constraint model 200;

[0191] 040: Determine a first comparative tensile force displacement curve corresponding to the first angle and a second comparative tensile force displacement curve corresponding to the second angle based on the simplified self-piercing riveting model 200;

[0192] 050: Determine a first parameter to be identified of the self-piercing riveting constraint model according to the first tensile force displacement curve, the second tensile force displacement curve, the first comparative tensile force displacement curve, and the second comparative tensile force displacement curve.

[0193] For another example, when the computer program is executed by the processor 410, the following self-piercing riveting parameter identification method is implemented:

[0194] 031: A simplified self-piercing riveting model 200 is established based on the self-piercing riveting constraint model and the rigid connection unit 240.

[0195] It should be pointed out that the explanations of the self-piercing riveting parameter identification method and the self-piercing riveting parameter identification device 300 in the aforementioned embodiment are also applicable to the self-piercing riveting parameter identification system 400 of the embodiment of the present application, and will not be elaborated here.

[0196] See also Fig. 27 The present application also provides a computer-readable storage medium 500 on which a computer program 510 is stored. When the program is executed by a processor 520, the self-piercing riveting parameter identification method of any of the above embodiments is implemented.

[0197] For example, when the program is executed by the processor 520, the following self-piercing riveting parameter identification method is implemented:

[0198] 010: Designing a tensile test specimen 100 with a first angle and a second angle, and performing tensile tests respectively, wherein the second angle is smaller than the first angle;

[0199] 020: obtaining a first tensile force-displacement curve corresponding to the first angle and a second tensile force-displacement curve corresponding to the second angle through a tensile test;

[0200] 030: Establish a simplified model of self-piercing riveting based on the self-piercing riveting constraint model 200;

[0201] 040: Determine a first comparative tensile force displacement curve corresponding to the first angle and a second comparative tensile force displacement curve corresponding to the second angle based on the simplified self-piercing riveting model 200;

[0202] 050: Determine a first parameter to be identified of the self-piercing riveting constraint model according to the first tensile force displacement curve, the second tensile force displacement curve, the first comparative tensile force displacement curve, and the second comparative tensile force displacement curve.

[0203] For another example, when the program is executed by the processor 520, the following self-piercing riveting parameter identification method is implemented:

[0204] 031: A simplified self-piercing riveting model 200 is established based on the self-piercing riveting constraint model and the rigid connection unit 240.

[0205] It should be noted that the explanations of the self-piercing riveting parameter identification method and the self-piercing riveting parameter identification device 300 in the aforementioned embodiments are also applicable to the computer-readable storage medium 200 of the embodiments of the present application, and will not be further described here.

[0206] In summary, in the self-piercing riveting parameter identification method, identification device 300, identification system 400 and computer-readable storage medium 500 of the embodiment of the present application, a self-piercing riveting simplified model 200 is established based on the self-piercing riveting constraint model, and the first tensile force displacement curve corresponding to the first angle of the tensile specimen 100, the second tensile force displacement curve corresponding to the second angle, and the first comparative tensile force displacement curve corresponding to the first angle of the self-piercing riveting simplified model 200, and the second comparative tensile force displacement curve corresponding to the second angle, the first parameter to be identified is calculated and determined, eliminating the complex iterative process. In this way, the amount of calculation in the parameter identification process is greatly reduced, and the efficiency and accuracy of parameter identification are effectively improved.

[0207] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0208] Any process or method description in a flowchart or otherwise described herein may be understood to represent a module, segment or portion of code that includes one or more executable instructions for implementing the steps of a specific logical function or process, and the scope of the preferred embodiments of the present application includes alternative implementations in which functions may not be performed in the order shown or discussed, including performing functions in a substantially simultaneous manner or in the reverse order depending on the functions involved, which should be understood by technicians in the technical field to which the embodiments of the present application belong.

[0209] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as an ordered list of executable instructions for implementing logical functions, and can be embodied in any computer-readable storage medium for use by an instruction execution system, device or apparatus (such as a computer-based system, a system including a processor, or other system that can fetch instructions from an instruction execution system, device or apparatus and execute instructions), or in combination with these instruction execution systems, devices or apparatuses. For the purposes of this specification, a computer-readable storage medium can be any device that can contain, store, communicate, propagate or transmit a program for use by an instruction execution system, device or apparatus, or in combination with these instruction execution systems, devices or apparatuses. More specific examples (non-exhaustive list) of computer-readable storage media include the following: an electrical connection with one or more wires (electronic device), a portable computer disk box (magnetic device), a random access memory (RAM), a read-only memory (ROM), an erasable and programmable read-only memory (EPROM or flash memory), a fiber optic device, and a portable compact disk read-only memory (CDROM). In addition, the computer-readable storage medium may even be paper or other suitable medium on which the program is printed, since the program may be obtained electronically, for example, by optically scanning the paper or other medium and then editing, interpreting or processing in other suitable ways if necessary, and then stored in a computer memory.

[0210] It should be understood that the various parts of the present application can be implemented by hardware, software, firmware or a combination thereof. In the above-mentioned embodiments, multiple steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented by hardware, as in another embodiment, it can be implemented by any one of the following technologies known in the art or their combination: a discrete logic circuit having a logic gate circuit for implementing a logic function for a data signal, a dedicated integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

[0211] A person of ordinary skill in the art will appreciate that all or part of the steps carried by the method for implementing the above-mentioned embodiment can be completed by instructing the relevant hardware through a program, and the program can be stored in a computer-readable storage medium, which, when executed, includes one or a combination of the steps of the method embodiment. In addition, each functional unit in each embodiment of the present application can be integrated into a processing module, or each unit can exist physically alone, or two or more units can be integrated into one module. The above-mentioned integrated module can be implemented in the form of hardware or in the form of a software functional module. If the integrated module is implemented in the form of a software functional module and sold or used as an independent product, it can also be stored in a computer-readable storage medium. The above-mentioned storage medium can be a read-only memory, a disk or an optical disk, etc.

[0212] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations on the present application. Ordinary technicians in this field can change, modify, replace and modify the above embodiments within the scope of the present application. The scope of the present application is defined by the claims and their equivalents.

Claims

1. A method for identifying parameters of self-piercing riveting, characterized in that: include: Designing tensile specimens with a first angle and a second angle, and performing tensile tests respectively, wherein the second angle is smaller than the first angle; Acquire a first tensile force-displacement curve corresponding to the first angle and a second tensile force-displacement curve corresponding to the second angle through a tensile test; A simplified model of self-piercing riveting is established based on the constraint model of self-piercing riveting; Determine, based on the simplified self-piercing riveting model, a first comparative tensile force-displacement curve corresponding to the first angle and a second comparative tensile force-displacement curve corresponding to the second angle; A first parameter to be identified of the self-piercing riveting constraint model is determined according to the first tensile force-displacement curve, the second tensile force-displacement curve, the first comparative tensile force-displacement curve, and the second comparative tensile force-displacement curve.

2. The self-piercing riveting parameter identification method according to claim 1, characterized in that: The first angle is 90 degrees, and the second angle is 0 degrees.

3. The self-piercing riveting parameter identification method according to claim 1, characterized in that: The self-piercing riveting simplified model is established based on the self-piercing riveting constraint model, including: A simplified model of self-piercing riveting is established based on the self-piercing riveting constraint model and rigid connection unit.

4. The self-piercing riveting parameter identification method according to claim 1, characterized in that: The first parameter to be identified includes any one or more of a rivet tensile failure displacement, a rivet shear failure displacement, a displacement ratio corresponding to a maximum tensile force of the rivet, and a displacement ratio corresponding to a maximum shear force of the rivet.

5. The self-piercing riveting parameter identification method according to claim 4, characterized in that: The first parameter to be identified includes the rivet tensile failure displacement and / or the displacement ratio corresponding to the maximum tensile force of the rivet, and the first parameter to be identified of the self-piercing riveting constraint model is determined according to the first tensile force displacement curve, the second tensile force displacement curve, the first comparative tensile force displacement curve, and the second comparative tensile force displacement curve, including: Determining a second parameter to be identified of the self-piercing riveting constraint model according to the first tensile force-displacement curve; Determine a first displacement and a second displacement corresponding to the first angle according to the second parameter to be identified and the first comparative tensile force-displacement curve, wherein the first displacement is the displacement of the master and slave plates when the rivet joint force reaches a maximum tensile force, and the second displacement is the displacement of the master and slave plates when the rivet joint force decays from the maximum tensile force to zero; The first parameter to be identified is determined according to the first displacement and the second displacement.

6. The self-piercing riveting parameter identification method according to claim 4, characterized in that: The first parameter to be identified includes the rivet shear failure displacement and / or the displacement ratio corresponding to the maximum shear force of the rivet, and the first parameter to be identified of the self-piercing riveting constraint model is determined according to the first tensile force displacement curve, the second tensile force displacement curve, the first comparative tensile force displacement curve, and the second comparative tensile force displacement curve, including: Determining a third parameter to be identified of the self-piercing riveting constraint model according to the second tensile force-displacement curve; Determine a third displacement and a fourth displacement corresponding to the second angle according to the third parameter to be identified and the second comparative tensile force-displacement curve, wherein the third displacement is the displacement of the master and slave plates when the rivet joint force reaches the maximum shear force, and the fourth displacement is the displacement of the master and slave plates when the rivet joint force decays from the maximum shear force to zero; The first parameter to be identified is determined according to the third displacement and the fourth displacement.

7. The self-piercing riveting parameter identification method according to claim 1, characterized in that: The self-piercing riveting parameter identification method further includes: Determining a second parameter to be identified of the self-piercing riveting constraint model according to the first tensile force-displacement curve; A third parameter to be identified of the self-piercing riveting constraint model is determined according to the second tensile force-displacement curve.

8. The self-piercing riveting parameter identification method according to claim 7, characterized in that: The second parameter to be identified includes the maximum tensile force of the rivet, and the third parameter to be identified includes the maximum shear force of the rivet.

9. The self-piercing riveting parameter identification method according to claim 7, characterized in that: The self-piercing riveting parameter identification method further includes: Designing tensile specimens with a third angle and a fourth angle, and performing tensile tests respectively, wherein the third angle is smaller than the first angle and larger than the second angle, and the fourth angle is smaller than the third angle and larger than the second angle; Acquire, by tensile testing, a third tensile force-displacement curve corresponding to the third angle and a fourth tensile force-displacement curve corresponding to the fourth angle; Establishing a simulation optimization iterative model based on the third tensile force-displacement curve and the fourth tensile force-displacement curve; A fourth parameter to be identified of the self-piercing riveting constraint model is determined based on the simulation optimization iterative model.

10. The self-piercing riveting parameter identification method according to claim 9, characterized in that: The third angle is 60 degrees, and the fourth angle is 30 degrees.

11. The self-piercing riveting parameter identification method according to claim 9, characterized in that: The fourth parameter to be identified includes at least one displacement scaling factor.

12. The self-piercing riveting parameter identification method according to claim 9, characterized in that: The determining of the fourth parameter to be identified of the self-piercing riveting constraint model based on the simulation optimization iterative model includes: Initializing the fourth parameter to be identified; Performing a DOE test design on the fourth parameter to be identified, and determining a parameter sample set corresponding to the fourth parameter to be identified in a sample space; Performing finite element analysis on the parameter sample set based on the first parameter to be identified, the second parameter to be identified, and the third parameter to be identified to determine a third comparative tensile force-displacement curve corresponding to the third angle and a fourth comparative tensile force-displacement curve corresponding to the fourth angle; Calculating a curve difference by a dynamic time warping method according to the third tensile force-displacement curve, the fourth tensile force-displacement curve, the third comparative tensile force-displacement curve, and the fourth comparative tensile force-displacement curve; Constructing a radial basis neural network response surface model according to the parameter sample set and the curve difference; The fourth parameter to be identified is determined based on the radial basis neural network response surface model, and the fourth parameter to be identified is optimized based on an optimization algorithm.

13. The self-piercing riveting parameter identification method according to claim 12, characterized in that: The determining of the fourth parameter to be identified of the self-piercing riveting constraint model based on the simulation optimization iterative model further includes: When the curve difference is less than a first threshold value and / or the change value of the fourth parameter to be identified is less than a second threshold value, outputting the optimized fourth parameter to be identified; When the curve difference is greater than the first threshold and / or the change value of the fourth parameter to be identified is greater than the second threshold, the sample space is reduced based on the sequential response surface method, and the step of performing DOE experimental design on the fourth parameter to be identified and determining the parameter sample set corresponding to the fourth parameter to be identified in the sample space is returned.

14. A self-piercing riveting parameter identification device, characterized in that: include: A design module, used for designing tensile specimens with a first angle and a second angle, and performing tensile tests respectively, wherein the second angle is smaller than the first angle; an acquisition module, configured to acquire, through a tensile test, a first tensile force-displacement curve corresponding to the first angle and a second tensile force-displacement curve corresponding to the second angle; Establishing a module for establishing a simplified self-piercing riveting model based on a self-piercing riveting constraint model; A first determination module is used to determine a first comparative tensile force displacement curve corresponding to the first angle and a second comparative tensile force displacement curve corresponding to the second angle based on the simplified self-piercing riveting model; The second determination module is used to determine a first parameter to be identified of the self-piercing riveting constraint model according to the first tensile force displacement curve, the second tensile force displacement curve, the first comparative tensile force displacement curve, and the second comparative tensile force displacement curve.

15. A self-piercing riveting parameter identification system, characterized in that: The self-piercing riveting parameter identification system includes one or more processors and a memory, wherein the memory stores a computer program, and when the computer program is executed by the processor, the self-piercing riveting parameter identification method according to any one of claims 1 to 13 is implemented.

16. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the program is executed by a processor, the self-piercing riveting parameter identification method according to any one of claims 1 to 13 is implemented.

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