Method and Device for Predicting and/or Reducing the Deformation of a Multipart Assembly

Abstract

An apparatus for predicting and/or reducing a deformation of an assembly brought about during production of a weld seam that connects a first component and a second component of the assembly includes a device that is configured to determine and/or provide a finite element (FE) model of the assembly where the FE model includes a set of FEs for the weld seam and a set of FEs for the first component and the second component. The device is further configured to induce a spatial contraction of the set of FEs for the weld seam, determine an effect of the spatial contraction on the set of FEs for the first component and/or the second component, and predict a spatial deformation of the first component and/or of the second component on a basis of the effect on the set of FEs for the first component and/or the second component.

Claims

1.-11. (canceled)

12. An apparatus for predicting and/or reducing a deformation of an assembly (110) brought about during production of a weld seam (203) that connects a first component (201) and a second component (202) of the assembly (110), comprising: a device, wherein the device is configured to: determine and/or provide a finite element (FE) model (310) of the assembly (110), wherein the FE model (310) comprises a set of FEs (311) for the weld seam (203) and a set of FEs (311) for the first component (201) and the second component (202); induce a spatial contraction of the set of FEs (311) for the weld seam (203); determine an effect of the spatial contraction on the set of FEs (311) for the first component (201) and/or the second component (201, 202); and predict a spatial deformation of the first component (201) and/or of the second component (202) on a basis of the effect on the set of FEs (311) for the first component (201) and/or the second component (202).

13. The apparatus according to claim 12, wherein the weld seam (203) extends linearly between the first component (201) and the second component (202) and wherein the set of FEs (311) for the weld seam (203) comprises a linear sequence of FEs (311) that corresponds to the weld seam (203).

14. The apparatus according to claim 12, wherein the device is configured to: bring about a spatial contraction by a contraction factor; and apply the contraction factor to individual FEs (311) of the set of FEs (311) for the weld seam (203); and/or distribute the spatial contraction uniformly over the set of FEs (311) for the weld seam (203).

15. The apparatus according to claim 12, wherein the device is configured to: determine one or more reference properties of the first component (201) and/or of the second component (202); and determine a degree of the spatial contraction to be induced on a basis of the one or more reference properties of the first component (201) and/or the second component (202).

16. The apparatus according to claim 15, wherein the one or more reference properties include: a material of the first component (201) and/or of the second component (202); and/or a material thickness of the first component (201) and/or of the second component (202).

17. The apparatus according to claim 15, wherein: the device is configured to determine the degree of the spatial contraction to be induced on a basis of predetermined characteristic data; and the predetermined characteristic data indicate a respective degree of the spatial contraction to be induced for a multiplicity of combinations of one or more different reference properties of a first reference component and/or a second reference component.

18. The apparatus according to claim 12, wherein the device is configured to: repeatedly adapt the FE model (310) of the assembly (110) for the first component (201) and/or for the second component (202) in order to determine an adapted FE model (310); repeatedly induce a spatial contraction of the set of FEs (311) for the weld seam (203) of the adapted FE model (310); repeatedly determine an effect of the spatial contraction on the set of FEs (311) for the first component (201) and/or the second component (202) of the adapted FE model (310); and repeatedly determine a degree of the spatial deformation of the first component (201) and/or the second component (202) on a basis of the effect on the set of FEs (311) for the first component (201) and/or the second component (202) of the adapted FE model (310); in order to determine an optimized adapted FE model (310) for which the degree of the spatial deformation of the first component (201) and/or the second component (202) is smaller than a predetermined deformation threshold value.

19. The apparatus according to claim 18, wherein the device is configured to provide structural data for the optimized adapted FE model (310) of the assembly (110) that allow production of the first component (201) and/or the second component (202).

20. The apparatus according to claim 18, wherein the device is configured to adapt a geometric form and/or a material property of the first component (201) and/or of the second component (202) in order to determine the adapted FE model (310).

21. The apparatus according to claim 12, wherein the set of FEs (311) for the weld seam (203) describes an entirety of the weld seam (203) between the first component (201) and the second component (202) already at a beginning of an FE simulation for determining the effect of the spatial contraction on the set of FEs (311) for the first component (201) and/or the second component (202).

22. A method (400) for predicting and/or reducing a deformation of an assembly (110) brought about during production of a weld seam (203) that connects a first component (201) and a second component (202) of the assembly (110), comprising the steps of: providing (401) a finite element (FE) model (310) of the assembly (110), wherein the FE model (310) comprises a set of FEs (311) for the weld seam (203) and a set of FEs (311) for the first component (201) and the second component (202); inducing (402) a spatial contraction of the set of FEs (311) for the weld seam (203); simulating (403) an effect of the spatial contraction on the set of FEs (311) for the first component (201) and/or the second component (202); and predicting (404) a spatial deformation of the first component (201) and/or of the second component (202) on a basis of the simulated effect on the set of FEs (311) for the first component (201) and/or the second component (202).

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0033] FIG. 1 shows an exemplary vehicle with a multipart assembly;

[0034] FIG. 2a shows a multipart assembly in a front view;

[0035] FIG. 2b shows a multipart assembly in a side view;

[0036] FIG. 3a shows an exemplary finite element model of a multipart assembly;

[0037] FIG. 3b shows an exemplary finite element; and

[0038] FIG. 4 shows a flow chart of an exemplary method for predicting and/or for avoiding or reducing deformations during the production of a multipart assembly.

DETAILED DESCRIPTION OF THE DRAWINGS

[0039] As presented in the introduction, the present document is concerned with the efficient and timely prediction and, if appropriate, avoidance and/or reduction of deformation during the production of a multipart assembly by means of a welding process. In this context, FIG. 1 shows a vehicle 100 with a vehicle door 110 as an example for a multipart assembly. Furthermore, FIG. 2a schematically shows a multipart assembly 110 in a front view (of the surface of the multipart assembly 110) and FIG. 2b shows the multipart assembly in a side view (of the edge between the different components 201, 202 of the assembly 110). The multipart assembly 110 may have, for example, a surface area of 0.5 m.sup.2 or more.

[0040] The assembly 110 comprises a first component 201, which, for example, is designed to effect the mechanical stability of the assembly 110 (at least to a significant extent). Furthermore, the assembly 110 comprises a second component 202, which, for example, is designed to effect a decorative and/or shaping function of the assembly 110. When the component 110 is a vehicle door, it is possible for example the second component 202 to form an outer skin of the vehicle door. The first component 201 may have a relatively stiff form, while the second component 202 may be relatively easily deformable (e.g., on account of the use of a relatively thin metal sheet).

[0041] The first component 201 and the second component 202 may be connected to one another at one or more (elongate) edges. For example, the first component 201 and the second component 202 may be canted in to one another and/or pressed together at an edge 204. As an alternative or in addition, the first component 201 and the second component 202 may be welded to one another at one or more edges by way of linear weld seams 203 (e.g., by using a laser welding method and/or by using a tactile and/or remote welding method). For example, a respective weld seam 203 may be arranged at two or more edges of the assembly 110.

[0042] The connecting of the two components 201, 202 by way of one or more linear and/or elongate weld seams 203 may lead to stresses within the assembly 110, it being possible that the stresses bring about deformations in particular in the second component 202. The stresses may be caused in particular by the thermal influences in the course of the production and the cooling of the weld seams 203. The stresses and deformations caused thereby may be predicted, if appropriate, by specific measurements made on prototypes of the component 110 and/or by the use of complex thermomechanical simulation models.

[0043] The individual components 201, 202 of an assembly 110 can be described by a finite element (FE) model 310, as illustrated by way of example in FIG. 3a. FIG. 3a shows, in particular, an FE model 310 for a detail of the component 110. In this respect, the first component 201 and the second component 202 are each described by a set of finite elements 311 that adjoin one another and may have, for example, a respective (three-dimensional) beam or cuboid structure. In other words, the volume of the individual components 201, 202 can be described by a two- or three-dimensional sequence of FEs 311.

[0044] Each individual FE 311 may (as illustrated in FIG. 3b) comprise a plurality of parameters, in particular geometric parameters 321, 322 for describing the spatial extent of the FE 311 and/or mechanical parameters 331, 332 for describing mechanical forces and/or tensions within the FE 311. Furthermore, an FE 311 may comprise a mathematical and/or mechanical model that describes how mechanical forces and/or tensions at edges of the FE 311 affect the spatial extent of the FE 311, and/or vice versa. Adjacent FEs 311 may interact with one another via edges which adjoin one another.

[0045] The FE model 310 may also comprise FEs 311 for modeling the one or more weld seams 203 for connecting the first component 201 to the second component 202. The FE model 310 of a weld seam 203 may comprise, for example, a (if appropriate, one-dimensional) sequence of FEs 311. In this case, the FE model 310 of a weld seam 203 is connected at a first (longitudinal) edge to the FE model 310 of the first component 201 and at an oppositely situated second (longitudinal) edge to the FE model of the second component 202 in such a way that a change in a parameter 321, 322, 331, 332 in an FE 311 of the weld seam 203 can have an effect on a parameter 321, 322, 331, 332 in an FE 311 of the first component 201 and/or of the second component 202.

[0046] In the basic state of the FE model 310, it can be assumed, if appropriate, that the FEs 311 of a weld seam 203 do not apply any forces and/or tensions 331, 332 to adjacent FEs 311 of the first component 201 and/or of the second component 202.

[0047] The effects of the welding process on a multipart assembly 110 can be simulated by means of the FE model 310 of the assembly 110. In particular, in the process the FE model 310 of a weld seam 203 can be induced to contract by a specific contraction factor (along the length of the weld seam 203 and/or transversely to the weld seam 203). For this purpose, the spatial extent 321 of the FE 311 of the FE model 310 of the weld seam 203 can be induced to reduce by a specific contraction factor (in the longitudinal direction and/or transversely to the longitudinal direction).

[0048] The contraction factor can be determined in advance by measurements and/or by thermomechanical simulations. In particular, in this respect, a first reference component with one or more first reference properties and a second reference component with one or more second reference properties can be connected to one another via at least one weld seam. Exemplary reference properties are: [0049] the material of a component; [0050] the thickness of a component; and [0051] the modulus of elasticity of a component.

[0052] Characteristic data (e.g., in the form of a lookup table) which indicate the contraction factor to be used in each case for different combinations of first and second reference components can then be provided. In order to determine the contraction factor for a specific assembly 110, the reference properties of the first component 201 and the reference properties of the second component 202 can be determined, and then the value of the contraction factor can be determined from the characteristic data on the basis of the reference properties.

[0053] The contraction of the FEs 311 of the weld seam 203 brings about changes in the parameters 321, 322, 331, 332 of the FEs 311 of the first component 201 and/or the second component 202, which parameters can be determined on the basis of the FE model 310 of the assembly 110 in the course of an FE simulation. In particular, effects on the geometric parameters 321, 322 of the Fes 311 of the first component 201 and/or the second component 202 and therefore deformations of the first component 201 and/or of the second component 202 can be determined in the process.

[0054] It can therefore be determined on the basis of an FE simulation whether the generation of one or more weld seams 203 will lead to a (visible) distortion or to a (visible) deformation of the first component 201 and/or of the second component 202. If this is the case, a change can be made to the first component 201 and/or the second component 202 (in particular to the FE model 311 of the first and/or second component 201, 202). In the process, it is possible to adapt, for example, a material property (e.g., the material thickness) and/or the form of the first and/or the second component 201, 202. It is then possible to bring about a renewed contraction of the adapted FE model 310 of the one or more weld seams 203, in order to detect a possible deformation of the assembly 110. This adaptation process can be iteratively repeated.

[0055] An iterative adaptation of the FE model 310 of the first and/or of the second component 201, 202 makes it possible to determine an optimized FE model 310 for which no deformations or no significant (visible) deformations of the first and/or of the second component 201, 202 of the FE model 310 are brought about during the contraction of the one or more weld seams 203. The first and/or the second component 201, 202 and also the multipart assembly 110 can then be manufactured in a manner corresponding to the determined, optimized FE model 310. This makes it possible to efficiently and reliably produce a multipart assembly 110 with one or more weld seams 203, which do not have any deformations (that are significant and/or visible to the naked eye).

[0056] An assembly 110 may thus be virtually modeled in the initial state (by means of a CAD nominal geometry) before production of the one or more weld seams 203. In this respect, only the elements or components 201, 202 of the assembly 110 and not the installation elements and/or tool elements taking part in the process are modeled. In this respect, all weld seams 203 are part of the model 310 (e.g., in each case in the form of a line in the model 310). Data with respect to the tools and/or the installations for the generation of the weld seams 203 are not used. A weld seam 203 can be modeled here by means of finite elements 311 having material data with respect to properties of the material of the weld seam 203.

[0057] To simulate the welding process, the lengths of the one or more weld seams 203 are mechanically (without using heat sources and/or heat sinks) shrunk by a proportion as a percentage (i.e., by a contraction factor). In the process, in the course of the simulation a temporally distributed volume shrinkage as a percentage can be performed. The shrinkage may be applied in a distributed manner along the longitudinal propagation of a weld seam 203. An FE simulation of this type makes it possible to qualitatively and quantitatively assess the susceptibility of the assembly 110 to the emergence of warpages and/or to puncture problems. Furthermore, risk analyses for deformations that may result from other influences can be carried out.

[0058] FIG. 4 shows a flow chart of an exemplary (computer-implemented) method 400 for predicting and/or for reducing the deformation of an assembly 110 brought about during production of at least one (linear) weld seam 203 for connecting a first component 201 and a second component 202 of the assembly 110. The weld seam 203 may be produced, for example, by means of a welding tool, in particular using a laser welding process and/or by use of a tactile and/or remote welding process. The method 400 may be carried out by a computer and/or server (e.g., using an FE simulation software program and/or a CAD (Computer Aided Design) software program).

[0059] The method 400 includes the providing 401 of an FE model 310 of the assembly 110, the FE model 310 comprising a set of FEs 311 for the weld seam 203 and at least one set of FEs 311 for the first and the second component 201, 202. The set of FEs 311 for the weld seam 203 may comprise a linear sequence of FEs 311. In this respect, the FEs 311 of the weld seam 203 may be coupled in each case to at least one FE 311 of the first component 201 and one FE 311 of the second component 202, in particular in such a way that a deformation (in particular a contraction) of an FE 311 of the weld seam 203 brings about a tension and/or a force in an FE 311 of the first component 201 and/or of the second component 202.

[0060] Moreover, the method 400 comprises the inducing 402 of a spatial contraction of the set of FEs 311 for the weld seam 203. In this respect, the contraction may be effected along the linear propagation of the weld seam 203. In particular, the length of the weld seam 203 can be induced to reduce by a specific contraction factor. The reduction of the length of the weld seam 203 may be distributed (uniformly) over the individual FEs 311 for the weld seam 203.

[0061] The method 400 also includes the simulating 403 of the effect of the spatial contraction of the set of FEs 311 for the weld seam 203 on the set of FEs 311 for the first and/or the second component 201, 202. In particular, a simulation can be carried out (by means of an FE simulation program) as to which stresses 331, 332 and/or which spatial changes 321, 322 are brought about in the case of the individual FEs 311 of the first component 201 and/or the second component 202.

[0062] Moreover, the method 400 includes the predicting and/or forecasting 404 of the spatial deformation of the first component 201 and/or the second component 202 on the basis of the simulated effect on the set of FEs 311 for the first and/or the second component 201, 202.

[0063] The method 400 described makes it possible to efficiently (also without using a model of the welding installation and/or of the welding process) make a prediction as to what effect the welding process will have on the deformation of a multipart assembly 110. Furthermore, an iterative and/or repeated adaptation of the FE model 310 of the assembly 110 makes it possible to determine an FE model 310 in which the contraction of the weld seam 203 leads to a reduced deformation of the first and/or of the second component 201, 202. The first and/or the second component 201, 202 may then be manufactured on the basis of the adapted FE model 310, with the result that an assembly 110 can be produced with reduced deformations.

[0064] The present invention is not restricted to the exemplary embodiments shown. In particular, it should be noted that the description and the figures are intended to illustrate only the principle of the methods, devices and systems provided.