JP2015088062A - Analysis model creation device, analysis model creation program, and analysis model creation method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To shorten a time used in creating an analysis model and heighten the accuracy of analysis.SOLUTION: An analysis model creation device according to an embodiment has the configuration below. A first division processing unit divides the whole area corresponding to the shape of an object to be analyzed into a plurality of first divided elements having a uniform shape. A second division processing unit divides an edge section of the whole area corresponding to the shape of the object to be analyzed into a plurality of second divided elements having a discretionarily determined shape. A displacement information setting unit sets, on the basis of the relative physical relationship of the mutual nodal points of the first and second divided elements having an overlapping area, information relating to the displacement of the mutual nodal points when a stress is applied to the object to be analyzed. A rigidity information setting unit sets, on the basis of the degree of duplication, with each other, of the first and second divided elements having an overlapping area, information relating to rigidity for the divided elements having the overlapping area. An analysis model creation processing unit takes in the set information relating to displacement and information relating to rigidity and creates an analysis model.

Description

  Embodiments described herein relate generally to an analysis model creation device, an analysis model creation program, and an analysis model creation method.

  Structural analysis using an analysis model is useful for evaluating the soundness and strength of a structure. Large-scale analysis that obtains results by directly modeling complex shapes as an analysis model has been actively incorporated into product design and development due to recent improvements in computer performance and development of analysis technology.

  However, large-scale analysis requires enormous time and labor to create an analysis model. In particular, in the structural analysis and fluid analysis of complicated shapes, the time required to create an analysis model may be longer than the analysis time. Therefore, the analysis model creation time often becomes a rule factor (bottleneck) of lead time in product development and design.

  Usually, when an analysis model of a three-dimensional shape is created, the analysis space of the analysis object of the three-dimensional shape is divided into elements using the three-dimensional CAD data. The analysis model obtained through the element division or the like is subjected to numerical analysis after boundary conditions and the like are set, and an analysis result is output. Here, enormous time and labor for creating the analysis model are often required when the analysis space is divided into elements. For example, if an element having a distorted shape is used for element division, the analysis accuracy is greatly reduced. In such a case, the element division is performed manually by a technician having expertise.

  In view of the above problems, an auto mesh technique for automatically dividing an element has been developed. An ultra-high-speed mesh generator, which is an example of auto-mesh software, can significantly reduce the work time for element division and reduce the work time to, for example, 1/3 to 1/20 or less of the conventional method. is there.

  As another example of the auto mesh technique, a voxel element technique is known. The voxel element technology can create an analysis model in a short time by using regular lattice units (voxels) having a regular shape in a three-dimensional space. For example, the shape data defining the surface shape of the analysis object is divided into voxel elements and converted into an analysis model.

  Analytical modeling with voxel elements uses limited-shaped elements, so the element formation time is overwhelmingly short compared to analytical modeling with arbitrary-shaped elements, and analysis accuracy is easily secured and managed. . On the other hand, the edge (surface) of the analysis model is disadvantageous, for example, because it is difficult to align the curved surface of an arbitrary shape and the boundary of the voxel element, which may cause a boundary condition setting error and a decrease in analysis accuracy. There is. In particular, in the field of structural analysis, the frequency of evaluating stress values at the edges of structures where stress concentration is likely to occur is high. Therefore, a decrease in analysis accuracy at the edge of the analysis model can be said to be a major drawback when the voxel element technology is used.

  In order to avoid such drawbacks, a technique for automatically correcting the shape of the voxel element located at the edge of the analysis model by detecting the intersection where the edge of the analysis object cuts the voxel element has been proposed. Yes. This technique ensures a certain level of analysis accuracy. However, since the voxel elements are locally distorted at the edge of the analysis model, it is difficult to ensure and manage the analysis accuracy.

  In view of this, a superposition mesh method in which an element separate from the voxel element is arranged so as to overlap the voxel element at the edge of the analysis model has been proposed. In the numerical analysis in which the superposition mesh method and the finite covering method are integrated, it is possible to suppress a decrease in the analysis accuracy of the finite covering method alone at the edge of the analysis model. As a result, the analysis error is suppressed to, for example, about 1.6% in the two-dimensional problem (two-dimensional numerical analysis), and the analysis error is suppressed to, for example, about 2.4% in the three-dimensional problem (three-dimensional numerical analysis). And very good analysis accuracy can be obtained.

  However, the numerical analysis that integrates the superposition mesh method and the finite covering method has a larger load of convergence calculation (iterative calculation) than the conventional finite element method, and the analysis time is inevitably longer. Application to analysis is difficult, and further improvements are desired.

JP 2000-182081 A Japanese Unexamined Patent Publication No. 2000-194881 Japanese Patent No. 3272830

Mamoru Tanaka et al., “Manufacturing Innovation Utilizing Numerical Simulation to Improve Productivity”, Mitsubishi Heavy Industries Technical Review, Vol.48, No.1, pp.61-64 (2011). Toshifumi Shimamura et al., “Analysis by Finite Cover Method and Superposition Mesh Method”, Proceedings of the Lecture on Computational Engineering, Vol.10, pp375-376 (2005). Suzuki Katsuyuki et al., “Improvement of accuracy of finite covering method in superposition mesh method”, Proceedings of the 18th Japan Society of Mechanical Engineers, pp.177-178 (2005).

  As described above, for example, in large-scale structural analysis used to evaluate the soundness and strength of structures, the creation time of analysis models is short, the analysis accuracy is high, and the calculation time is short. No analysis method has been found yet. In particular, an analysis method that can shorten the creation time of an analysis model by using voxel element technology and obtains excellent analysis accuracy and analysis convergence has not been established yet.

  Accordingly, the problem to be solved by the present invention is to provide an analysis model creation device, an analysis model creation program, and an analysis model creation method that can shorten the creation time of an analysis model and increase the analysis accuracy.

  The analysis model creation apparatus according to the embodiment includes a first division processing unit, a second division processing unit, a displacement information setting unit, a stiffness information setting unit, and an analysis model creation processing unit. The first division processing unit divides the entire region corresponding to the shape of the analysis object into a plurality of first division elements having a uniform shape. A 2nd division | segmentation process part divides | segments the edge part of the whole area | region corresponding to the shape of the said analysis target object into several 2nd division elements which have the shape defined arbitrarily. The displacement information setting unit, based on the relative positional relationship between the nodes of the first and second divided elements having an overlapping region, when the stress is applied to the analysis object, Set information about displacement. The rigidity information setting unit sets information on rigidity for the divided element having the overlapped area based on the degree of overlap between the first and second divided elements having the overlapped area. The analysis model creation processing unit creates the analysis model by taking in the information on the set displacement and the information on the rigidity.

1 is a block diagram showing a configuration of a structural analysis system including an analysis model creation device according to a first embodiment. The figure which shows an example of the CAD data which the analysis model creation apparatus of FIG. 1 acquires. The figure which shows the state which divided | segmented the whole area | region corresponding to the shape of the analysis target object obtained from CAD data of FIG. 2 by the internal element. The figure which shows the state which divided | segmented the designated range in the edge part of the whole area | region corresponding to the shape of the analysis target object of FIG. 3 by the surface element. The flowchart which shows the process by the analysis model production apparatus of FIG. The figure for demonstrating the coordinate value of the mutual node of the internal element and surface element which have an overlapping area | region, and its displacement. The figure which illustrated the degree of overlap with an internal element and a surface element. The figure which illustrated the analysis result of the analysis subject by the analysis model creation device of Drawing 1. The figure which illustrated the analysis result of the analysis subject by the analysis model creation device of a comparative example. The figure which shows the verification example of the analysis precision by the analysis model creation apparatus of FIG. The block diagram which shows the structure of the structural analysis system containing the analysis model production apparatus which concerns on 2nd Embodiment. The block diagram which shows the structure of the structural analysis system containing the analysis model production apparatus which concerns on 3rd Embodiment. The figure which illustrated the case where the degree of overlap with an internal element and a surface element is large. FIG. 14 is a detailed view of part A in FIG. 13. The figure for demonstrating the correction method of the elasticity modulus according to the ratio with which an internal element and a surface element overlap. The figure which shows an example of the state in which an internal element and a surface element overlap in a coordinate system. The figure which shows the other example of the state in which an internal element and a surface element overlap in a coordinate system. The figure which shows the further another example of the state in which an internal element and a surface element overlap in a coordinate system. The figure which shows the other example different from FIGS. 16-18 of the state in which an internal element and a surface element overlap in a coordinate system. The figure which shows the verification example of the analysis precision by the analysis model production apparatus of FIG.

Hereinafter, embodiments will be described with reference to the drawings.
<First Embodiment>
As shown in FIG. 1, the structural analysis system 15 according to the present embodiment includes an analytical model creation device 20, a structural analysis processing unit 27, and an analysis result output unit 28. As shown in FIG. 1, the analysis model creation apparatus 20 includes a CAD (Computer Aided Design) data acquisition unit 26, a first division processing unit 21, a second division processing unit 22, a displacement information setting unit 23, and a stiffness information setting unit 24. And an analysis model creation processing unit 25.

  Here, the analysis model creation device 20 is equipped with various types of hardware such as a main memory such as a RAM, an auxiliary (secondary) storage device such as an HDD, a CPU, and a ROM. The analysis model creation device 20 loads an analysis model creation program stored in advance in an external (auxiliary) storage device, a ROM, or the like onto the main memory, whereby the first division processing unit 21, the second division processing unit 22, and the displacement Each of the above-described components including the information setting unit 23 is realized by software, for example. Note that these components may be configured by hardware instead of software.

  2 to 4 illustrate two-dimensional analysis modeling in order to facilitate understanding of the technical concept of the present embodiment. FIG. 2 shows an example of CAD data of an analysis object having a substantially L-shaped shape. As shown in FIG. 2, the evaluation site 3 evaluated by the structural analysis is a concave portion where stress concentration can occur.

  As shown in FIGS. 1, 2, and 5 (S1 in FIG. 5), the CAD data acquisition unit 26 acquires CAD data. As shown in FIG. 2, the CAD data includes a plurality of coordinate data 1 and shape data 2 that connects the coordinate data. The CAD data acquisition unit 26 obtains a region (coordinate space) corresponding to the shape of the analysis target object from the coordinate data 1 and the shape data 2.

  As shown in FIG. 1, FIG. 3, FIG. 5 (S2 in FIG. 5), the first division processing unit 21 has a plurality of (finite number) of all regions corresponding to the shape of the analysis object having a uniform shape. Are divided into internal elements 4 (first divided elements). As illustrated in FIG. 3, the first division processing unit 21 performs element division by applying a quadrilateral element (square element) that is a regular lattice unit having a uniform shape and size as the internal element 4. A square element (pixel element) in the case of two-dimensional analysis corresponds to a hexahedral element (voxel element) in the case of three-dimensional analysis.

  Since the first division processing unit 21 applies the internal elements 4 having a uniform shape and size to perform modeling including element division, the first division processing unit 21 can perform automatic processing using existing software or the like, and can perform a very short time. This completes the process. Modeling including such element division by the first division processing unit 21 includes processing for setting an initial value of the elastic modulus for each divided internal element 4.

  As shown in FIGS. 1, 4, and 5 (S3 in FIG. 5), the second division processing unit 22 has a shape in which the edge of the entire region corresponding to the shape of the analysis target is arbitrarily determined. Dividing into a plurality (finite number) of surface elements (second dividing elements) 5. That is, as shown in FIG. 4, the second division processing unit 22 performs modeling smoothly using the plurality of surface elements 5 along the surface shape of the analysis object.

  Specifically, the second division processing unit 22 has a range specified by an input operation to the main body of the analysis model creation apparatus 20 (an evaluation part to be a recess) at the edge of the entire region corresponding to the shape of the analysis object. 3) is divided into a plurality of surface elements 5. The position where the surface element 5 is arranged can be arbitrarily specified by the analyst himself such as a place where analysis accuracy is required or a place where boundary conditions are required.

  As shown in FIG. 4, the surface element 5 uses a rectangular element having an arbitrary shape. The quadrangular element in the case of three-dimensional analysis corresponds to a hexahedral element in the case of three-dimensional analysis. It is also possible to apply a shell element having a shape restriction to the surface element 5. Here, each process by the first division processing unit 21 and the second division processing unit 22 is based on the acquired CAD data to create a shell element or a solid element with a thickness, such as a pre-post processor. Do through. Thereby, it becomes possible to specify an evaluation part arbitrarily and to model quickly.

  As shown in FIGS. 1 and 5 (S4 in FIG. 5) to FIG. 7, the displacement information setting unit 23, the stiffness information setting unit 24, and the analysis model creation processing unit 25 perform the above-described internal element 4 and surface element 5 together. Execute the concatenation process to concatenate. This connection process is a step of automatically correcting so that an appropriate value can be obtained even if the analysis result is obtained while the internal element 4 and the surface element 5 are overlapped.

  Here, as shown in FIGS. 1 and 6, the displacement information setting unit 23 connects the nodes of the internal element 4 and the surface element 5 so that the mutual displacement can be transmitted. In other words, the displacement information setting unit 23 is configured so that the mutual nodes when the stress is applied to the analysis object based on the relative positional relationship between the mutual nodes of the internal element 4 and the surface element 5 having overlapping regions. Set information about displacement.

  On the other hand, as shown in FIGS. 1 and 7, the stiffness information setting unit 24 sets material characteristics in consideration of an overlapping portion (overlapping portion) where the internal element 4 and the surface element 5 overlap, and the overlapping portion So that the amount of deformation becomes an appropriate value that eliminates the effect of overlapping elements. In other words, the stiffness information setting unit 24 sets information related to stiffness for the divided element having the overlapping region based on the degree of overlap between the first and second divided elements having the overlapping region.

  First, the process by the displacement information setting unit 23 will be described with reference to FIG. The coordinates of the node of the internal element 4 (connected node) and the node of the surface element 5 (connected node) are different. Therefore, when the stress is applied to the analysis target, it is desirable that the displacement amount of both the connected node and the connected node is set in consideration of the difference in coordinates and the analysis error caused thereby. Here, the displacement information setting unit 23 calculates the displacement amount of the mutual nodes (connected nodes and connected nodes) of the internal element 4 and the surface element 5 having overlapping regions when stress is applied to the analysis object. Set using the shape function of the finite element method.

FIG. 6 shows an example using a shape function of a two-dimensional isoparametric element as an example in a two-dimensional problem (two-dimensional numerical analysis). As shown in FIG. 6, the displacement (υ, ν) at the coordinate values (η, ξ) of the connected nodes on the surface element 5 side is, for example, the coordinate values (x _i , y) of the four connected nodes on the internal element 4 side. _Using the displacement (ν _i , ν _i ) in _i ), it can be expressed by the following equation [1].

In the above formula [1], N _{1 to} N ₄ are given by the following formula [2] to formula [5]. The coordinate values (x _i , y _i ) of the connected nodes use the element local coordinate system defined by x _i = −1 to 1, y _i = −1 to 1.

N ₁ = (1-η) · (1-ξ) / 4 Formula [2]
N ₂ = (1 + η) · (1−ξ) / 4 Formula [3]
N ₃ = (1 + η) · (1 + ξ) / 4 Formula [4]
N ₄ = (1−η) · (1 + ξ) / 4 Formula [5]

  That is, the displacement information setting unit 23 applies the above equations [1] to [5] to connect the connection node on the inner element 4 side and the connected node on the surface element 5 side to each other (the connection node and the connection node). Displacement that satisfies the discretization assumption of a finite element can be performed, and high-precision analysis can be expected. In addition, when using a high-order element for the internal element 4, an analysis precision can be raised by using the element shape function matched with it.

  Next, processing by the rigidity information setting unit 24 will be described with reference to FIG. If the same stiffness value as that of the constituent material of the original analysis object is assigned to each of the internal element 4 and the surface element 5, the overlapping portion has a higher stiffness value than the actual material, and an analysis error occurs. Therefore, in order to reduce this analysis error, the stiffness information setting unit 24, as shown in FIG. 7, is based on the degree of overlap between the internal element 4 and the surface element 5 having overlapping regions (overlapping portions 8). The elastic modulus (rigidity value) is set (reset) for the internal element 4 having the overlapping region (by determining the overlapping degree of the overlapping parts).

That is, as shown in FIG. 7, the stiffness information setting unit 24 includes the internal element i (internal element 9), the original area S of the internal element i, and the area S _dup of the overlapping part (overlapping part) in the internal element i. Is used to determine an elastic modulus (elastic modulus) E _i such as a longitudinal elastic modulus in the internal element i based on the following equation [6], and the elastic modulus E _i is reset for the internal element i. . However, in Formula [6], E is the original elastic modulus (longitudinal elastic modulus etc.) of the steel grade which is a constituent material of an analysis object.

E _i = {1− (S _dup / S)} × E (6)

More specifically, the stiffness information setting unit 24 uses the area ratio (S _dup / S) to set the stiffness value lower than the initial value, thereby changing the stiffness of the overlapping portion to the stiffness of the non-overlapping portion. Approximate. As shown in FIG. 6, the two-dimensional problem (two-dimensional numerical analysis) is targeted. However, when the three-dimensional problem (three-dimensional numerical analysis) is targeted, the stiffness information setting unit 24 is duplicated. The elastic modulus E _i is corrected using the volume ratio of the portion. Improvement of analysis accuracy is expected by resetting the rigidity value in consideration of the overlapping portion 8 between the internal element 4 and the surface element 5.

  Further, the process by the displacement information setting unit 23 and the process by the stiffness information setting unit 24 are a list of the coordinate values of each node obtained after the element division of the internal element 4 and the surface element 5 and the node numbers constituting each element. Based on the above, it can be automatically performed by the main body of the analysis model creation apparatus 20. For this reason, the connection process mentioned above can be completed in a short time without requiring labor of an analyst. The analysis model creation processing unit 25 creates an analysis model by taking in information (displacement amount) related to displacement set by the displacement information setting unit 23 and information (elastic modulus) related to stiffness set by the stiffness information setting unit 24.

  As shown in FIG. 1 and FIG. 5 (S5 in FIG. 5), the structural analysis processing unit 27 determines boundary conditions and constraint conditions, and uses the analysis model created by the analysis model creation device 20 to use the finite element method. Perform structural analysis. That is, since the structural analysis processing unit 27 can apply a general finite element solver (software for numerical analysis), it can make use of the analysis environment and knowledge that have been used conventionally. In addition, since the analysis using the created analysis model does not cause a new convergence calculation flow, for example, the calculation time is completed within a practical range.

  As shown in FIG. 1, FIG. 5 (S <b> 6 in FIG. 5), and FIG. 8, the analysis result output unit 28 outputs the analysis result of the analysis model analyzed by the structural analysis processing unit 27. Here, FIG. 9 shows, as a comparative example, an analysis result based on a conventional analysis model created with only a plurality of rectangular elements having arbitrarily defined shapes as a true value. As shown in FIG. 8, in the structural analysis system 15 of this embodiment, the stress concentration that can occur in the recess (evaluation site) is accurately reproduced, and it can be confirmed that an excellent analysis result is obtained.

  Further, in the elastic analysis in which various stress values are given as boundary conditions, as shown in FIG. 10, the analysis result (analysis value in FIG. 10) by the structural analysis system 15 of this embodiment is a true value (analysis by a comparative example). It can be confirmed that the analysis accuracy is approximately ± 10% (comparison result of Mises stress in the recess) with respect to the result, and the analysis time of this embodiment is approximately the same as that of the comparative example. .

  As described above, according to the analysis model creation device 20 according to the present embodiment, the creation time of the analysis model can be shortened and the analysis accuracy and the analysis convergence can be improved.

<Second Embodiment>
Next, a second embodiment will be described with reference to FIG. In FIG. 11, the same components as those in FIG. 1 described in the first embodiment are given the same reference numerals, and redundant descriptions are omitted. As shown in FIG. 11, the structural analysis system 30 including the analysis model creation device 40 according to the present embodiment is replaced with the second division processing unit 22 provided in the analysis model creation device 20 of the first embodiment. A second division processing unit 42 is provided.

  The second division processing unit 42 divides the entire peripheral portion of the entire region corresponding to the shape of the analysis object into the plurality (finite number) of surface elements (second division elements). That is, the analyzer (operator) does not manually set the position (range of the evaluation site) where the surface element is arranged, but the second division processing unit 42 automatically sets all the surfaces of the analysis model using the surface element. Covering simplifies the creation of the analysis model and reduces human labor.

  The second division processing unit 42 performs automatic division so that the length of one side of the surface element is in the range of 0.5 to 1.5 times the length of one side of the internal element. Instead, the analyst may arbitrarily specify the size of the surface element. Further, the second division processing unit 42 pushes out surface elements such as shell elements and beam elements toward the inside of the analysis object, and creates surface elements in the thickness direction of the analysis object. The thickness for extruding the surface element may be arbitrarily specified by the analyst. The shape of the surface element is desirably a square (a cube if it is a three-dimensional problem).

  The second division processing unit 42 automatically sets the number of element divisions in the thickness direction of the analysis target to be 1, for example, to reduce the time required for element division. Instead of this, the number of element divisions in the thickness direction may be designated. Note that, after the processing by the second division processing unit 42 is completed, a region where the surface elements overlap is generated. For the overlapping region, the overlapping is automatically corrected by using mesh morphing, which is a known technique.

  As described above, according to the analysis model creation device 40 of the present embodiment, compared to the analysis model creation device 20 of the first embodiment, the analyst can save time and effort to specify the evaluation part (position where the surface element is arranged). Since it can be omitted, it is possible to expect both the rapid creation of the analysis model and the improvement of the analysis accuracy.

<Third Embodiment>
Next, a third embodiment will be described with reference to FIGS. In FIG. 12, the same components as those in FIG. 1 described in the first embodiment are given the same reference numerals, and redundant descriptions are omitted. As shown in FIG. 12, the structural analysis system 50 including the analysis model creation device 60 according to the present embodiment replaces the stiffness information setting unit 24 included in the analysis model creation device 20 of the first embodiment with a stiffness. An information setting unit 64 is provided.

  In the present embodiment, the overlapping area between the internal element and the surface element is specified by the coordinate system. The stiffness information setting unit 64 sets (resets) the longitudinal elastic modulus and the transverse elastic modulus for the internal element having the overlapped area based on the coordinate value of the overlapped area between the internal element and the surface element.

  Specifically, the first and second embodiments modify the elastic modulus of the internal element using the area ratio of the area of the surface element that overlaps the internal element (or the volume ratio of the overlapping volume). The internal element was analyzed as an isotropic elastic body considering the overlap. Although excellent analysis results can be obtained by the analysis methods of the first and second embodiments, as shown in FIGS. 13 and 14, the periphery of the internal element 11 having a large overlap with the surface element 5 is shown. Therefore, the analysis accuracy tends to decrease. Therefore, the stiffness information setting unit 64 of the analysis model creating apparatus 60 according to the third embodiment uses the anisotropic elastic coefficient based on the overlapping shape of the inner element and the surface element to calculate the rigidity factor of the inner element. Correct (correct elastic modulus).

FIG. 15 is a conceptual diagram showing a method of correcting the rigidity factor by the rigidity information setting unit 64. In FIG. 15, for simplicity of explanation, the surface element 12 and the inner element 14 are both square elements of the same size (A × Amm) by a two-dimensional model, and overlapped portion 13 is overlapped by A−B mm in the Y-axis direction. This is an example in which there is a distortion and distortion occurs in the X-axis direction. The elastic modulus (Young's modulus / longitudinal elastic modulus) in the X direction of each of the surface element 12 and the internal element 14 is defined as E ₁₁ ^S and E ₁₁ ^I.

As shown in FIG. 15, first, as an ideal state, it is assumed that the rigidity of the overlapping portion (overlapping portion) 13 on the internal element 14 side is zero. In this case, when a load G is applied to the analysis model in the X direction, each of the surface element 12 and the internal element 14 has a load corresponding to a rigid cross-sectional area (the cross-sectional length in FIG. 15). Distributed to each node. As shown in FIG. 15, the strain (ε ₁₁ ^S , ε ₁₁ ^I ) generated in the surface element 12 and the internal element 14 by these loads is a case where the entire internal element has a constant stiffness value in accordance with the analysis constraints. Assuming calculation, the values obtained by the following equations [6] to [11] are obtained.

G _F = G · A / (A + B) · 0.5 Formula [6]
G _H = G · B / (A + B) · 0.5 Formula [7]
G _J = G · A / (A + B) · 0.5 Formula [8]
G _K = G · B / (A + B) · 0.5 Formula [9]

内部要素のひずみ：

Surface element strain:

Internal element strain:

Here, in order to simulate the deformation in the ideal state, that is, when the internal element rigidity of the overlapping portion 13 is zero, the strains ε ₁₁ ^S and ε ₁₁ ^{I in the} equations [10] and [11] are used. Are considered to be equivalent. Using the above concept, the stiffness information setting unit 64 corrects and calculates the longitudinal elastic modulus (longitudinal elastic modulus) and the transverse elastic modulus (lateral elastic modulus) from the dimension value (overlapping coordinate value) of the overlapping portion 13. Thus, it is possible to obtain a highly accurate analysis result.

In the present embodiment, an example in which the internal rigidity is corrected based on FIG. 15, Expression [10], and Expression [11] using the representative dimension in the X-axis direction and the representative dimension in the Y-axis direction is shown. Taking a two-dimensional problem (two-dimensional numerical analysis) as an example, as shown in FIGS. 16 to 19, a pattern in which an overlapping portion 10 is generated by overlapping surface elements with respect to an internal element 9 (internal element i) is as follows. It can be roughly divided into 4 patterns. The rigidity information setting unit 64 takes overlapping dimensions L _i1 , L _i2 , L _j1 , L _j2 for each, and uses the following formulas [12] to [20] to represent the representative dimensions L _i , L _j. And the anisotropic elastic modulus is calculated.

＜Ｌjの導出方法＞

<Method for deriving Li>

<Lj derivation method>

  FIG. 20 shows an analysis result (analysis value) using an analysis model created by the analysis model creation device 60 of the present embodiment, and a plurality of arbitrarily defined shapes as a comparative example as in the first embodiment. The analysis result (true value) using the conventional analysis model created only with the quadrilateral element is compared with the analysis accuracy verification result. As shown in FIG. 20, it is understood that excellent analysis accuracy is obtained in this embodiment.

  Therefore, according to the analysis model creation device 60 of the present embodiment, as exemplified in the equations [12] to [20], the rigidity is determined as the anisotropic linear expansion coefficient using the representative dimension values (vertical length). By re-setting the elastic modulus and the transverse elastic modulus to the internal element in which the overlapping portion exists, it is possible to achieve both shortening of the analysis model creation time and improvement of the analysis accuracy.

  According to at least one embodiment described above, the analysis model creation time can be shortened and the analysis accuracy can be increased.

  As mentioned above, although some embodiment of this invention was described, these embodiment is shown as an example and is not intending limiting the range of invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the spirit of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

  For example, the second division processing unit 22 provided in the analysis model creation device 60 of the third embodiment is replaced with the second division processing unit 42 provided in the analysis model creation device 40 of the second embodiment. An analysis model creation device may be configured.

  DESCRIPTION OF SYMBOLS 1 ... Coordinate data, 2 ... Shape data, 3 ... Evaluation part (concave part), 4, 9, 11, 14 ... Internal element, 5, 12 ... Surface element, 6 ... Connected node, 7 ... Connection node, 8, 10 , 13 ... Overlapping part, 15, 30, 50 ... Structural analysis system, 20, 40, 60 ... Analytical model creation device, 21 ... First division processing part, 22, 42 ... Second division processing part, 23 ... Displacement information setting , 24, 64 ... rigidity information setting unit, 25 ... analysis model creation processing unit, 26 ... CAD data acquisition unit, 27 ... structural analysis processing unit, 28 ... analysis result output unit.

Claims (8)

A first division processing unit that divides the entire region corresponding to the shape of the analysis object into a plurality of first division elements having a uniform shape;
A second division processing unit that divides an edge portion of the entire region corresponding to the shape of the analysis object into a plurality of second division elements having an arbitrarily defined shape;
Based on the relative positional relationship between the nodes of the first and second divided elements having overlapping regions, information relating to the displacement of the nodes when the stress is applied to the object to be analyzed is set. A displacement information setting unit;
A rigidity information setting unit that sets information on rigidity for the divided element having the overlapping region based on the degree of overlap between the first and second dividing elements having the overlapping region;
An analysis model creation processing unit for creating an analysis model by incorporating information on the set displacement and information on rigidity; and
An analysis model creation device comprising: The second division processing unit divides a designated range at an edge of the entire region into the plurality of second division elements.
The analysis model creation device according to claim 1. The second division processing unit divides the entire peripheral portion of the entire region into the plurality of second division elements.
The analysis model creation device according to claim 1. The displacement information setting unit uses the shape function of the finite element method to calculate the displacement amount of the nodes between the first and second divided elements having overlapping regions when stress is applied to the analysis object. Set
The analysis model creation device according to any one of claims 1 to 3. The rigidity information setting unit sets an elastic modulus for the first divided element having the overlapping region based on the degree of overlap between the first and second dividing elements having the overlapping region.
The analysis model creation device according to any one of claims 1 to 4. The overlapping region is specified by a coordinate system,
The rigidity information setting unit sets a longitudinal elastic modulus and a transverse elastic modulus for the first divided element having the overlapping region based on the coordinate value of the overlapping region between the first and second dividing elements. ,
The analysis model creation device according to any one of claims 1 to 4. A first division processing unit that divides the entire region corresponding to the shape of the analysis object into a plurality of first division elements having a uniform shape;
A second division processing unit that divides an edge portion of the entire region corresponding to the shape of the analysis object into a plurality of second division elements having an arbitrarily defined shape;
Based on the relative positional relationship between the nodes of the first and second divided elements having overlapping regions, information relating to the displacement of the nodes when the stress is applied to the object to be analyzed is set. A displacement information setting unit;
A rigidity information setting unit that sets information on rigidity for the divided element having the overlapping region based on the degree of overlap between the first and second dividing elements having the overlapping region;
An analysis model creation processing unit for creating an analysis model by taking in information on the set displacement and information on rigidity,
An analysis model creation program that allows a computer to function as a computer. Dividing the entire region corresponding to the shape of the analysis object into a plurality of first division elements having a uniform shape;
Dividing an edge of the entire region corresponding to the shape of the analysis object into a plurality of second division elements having an arbitrarily defined shape;
Based on the relative positional relationship between the nodes of the first and second divided elements having overlapping regions, information relating to the displacement of the nodes when the stress is applied to the object to be analyzed is set. Steps,
Based on the degree of overlap between the first and second division elements having the overlapping area, setting information on rigidity for the division element having the overlapping area;
Taking in the information on the set displacement and information on the rigidity to create an analysis model;
An analysis model creation method having

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