A parametric modeling method for finite element model of origami torsion buffer structure

Abstract

The present invention discloses a parametric modeling method of a finite element model of an origami-type torsion buffer structure, which obtains independent design parameters and finite element mesh parameters of the origami-type torsion buffer structure, constructs a parametric modeling node coordinate matrix, a node numbering matrix, and a shell unit node-mesh corresponding matrix of the characteristic structure; performs a circular array on the node coordinate matrix of the characteristic structure to obtain the overall node coordinate matrix of the finite element model, and generates a corresponding node numbering matrix and a shell unit node-mesh corresponding matrix; obtains a node numbering correspondence matrix of a crease position, generates a hinge unit, and finally generates a parametric finite element model of an origami-type torsion buffer structure by coding. The present invention solves the modeling problem of complex spatial creases of an origami-type torsion buffer structure by parameterizing the origami-type torsion buffer structure, has the characteristics of being fast and accurate, is conducive to improving the research and design efficiency of the origami-type buffer structure, and shortens its research and development cycle.

Description

Technical Field

[0001] The invention relates to the field of finite element simulation analysis of an origami torsion buffer structure, and in particular to a parameterized modeling method of a finite element model of an origami torsion buffer structure. Background Art

[0002] Origami is an ancient folding art that transforms a flat sheet of paper into a complex three-dimensional structure by using very complex crease patterns. Origami structures can achieve complex three-dimensional shape transformations and can also exhibit mechanical properties that are difficult to achieve with traditional materials. Therefore, origami structures have opened up new avenues for the research and development of new structures and materials, and have attracted widespread attention in fields including aerospace deployable structures, robots, adaptive civil infrastructure, and nano-intelligent structures.

[0003] However, due to the application of complex crease patterns, the generated three-dimensional origami structure is very complex, with creases crisscrossing in space. The traditional manual finite element simulation modeling method is time-consuming, and the research on the macroscopic kinematics and mechanical properties of origami structures is extremely dependent on the adjustment and optimization design of structural parameters. The repeated modeling requirements double the time cost of the research. Summary of the invention

[0004] Purpose of the invention: The purpose of the present invention is to solve the problem that the modeling of finite element models of origami-type structures in the prior art is time-consuming, and to provide a parametric modeling method for finite element models of origami-type torsion buffer structures.

[0005] Technical solution: A parametric modeling method of a finite element model of an origami-type torsion buffer structure of the present invention comprises the following steps:

[0006] Step 1, obtaining design parameters of the origami torsion buffer structure and parameters of the finite element model;

[0007] The origami torsion buffer structure is formed by connecting two Kresling origami structures in a coaxial manner. The design parameters of the origami torsion buffer structure include the number of edges of the regular polygon n, the radius of the circumscribed circle of the regular polygon R, the initial angle θ of the upper Kesling origami structure, the initial height ratio r of the upper and lower Kresling origami structures. h , the initial height h1 of the upper Kresling origami structure; the mesh type in the finite element model adopts shell elements, and for any triangular panel on the side of the origami structure, the number of meshes on its three sides is m, and the size l of the mesh on the three sides is obtained by the ratio of the length of the three sides on the triangular folding surface to the number of meshes. m1 , l m2 and l m3 ;

[0008] Step 2: Combined with the rotational symmetry characteristics of the origami torsion buffer structure, the characteristic structure is selected and its parametric modeling node coordinate matrix, node number matrix, and shell unit node-grid correspondence matrix are constructed. The specific method is as follows:

[0009] First, for the upper Kresling origami structure, a quadrilateral is formed between each two adjacent peak folds on its side, and the diagonal of the quadrilateral is the valley fold. The valley fold divides the quadrilateral into two triangular folding surfaces, which are recorded as triangle ABB' and triangle AA'B'; take point O as the origin, and obtain the vectors OA, OB, OB' and OA' starting from the origin and reaching the four vertices;

[0010] Then, obtain the unit vectors of the sides of the folding surface triangle ABB' and triangle AA'B' in space, which are recorded as u B'A 、u BA 、u B'B 、u B'A' and u AA' ;

[0011] Secondly, starting from any vertex in triangle ABB', construct its finite element mesh node coordinate matrix. Assume that the node coordinate matrix after meshing triangle ABB' starting from point B' is N ABB' ; Node coordinate matrix N ABB' The corresponding node number matrix is ​​Nn ABB' , the number of non-zero elements in the node number matrix (i.e. the number of nodes) is set to N IDn ; Based on Nn ABB' The shell element node-grid correspondence matrix of triangle ABB' is recorded as E ABB' ; E ABB' Each submatrix in represents a finite element mesh. The submatrix with a 0 element is a triangular mesh, the submatrix without 0 is a quadrilateral mesh, and the rest are not meshed. The 1, 2, 3, 4, ... in the submatrix refers to the node number in the matrix (13);

[0012] Next, use the same method to obtain the node coordinate matrix N of the folding surface triangle AA'B' AA'B' 、The node number matrix Nn of triangle AA'B' AA'B' , the shell element node-mesh correspondence matrix E of triangle AA'B' AA'B' ;

[0013] Finally, the finite element mesh information of the characteristic structure in the Kresling origami structure is obtained ( Figure 3 ), including the node coordinate matrix and the corresponding node number matrix, and the shell element node-mesh correspondence matrix;

[0014] Step 3, perform a circular array on the node coordinate matrix of the characteristic structure, and use a rotation matrix to rotate each coordinate point in the node coordinate matrix n times along the OO' axis, thereby obtaining the node coordinate matrix of the upper Kresling origami structural unit finite element model and the corresponding node number matrix and shell unit node-grid correspondence matrix;

[0015] Repeat steps 1 to 3 to obtain the node coordinate matrix and corresponding node number matrix of the Kresling origami structural unit finite element model, and the shell unit node-grid correspondence matrix;

[0016] Step 4: Generate a node number correspondence matrix of the fold position of the origami torsion buffer structure based on the node number matrix obtained in step 3, which is used for pairing nodes in the hinge unit; for any set of hinge relationships of the fold position of triangle AB B' and triangle AA'B', the calculation method is:

[0017] According to the arrangement of non-zero elements in the node number matrix of triangle AB B' and triangle AA'B', the node pair numbers of the two triangles at the fold position are obtained, and the node number correspondence matrix N is formed. p1 , N p1 The elements in the matrix are the elements on the diagonal of the node number matrix, and each row of elements constitutes a node pair, representing a hinge unit; then, based on the shape and position of the non-zero elements in the node number matrix, the node number correspondence matrix of other folds is obtained, and finally the node number correspondence matrix of all folds of the origami torsion buffer structure is obtained;

[0018] Step 5: Based on the above matrix information, use MATLAB to write code to generate the input of ABAQUS

[0019] The file can generate a parametric finite element model of the origami torsion buffer structure.

[0020] Furthermore, the upper Kresling origami structure and the lower Kresling origami structure in the origami torsion buffer structure

[0021] The top and bottom surfaces of the origami structure are both regular polygons with n sides, a side length of P, and a circumscribed circle radius of R; the side surfaces are n parallelograms;

[0022] The initial height of the upper Kresling origami structure is:

[0023]

[0024] The initial height of the Kresling origami structure is:

[0025] h2=H-h1(2)

[0026] Wherein, H is the initial total height of the origami-type torsion buffer structure.

[0027] Furthermore, in step 2, with point O as the origin, the calculation formulas for obtaining the vectors OA, OB, OB' and OA' starting from the origin and reaching the four vertices are as follows:

[0028] OA=[R,0,0] T (3)

[0029]

[0030] OA'=[Rcosθ,Rsinθ,h1] T (6)

[0031] The calculation formula for the unit vector of the sides of triangle ABB' and triangle AA'B' in space is as follows:

[0032]

[0033] The node coordinate matrix N after triangle ABB' meshing ABB' The expression is:

[0034]

[0035] Node coordinate matrix N ABB' The corresponding node number matrix is ​​Nn ABB'

[0036]

[0037] The number of non-zero elements in the node matrix (i.e. the number of nodes) is:

[0038]

[0039] Based on Nn ABB' , the shell element node-mesh correspondence matrix E of triangle ABB' ABB' The calculation formula is:

[0040] E ABB' Each submatrix in stores a finite element mesh information. When establishing a network, the submatrix containing a 0 element is a triangular mesh, the submatrix without a 0 element is a quadrilateral mesh, and the rest are not meshed. The 1, 2, 3, 4, ... in the submatrix refers to the node number in the matrix (13);

[0041] Next, use the same calculation method to obtain the node coordinate matrix N of triangle AA'B' AA'B' , the calculation formula is:

[0042]

[0043] The node number matrix Nn of triangle AA'B' AA'B' for:

[0044]

[0045] Shell element node-mesh correspondence matrix E of triangle AA'B' AA'B' for:

[0046]

[0047] Repeat the above method to obtain the characteristic structure of the Kresling origami structure, including the node coordinate matrix and the corresponding node number matrix, and the shell element node-grid correspondence matrix;

[0048] Finally, the node coordinate matrix of the characteristic structure of the upper and lower Kresling origami structures and the corresponding node number matrix and shell unit node-grid correspondence matrix are obtained.

[0049] Furthermore, the expression of the rotation matrix in step 3 is as follows:

[0050]

[0051] Where θ = 2π / n; the number of times the array is rotated is the number of polygon edges n;

[0052] All the bold elements in the above matrices (such as in matrices 7-12) are space vectors, that is, each element has three values ​​xyz (in mathematics, bold letters are usually used to represent vectors); the node coordinate information of matrices (12) and (16) and other characteristic structures are substituted into the rotation matrix in turn, and finally the node coordinate matrix of the upper and lower Kresling origami structure unit finite element models and the corresponding node number matrix and shell unit node-grid correspondence matrix are obtained.

[0053] Furthermore, the node number correspondence matrix N of the articulated units at the folding positions of triangles AB B' and AA'B' in step 4 is p1 The specific expression is:

[0054]

[0055] Among them, the first column corresponds to the node number matrix Nn ABB' , which is the node number of triangle AB B'; the second column corresponds to the node number matrix Nn AA'B' , which is the node number of triangle AA'B'. Matrix N p1 Each line in is the node pair required to form a hinge unit;

[0056] Repeat the above steps to finally obtain the node number correspondence matrix of the hinge units at all folds of the origami torsion buffer structure.

[0057] Furthermore, in step five, the MATLAB programming development tool is used to write the node number information, node coordinate information and shell unit node-grid correspondence information of the origami torsion buffer structure finite element model according to the writing rules of the ABAQUS inp file to generate a finite element mesh model. Then, the folding surfaces are hinged based on the node number correspondence matrix of the hinge. Further write the folding surface material information, shell unit attribute information, hinge attribute information, load and boundary condition information, write the display dynamics analysis step information and field variable / historical variable output information, and after completing the inp file writing, it can be directly submitted to the ABAQUS / Explicit solver for calculation.

[0058] Beneficial effects: The finite element model obtained by the technical solution of the present invention simulates the warping and deformation of the triangular panel through the shell unit, and simulates the folding deformation at the crease through the hinge unit. The finite element model can accurately simulate the torsional deformation process of the origami torsion buffer structure as a whole during loading, and the reaction force generated by it. The parametric modeling method of the present invention can realize the automatic modeling of the origami torsion buffer structure, greatly improve the modeling efficiency, and is of great significance for improving the efficiency of structural optimization design and shortening the research and development cycle. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] Figure 1 It is a schematic diagram of the overall process of the present invention;

[0060] Figure 2 Schematic diagram of the characteristic structure of the Kresling origami structure in the embodiment;

[0061] Figure 3 Schematic diagram of determination of node coordinates and coding rules in triangle ABB' in the embodiment;

[0062] Figure 4 A schematic diagram of generating a circular array grid of a characteristic structure of a torsion buffer structure in an embodiment;

[0063] Figure 5 Schematic diagram of node pairing in hinge connection in the embodiment;

[0064] Figure 6 This is a schematic diagram of an origami-type torsion buffer structure in an embodiment;

[0065] Figure 7 Schematic diagram of the finite element model of the torsion buffer structure with different n values ​​in the embodiment. DETAILED DESCRIPTION

[0066] The technical solution of the present invention is described in detail below, but the protection scope of the present invention is not limited to the embodiments.

[0067] like Figure 1 As shown, a modeling method of a parametric finite element model of an origami-type torsion buffer structure of the present invention comprises the following steps:

[0068] Step 1, obtaining design parameters of the origami torsion buffer structure and parameters of the finite element model;

[0069] The origami torsion buffer structure is formed by connecting two Kresling origami structures in a coaxial manner. The design parameters of the origami torsion buffer structure include the number of edges of the regular polygon n, the radius of the circumscribed circle of the regular polygon R, the initial angle θ of the upper Kesling origami structure, the initial height ratio r of the upper and lower Kresling origami structures. h , the initial height h1 of the upper Kresling origami structure; the mesh type in the finite element model adopts shell elements, and for any triangular panel on the side of the origami structure, the number of meshes on its three sides is m, and the size l of the mesh on the three sides is obtained by the ratio of the length of the three sides on the triangular folding surface to the number of meshes. m1 , l m2 and l m3 ;

[0070] The independent design parameters and finite element model parameters of the origami-type torsion buffer structure are filled in the beginning of the MATLAB program.

[0071] Step 2: Combined with the rotational symmetry characteristics of the origami torsion buffer structure, the characteristic structure is selected and its parametric modeling node coordinate matrix, node number matrix, and shell unit node-grid correspondence matrix are constructed. The specific method is as follows:

[0072] First, for the upper Kresling origami structure, a quadrilateral is formed between each two adjacent peak folds on its side (a parallelogram after the plane is unfolded), and the diagonal of the quadrilateral is the valley fold. The valley fold divides the quadrilateral into two triangular folded surfaces, denoted as triangle ABB' and triangle AA'B'; take point O as the origin, and obtain the vectors OA, OB, OB' and OA' starting from the origin and reaching the four vertices, as follows: Figure 2 As shown;

[0073] Then, obtain the unit vectors of the sides of the folding surface triangle ABB' and triangle AA'B' in space and record them as u B'A 、u BA 、u B'B 、u B'A' and u AA' ;

[0074] Secondly, starting from any vertex in triangle ABB', construct its finite element mesh node coordinate matrix. Assume that starting from point B' (such as Figure 3 (a) shows that the node coordinate matrix after the triangle ABB' is meshed is N ABB' ; Node coordinate matrix N ABB' The corresponding node number matrix is ​​Nn ABB' , the number of non-zero elements in the node number matrix (i.e. the number of nodes) is set to N IDn ; Based on Nn ABB' The shell element node-grid correspondence matrix of triangle ABB' is recorded as E ABB' ; E ABB' Each submatrix in represents a finite element mesh. The submatrix with a 0 element is a triangular mesh, the submatrix without 0 is a quadrilateral mesh, and the rest are not meshed. The 1, 2, 3, 4, etc. in the submatrix refer to the node numbers in the matrix (13), such as Figure 3 As shown in (b);

[0075] Next, use the same method to obtain the node coordinate matrix N of the folded surface triangle AA'B' AA'B' 、The node number matrix Nn of triangle AA'B' AA'B' , the shell element node-mesh correspondence matrix E of triangle AA'B' AA'B' ; Here, the shape characteristics of the non-zero elements in the node coordinate matrix of triangle ABB' are consistent with the shape characteristics of triangle ABB' in space; Figure 6 As shown, the torsion buffer structure is a circularly symmetrical structure, which is obtained by first establishing a characteristic structure and then performing a circular array. Triangle ABB' and triangle AA'B' are characteristic structures of the extracted upper Kresling origami structure. After obtaining the matrix information of the two triangles, it is only necessary to perform a circular array on the coordinate matrix to obtain the corresponding coordinate matrix of other parts of the structure, and finally obtain the node coordinate matrix of the entire upper Kresling origami structure. This idea is close to the idea of ​​three-dimensional modeling. For example, to establish a five-pointed star model, it is only necessary to first establish one of the corners, and then rotate the array along the central axis to obtain the five-pointed star model.

[0076] Finally, the same method as above is used to obtain the node coordinate matrix of the characteristic structure of the Kresling origami structure and the corresponding node number matrix and shell unit node-mesh correspondence matrix.

[0077] Step 3: Circular array the node coordinate matrix of the characteristic structure, and use the rotation matrix to rotate each coordinate point in the node coordinate matrix along the OO' axis (such as Figure 2) is rotated n times, thereby obtaining the node coordinate matrix and the corresponding node number matrix of the upper Kresling origami structural unit finite element model, and the shell unit node-grid correspondence matrix;

[0078] Repeat steps 1 to 3 to obtain the node coordinate matrix and corresponding node number matrix of the Kresling origami structural unit finite element model, and the shell unit node-mesh correspondence matrix.

[0079] Step 4: Generate a node number correspondence matrix at the fold of the origami-type torsion buffer structure based on the node number matrix obtained in step 3; take the hinge relationship between triangle AB B' and triangle AA'B' as an example, Figure 5 As shown, according to the arrangement of non-zero elements in the node number matrix of triangle AB B' and triangle AA'B', the node number N of the hinge unit of the two triangles at the fold position is obtained. p1 , N p1 The elements in the node number matrix are the elements on the diagonal of the node number matrix, and each row of elements constitutes a node pair, representing a hinge unit; then, based on the shape and position of the non-zero elements in the node number matrix, the node number correspondence matrix of other folds is obtained, and finally the node number correspondence matrix of all folds of the origami torsion buffer structure is obtained; Figure 5 (a) is a schematic diagram of the structure before articulation. Figure 5 (b) in the figure is the effect picture after the hinge is completed.

[0080] Step 5: Based on the above matrix information, use MATLAB to write code to generate the input of ABAQUS

[0081] The file can generate a parametric finite element model of the origami torsion buffer structure.

[0082] The top and bottom surfaces of the upper Kresling origami structure and the lower Kresling origami structure in the origami-type torsion buffer structure of this embodiment are both regular polygons, with n sides, a side length of P, and a circumscribed circle radius of R; the side surfaces are n parallelograms (before compression and torsion);

[0083] The initial height of the upper Kresling origami structure is:

[0084]

[0085] The initial height of the Kresling origami structure is:

[0086] h2=H-h1(2)

[0087] Wherein, H is the initial total height of the origami-type torsion buffer structure.

[0088] Furthermore, in step 2, point O is taken as the origin, and vectors ( Figure 2 ) The calculation formulas for OA, OB, OB' and OA' are as follows:

[0089] OA=this[R,0,0] T (3)

[0090]

[0091] OA'=[Rcosθ,Rsinθ,h1] T (6)

[0092] The calculation formula for the unit vector of the sides of triangle ABB' and triangle AA'B' in space is as follows:

[0093]

[0094] The node coordinate matrix N after triangle ABB' meshing ABB' The expression is:

[0095]

[0096] Node coordinate matrix N ABB' The corresponding node number matrix is ​​Nn ABB'

[0097]

[0098] The number of non-zero elements in the node matrix (i.e. the number of nodes) is:

[0099]

[0100] Based on Nn ABB' , the shell element node-mesh correspondence matrix E of triangle ABB' ABB' The calculation formula is:

[0101]

[0102] E ABB' Each submatrix in stores a finite element mesh information. When creating a mesh, the submatrix with a 0 element is a triangular mesh, the submatrix without a 0 element is a quadrilateral mesh, and the rest are not meshed. The 1, 2, 3, 4, etc. in the submatrix point to the matrix Nn. ABB' The node number in ;

[0103] Next, use the same calculation method to obtain the node coordinate matrix N of triangle AA'B' AA'B' , the calculation formula is:

[0104]

[0105] The node number matrix Nn of triangle AA'B' AA'B' for:

[0106]

[0107] Shell element node-mesh correspondence matrix E of triangle AA'B' AA'B' for:

[0108]

[0109] Repeating the above method can obtain the characteristic structure of the lower Kresling origami structure and its corresponding upper and lower panels, including the node coordinate matrix and the corresponding node number matrix, and the shell unit node-grid correspondence matrix.

[0110] Finally, the node coordinate matrix of the characteristic structure of the upper and lower Kresling origami structures and their corresponding upper and lower panels, the corresponding node number matrix, and the shell unit node-grid correspondence matrix are obtained.

[0111] In this embodiment, all bold elements in the matrix are space vectors, that is, each element has three values ​​of x, y, and z.

[0112] Furthermore, the expression of the rotation matrix in step 3 is as follows:

[0113]

[0114] Where θ = 2π / n; the number of times the array is rotated is the number of polygon edges n;

[0115] Substitute the node coordinate information in matrices (12) and (16) and the node coordinate matrices of other characteristic structures into the rotation matrix in turn, and finally obtain the node coordinate matrices of the upper and lower Kresling origami structural unit finite element models and the corresponding node number matrix and shell unit node-grid correspondence matrix.

[0116] Furthermore, in step 4, the node number N of the articulated unit between triangle AB B' and triangle AA'B' is p1 The specific expression is:

[0117]

[0118] The first column corresponds to the node number matrix (13), that is, the node number of triangle AB B'; the second column corresponds to the node number matrix (17), that is, the node number of triangle AA'B'. Each row in the matrix (20) is the node pair required to form a hinge unit;

[0119] Repeat the above steps to finally obtain the node number correspondence matrix of the hinge position of the origami torsion buffer structure.

[0120] Furthermore, step 5 is programmed using MATLAB, and the node number information, node coordinate information and shell unit node-mesh correspondence information of the origami torsion buffer structure finite element model are written according to the writing rules of the ABAQUS inp file to generate a finite element mesh model; then, based on the node number correspondence matrix of the hinge, the Hinge unit is used to hinge each folding surface and then the folding surface material information, shell unit attribute information, hinge attribute information, load and boundary condition information are written, and the display dynamics analysis step information and field variable / historical variable output information are written. After completing the writing of the inp file, it can be directly submitted to the ABAQUS / Explicit solver for calculation.

[0121] The present invention adopts a parametric automatic modeling method, and the single modeling time is less than ten seconds, which greatly improves the modeling efficiency, thereby improving the design and optimization efficiency. The origami-type torsion buffer structure obtained by the modeling method of the present invention can be used in the joints of industrial robots, and when the robot arm encounters an obstacle or injures a worker, it can buffer and absorb energy through its own torsion deformation.

[0122] In this embodiment, the characteristic structures of the two folding triangles of the upper Kresling origami structure are first obtained, such as Figure 2 As shown; starting from point B', we get the node coordinates of triangle ABB' ( Figure 3 (a) and its encoding ( Figure 3 (b) in the figure, and then obtain the node coordinate matrix and corresponding node number matrix of the characteristic structure of the upper and lower Kresling origami structures, the shell unit node-grid correspondence matrix and perform circular array, such as Figure 4 As shown; for any set of triangles AB B' and AA'B', the hinge relationship between the two is established using Hinge units as shown Figure 5 As shown, first get the node number of the hinge unit between triangle AB B' and triangle AA'B' as Figure 5 (a) in the figure, and then hinge it as Figure 5 (b) in .

[0123] The geometric structure of the origami-type torsion buffer structure finally obtained in this embodiment is as follows Figure 6 , and further, different n values ​​can be set according to actual needs to establish origami-type torsion buffer structure finite element models with different n values, such as Figure 7 shown.

Claims

1. A parametric modeling method for a finite element model of an origami-type torsion buffer structure, characterized in that: The following steps are involved: Step 1, obtaining design parameters of the origami torsion buffer structure and parameters of the finite element model; The origami torsion buffer structure is formed by connecting two Kresling origami structures in a coaxial manner. The design parameters of the origami torsion buffer structure include the number of edges of the regular polygon n, the radius of the circumscribed circle of the regular polygon R, the initial angle θ of the upper Kesling origami structure, the initial height ratio r of the upper and lower Kresling origami structures. h , the initial height h1 of the upper Kresling origami structure; the mesh type in the finite element model adopts shell elements, and for any triangular panel on the side of the origami structure, the number of meshes on its three sides is m, and the size l of the mesh on the three sides is obtained by the ratio of the length of the three sides on the triangular folding surface to the number of meshes. m1 , l m2 and l m3 ; Step 2: Combined with the rotational symmetry characteristics of the origami torsion buffer structure, the characteristic structure is selected and its parametric modeling node coordinate matrix, node number matrix, and shell unit node-grid correspondence matrix are constructed. The specific method is as follows: First, for the upper Kresling origami structure, a quadrilateral is formed between each two adjacent peak folds on its side, and the diagonal of the quadrilateral is the valley fold. The valley fold divides the quadrilateral into two triangular folding surfaces, which are recorded as triangle ABB' and triangle AA'B'; take point O as the origin, and obtain the vectors OA, OB, OB' and OA' starting from the origin and reaching the four vertices; Then, obtain the unit vectors of the sides of the folding surface triangle ABB' and triangle AA'B' in space, which are denoted as u B'A 、u BA 、u B'B 、u B'A' and u AA' ; Secondly, starting from any vertex in triangle ABB', construct its finite element mesh node coordinate matrix. Assume that the node coordinate matrix after meshing triangle ABB' starting from point B' is N ABB' ; Node coordinate matrix N ABB' The corresponding node number matrix is ​​Nn ABB' , the number of non-zero elements in the node number matrix is ​​set to N IDn , then based on Nn ABB' The shell element node-grid correspondence matrix of triangle ABB' is recorded as E ABB' ; E ABB' Each submatrix in represents a finite element mesh. The submatrix with a 0 element is a triangular mesh, the submatrix without 0 is a quadrilateral mesh, and the rest are not meshed. The non-zero elements in the submatrix refer to the matrix Nn ABB' The node number in ; Next, use the same method to obtain the node coordinate matrix N of the folded surface triangle AA'B' AA'B' 、The node number matrix Nn of triangle AA'B' AA'B' , the shell element node-mesh correspondence matrix E of triangle AA'B' AA'B' ; Finally, the finite element mesh information of the characteristic structure in the upper Kresling origami structure is obtained, including the node coordinate matrix and the corresponding node number matrix, and the shell element node-mesh correspondence matrix; Step 3, perform a circular array on the node coordinate matrix of the characteristic structure, and use a rotation matrix to rotate each coordinate point in the node coordinate matrix n times along the OO' axis, thereby obtaining the node coordinate matrix of the upper Kresling origami structural unit finite element model and the corresponding node number matrix and shell unit node-grid correspondence matrix; Repeat steps 1 to 3 to obtain the node coordinate matrix and corresponding node number matrix of the Kresling origami structural unit finite element model, and the shell unit node-grid correspondence matrix; Step 4: Based on the node number matrix obtained in step 3, a node number correspondence matrix of the fold position of the origami torsion buffer structure is generated for pairing the nodes in the hinge unit. For any set of the hinge relationship between triangle AB B' and triangle AA'B', the calculation method is as follows: According to the arrangement of non-zero elements in the node number matrix of triangle AB B' and triangle AA'B', the node pair numbers of the two triangles at the fold position are obtained, and the node number correspondence matrix N is formed. p1 , N p1 The elements in the matrix are the elements on the diagonal of the node number matrix, and each row of elements constitutes a node pair, representing a hinge unit; then, based on the shape and position of the non-zero elements in the node number matrix, the node number correspondence matrix of other folds is obtained, and finally the node number correspondence matrix of all folds of the origami torsion buffer structure is obtained; Step 5: Based on the above matrix information, MATLAB is used to write code to generate an inp file for ABAQUS, thereby generating a parametric finite element model of the origami torsion buffer structure.

2. The parametric modeling method of the finite element model of the origami torsion buffer structure according to claim 1 is characterized in that: The top and bottom surfaces of the upper Kresling origami structure and the lower Kresling origami structure in the origami torsion buffer structure are both regular n-gons, with a side length of P and a circumscribed circle radius of R; the side surfaces are n parallelograms; The initial height of the upper Kresling origami structure is: The initial height of the Kresling origami structure is: h2=H-h1(2) where H is the initial total height of the origami-type torsion buffer structure.

3. The parametric modeling method of the finite element model of the origami torsion buffer structure according to claim 1 is characterized in that: In step 2, the calculation formulas for obtaining the vectors OA, OB, OB' and OA' starting from the origin and reaching the four vertices are as follows: OA=[R,0,0] T (3) OA'=[Rcosθ,Rsinθ,h1] T (6) The calculation formula for the unit vector of the sides of triangle ABB' and triangle AA'B' in space is as follows: The node coordinate matrix N after triangle ABB' meshing ABB' The expression is: U OB' It refers to the unit vector in the OB' direction, and its calculation formula is: Node coordinate matrix N ABB' The corresponding node number matrix is ​​Nn ABB' The number of non-zero elements in the node matrix is: Based on Nn ABB' , the shell element node-mesh correspondence matrix E of triangle ABB' ABB' The calculation formula is: E ABB' Each submatrix in the matrix stores a finite element mesh information. When creating a mesh, the submatrix containing a 0 element is a triangular mesh, the submatrix without a 0 element is a quadrilateral mesh, and the rest are not divided into meshes. The non-zero elements in the submatrix refer to the matrix Nn ABB' The node number in ; Next, use the same calculation method to obtain the node coordinate matrix N of triangle AA'B' AA'B' , the calculation formula is: The node number matrix Nn of triangle AA'B' AB'B' for: Shell element node-mesh correspondence matrix E of triangle AA'B' AA'B' for: Repeat the above method to obtain the characteristic structure of the Kresling origami structure, including the node coordinate matrix and the corresponding node number matrix, and the shell element node-grid correspondence matrix; Finally, the characteristic structures of the upper and lower Kresling origami structures are obtained, including the node coordinate matrix and the corresponding node number matrix, and the shell unit node-mesh correspondence matrix.

4. The parametric modeling method of the finite element model of the origami torsion buffer structure according to claim 3 is characterized in that: The expression of the rotation matrix in step 3 is as follows: Where θ = 2π / n; the number of times the array is rotated is the number of polygon edges n; Substitute the node coordinate information in matrices (12) and (16) into the rotation matrix in turn, and finally obtain the node coordinate matrix of the upper and lower Kresling origami structural unit finite element models and the corresponding node number matrix and shell unit node-grid correspondence matrix.

5. The parametric modeling method of the finite element model of the origami torsion buffer structure according to claim 1 is characterized in that: The node number correspondence matrix N of the articulated units of triangle AB B' and triangle AA'B' at the crease position in step 4 p1 The specific expression is: Among them, the first column corresponds to the node number matrix Nn ABB' , which is the node number of triangle ABB'; the second column corresponds to the node number matrix Nn AA'B' , that is, the node number of triangle AA'B'; matrix N p1 Each line in is the node pair required to form a hinge unit; Repeat the above steps to finally obtain the node number correspondence matrix of the hinge units at all folds of the origami torsion buffer structure.

6. The parametric modeling method of the origami torsion buffer structure finite element model according to claim 1 is characterized in that: The step 5 is developed by programming with MATLAB, and the node number information, node coordinate information and shell unit node-grid correspondence information of the origami torsion buffer structure finite element model are written according to the writing rules of ABAQUS inp file to generate a finite element mesh model; Then, each folding surface is hinged based on the node number correspondence matrix of the hinge, and the folding surface material information, shell unit property information, hinge property information, load and boundary condition information are written again. The display dynamic analysis step information and field variable / historical variable output information are written. After completing the inp file writing, it can be directly submitted to the ABAQUS / Explicit solver for calculation.

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