Design method of heterogeneous energy absorption structure of three-period minimal curved surface structure

Abstract

A heterogeneous energy absorption structure design method of a three-period minimal curved surface structure is characterized in that a stretching-dominated P structure with layer-by-layer fracture deformation as a main part and a bending-dominated W structure with 45-degree diagonal shear fracture deformation as a main part are taken as objects, and the strength of fracture deformation areas of an original P structure and an original W structure is enhanced in a manner of mutual fusion of the P structure and the W structure; therefore, the energy absorption capability of the designed structure is improved. The method comprises the following steps: firstly, establishing corresponding P and W structure geometric models on the basis of P and W three-period minimal surface functions; then, heterogeneous structure filling areas of P and W structures are divided, the type of a filling structure is determined, and heterogeneous fusion boundary position functions of a heterogeneous MP structure and a heterogeneous MW structure are established respectively; and finally, on the basis of the heterogeneous fusion boundary position function of the MP structure and the MW structure, constructing implicit surface functions of the MP structure and the MW structure, and generating geometric models of the MP structure and the MW structure.

Description

Technical Field

[0001] The present invention belongs to the technical field of computer-aided structural design, and particularly relates to a design method for a heterogeneous energy-absorbing structure with a triply periodic minimal surface structure. Background Art

[0002] Lattice porous structures have natural characteristics such as light weight and high strength, and thus are widely used in energy absorption and impact resistance design in fields such as aerospace, vehicle engineering, and medicine. Traditional lattice porous materials, such as foam materials and honeycomb materials, are limited by manufacturing capabilities and cannot fabricate complex microstructures or arbitrarily adjust internal structure parameters. Therefore, the energy absorption capacity of traditional porous buffer materials is very limited. With the development of computer-aided design and additive manufacturing technologies, the design of complex microstructures has become possible. Lattice porous structures such as truss structures, implicit surface structures, and topological structures have been widely used in energy absorption and impact resistance design in various industries.

[0003] Currently, although various types of lattice porous structures invented and designed provide a large number of designable cell structure libraries for the customized energy-absorbing structure design of relevant designers, there are still some deficiencies in the means of energy absorption design. The design of the energy absorption capacity of lattice porous structures still depends on the design of the structural parameters of the internal cell structure and the gradient design of the overall internal cell structure, and there is still room for further improvement in the energy absorption capacity of heterogeneous energy-absorbing structures based on lattice porous structures. At the same time, different types of lattice porous structures exhibit different advantages in energy absorption capacity, and there is an urgent need for a heterogeneous structure design method that integrates the superior energy absorption capabilities of different types of lattice porous structures. Summary of the Invention

[0004] In view of the deficiencies of the prior art, the present invention provides a design method for a heterogeneous energy absorption structure with a three-period minimal surface structure, specifically a design method for a heterogeneous energy absorption structure in which a three-period minimal surface Primitive and an iWp structure are mutually integrated; this method takes the tensile-dominated Primitive (P) structure mainly featuring layer-by-layer fracture deformation and the bending-dominated iWp (W) structure mainly featuring 45° diagonal shear fracture deformation as objects, and enhances the strength of the fracture deformation regions of the original P structure and the original W structure by integrating the P structure and the W structure, so as to improve the energy absorption capacity of the designed structure. First, based on the three-period minimal surface functions of P and W respectively, corresponding geometric models of the P and W structures are established; then, the heterogeneous structure filling regions of the P and W structures are divided, the types of filling structures are determined, and the position functions of the heterogeneous fusion boundaries of the heterogeneous P (Multi-Primitive, MP) structure and the heterogeneous W (Multi-iWp, MW) structure are established respectively; finally, based on the position functions of the heterogeneous fusion boundaries of the MP structure and the MW structure, implicit surface functions of the MP structure and the MW structure are constructed, and geometric models of the MP structure and the MW structure are generated.

[0005] A design method for a heterogeneous energy absorption structure in which a three-period minimal surface Primitive and an iWp structure are mutually integrated, comprising the following steps:

[0006] S1: Generate a geometric model of a lattice porous P structure according to the three-period minimal surface P function, and generate a geometric model of a lattice porous W structure according to the three-period minimal surface W function;

[0007] S2: Divide and determine the position, width and type of the heterogeneous filling structure (W structure) of the vertical heterogeneous filling design region of the P structure, and divide and determine the position, width and type of the heterogeneous filling structure (P structure) of the 45° diagonal heterogeneous filling design region of the W structure;

[0008] S3: Determine the geometric boundary of the heterogeneous structure fusion according to the heterogeneous filling regions of the P structure and the W structure, and establish the heterogeneous structure fusion boundary function of 1 / 4 of the MP structure and 1 / 4 of the MW structure;

[0009] S4: Construct implicit functions of 1 / 4 of the MP structure and 1 / 4 of the MW structure according to the heterogeneous structure fusion boundary function of 1 / 4 of the MP structure and 1 / 4 of the MW structure;

[0010] S5: Generate geometric models of 1 / 4 of the MP structure and 1 / 4 of the MW structure according to the implicit functions of 1 / 4 of the MP structure and 1 / 4 of the MW structure. With the help of modeling software such as Magics, operations such as replication, mirroring and Boolean union are carried out to generate complete cubic MP structures and MW structures.

[0011] To optimize the above technical solution, the specific measures also include:

[0012] Further, in step S1, the three-period minimal surface P function and W function are:

[0013]

[0014]

[0015] In the formula, x, y, and z are the coordinate values in the three-dimensional Cartesian coordinate system; t is the offset parameter of the surface function; L is the side length of the cell structure. By changing the value of the parameter t in the above formula, a geometric model of the cell structure with different volume fractions (the proportion of the solid in the cell structure) can be generated.

[0016] Further, in step S2, the heterogeneous filling design regions of the P structure and the W structure are respectively:

[0017] Taking the front surface of the cubic envelope contour of the P structure as a reference, the heterogeneous filling design region in the front surface extends along the center line to both sides and is symmetrically distributed. In the left half region of the front surface, from left to right, the design ratio between the P structure filling design region and the W structure heterogeneous filling design region is greater than or equal to 1 / 2 and less than 1; taking the front surface of the cubic envelope contour of the W structure as a reference, the heterogeneous filling design region in the front surface is distributed along the 45-degree diagonal and extends and distributes perpendicular to the diagonal to both sides. The design ratio between the W structure filling design region and the P structure heterogeneous filling design region distributed along the diagonal length in the front surface is greater than or equal to 1 / 2 and less than 1.

[0018] Further, in step S3, the heterogeneous structure fusion boundary functions of 1 / 4 of the MP structure and 1 / 4 of the MW structure are:

[0019] The vertical heterogeneous structure fusion region fusion boundary function of 1 / 4 of the MP structure is:

[0020]

[0021] In the formula, x, y, and z are the coordinate values in the three-dimensional Cartesian coordinate system; l P is the cell size of the P structure.

[0022] The two fusion boundary functions of the 45-degree diagonal heterogeneous structure fusion region of 1 / 4 of the MW structure are:

[0023]

[0024] In the formula, x, y, and z are the coordinate values in the three-dimensional Cartesian coordinate system; l W is the width of the heterogeneous structure filling region; n is the serial number of the fusion boundary function.

[0025] Furthermore, in step S4, the implicit functions of 1 / 4 of the MP structure and 1 / 4 of the MW are as follows:

[0026] The implicit function F(MP) of 1 / 4 of the MP structure is:

[0027]

[0028] F(MP) = α MP ×F(P) + (1 - α MP )×F(W)

[0029] In the formula, α MP is a weight function constructed based on the heterogeneous structure fusion boundary function G MP in step S3.

[0030] The implicit function F(MW) of 1 / 4 of the MW structure is:

[0031]

[0032]

[0033] In the formula, is a weight function constructed based on the heterogeneous fusion boundary function in step S3.

[0034] Furthermore, in step S5, by using modeling software such as Magics, copying and mirroring operations are performed on 1 / 4 of the MP structure and 1 / 4 of the MW structure, and then 4 pieces of 1 / 4 of the MP structure and 4 pieces of 1 / 4 of the MW structure can be obtained; then, through Boolean union operations, the geometric models of the complete cubic MP structure and cubic MW structure can be obtained.

[0035] Compared with the prior art, the beneficial effects of the present invention are as follows: The heterogeneous fusion design of the MP structure effectively improves the sustainable load-bearing capacity of the tensile-dominated P structure. In the platform stress stage, it can exhibit stable energy absorption capacity, greatly improving the energy absorption efficiency of the original P structure and maintaining the high energy absorption magnitude of the original P structure; the heterogeneous fusion design of the MW structure effectively improves the compressive strength of the bending-dominated W structure, greatly increasing the maximum energy absorption of the original W structure and maintaining the high energy absorption efficiency of the original W structure; the mutual fusion design of the tensile-dominated structure and the bending-dominated structure based on the enhanced fracture deformation region provides an effective method for the energy absorption optimization design of single-type lattice porous materials, expanding the application of customized energy absorption design. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1It is a schematic diagram of the geometric models of the three - period minimal surface P structure and W structure of the present invention;

[0037] Figure 2 It is a schematic diagram of the heterogeneous filling regions of the P structure and W structure of the present invention;

[0038] Figure 3 It is a schematic diagram of the geometric models of the 1 / 4 MP structure and the complete MP structure of the present invention;

[0039] Figure 4 It is a schematic diagram of the geometric models of the 1 / 4 MW structure and the complete MW structure of the present invention; Detailed implementation manners

[0040] The technical solution of the present invention will be described in detail below with reference to the accompanying drawings.

[0041] The present invention discloses a design method for a heterogeneous energy - absorbing structure in which a three - period minimal surface Primitive and an iWp structure are mutually fused, including: First, based on the three - period minimal surface P and W functions, geometric models of the P structure and W structure are constructed, and combined with the fracture - deformation enhancement methods of the P structure and W structure, the positions, widths and filling structure types of the heterogeneous structure filling regions are divided; Then, according to the heterogeneous structure fusion boundary positions of the 1 / 4 P structure and the 1 / 4 W structure, a heterogeneous structure fusion boundary function and a geometric modeling implicit function of the 1 / 4 MP structure and the 1 / 4 MW structure are constructed; Finally, geometric models of the 1 / 4 MP structure and the 1 / 4 MW structure are generated, and by borrowing modeling software such as Magics, operations such as replication, mirroring and Boolean union are used to generate complete cubic MP and cubic MW structures.

[0042] Step 1, according to the three - period minimal surface function F(P) of the P structure, in a design space of 120×120×120 mm 3 a cubic P structure is generated, the cell size l1 = 20 mm, and the volume - fraction control parameter t=-1.8, as shown in the geometric model of the P structure Figure 1 in. According to the three - period minimal surface function F(W) of the W structure, in a design space of 120×120×120 mm 3 a cubic W structure is constructed, the cell size l2 = 20 mm, and the volume - fraction control parameter t'=-1.0, as shown in the geometric model of the W structure Figure 1 in. All the dimensions and parameters in this step are only an embodiment and should not be regarded as a limitation to the present invention.

[0043]

[0044]

[0045] Step 2, The P structure is a type of stretch-dominated structure. A W structure with strong continuous load-bearing capacity is filled in the vertical direction in the middle of the structure to improve the energy absorption efficiency of the P structure. The ratio of the filled area of the P structure to the heterogeneous filling area of the W structure is l3:l4 = 2:1, as shown in Figure 2 the heterogeneous filling area of the P structure shown. The W structure is a type of bend-dominated structure. A P structure with high structural strength is filled in the 45-degree diagonal direction of the structure to increase the amount of energy absorbed by the W structure. The ratio of the filled area of the W structure to the heterogeneous filling area of the P structure is l5:l6 = 2:1, as shown in Figure 2 the heterogeneous filling area of the W structure shown. The filling area ratio of this step is only an embodiment and should not be regarded as a limitation to the present invention.

[0046] Step 3, According to the position of the 1 / 4 geometric model of the P structure in the three-dimensional Cartesian coordinate system, based on the ratio of the filled area of the P structure to the heterogeneous filling area of the W structure, determine the MP structure heterogeneous fusion boundary function G(x, y, z), as shown in Figure 3 the 1 / 4 of the MP structure shown.

[0047] G(x, y, z) = x + 10

[0048] According to the position of the 1 / 4 geometric model of the W structure in the three-dimensional Cartesian coordinate system, based on the ratio of the filled area of the W structure to the filled area of the P structure, determine the MW structure heterogeneous fusion boundary functions G1(x, y, z) and G2(x, y, z), as shown in Figure 3 the 1 / 4 of the MW structure shown.

[0049]

[0050] Step 4, According to the heterogeneous structure fusion boundary function G and the weight function α of the MP structure MP , determine the implicit function F(MP) of the 1 / 4 heterogeneous MP structure. The cell size of the W structure filled in the heterogeneous filling area of the MP structure is l4 = 20 mm, and the volume fraction control parameter t' = -1.0, as shown in Figure 3 the 1 / 4 of the MP structure shown.

[0051]

[0052] F(MP) = α MP ×F(P) + (1 - α MP )×F(W)

[0053] According to the heterogeneous structure fusion boundary functions G1(x, y, z), G2(x, y, z) and the weight function of the MW structure Determine the implicit function F(MW) of the 1 / 4MW structure. The size of the P structure cell filled in the heterogeneous filling area of the MW structure is l6 = 20 mm, and the volume fraction control parameter t' = -1.8, as Figure 4 shown in the 1 / 4 of the MW structure.

[0054]

[0055]

[0056] The size of the structure filling cell and the volume fraction control parameter in the heterogeneous filling area of this step are only one embodiment and should not be regarded as a limitation to the present invention.

[0057] Step 5: Using the magics modeling software, based on the 1 / 4 MP geometric model and the 1 / 4 MW geometric model, perform operations such as replication and mirroring to construct four divided cubic geometric models, and through Boolean union operation, generate the complete cubic MP and cubic MW geometric models, as Figure 3 and Figure 4 shown in the geometric models of the cubic MP structure and the cubic MW structure.

[0058] The above is only the preferred implementation manner of the present invention. The protection scope of the present invention is not limited to the above embodiments. All technical solutions within the idea of the present invention belong to the protection scope of the present invention. It should be noted that for those of ordinary skill in the art, several improvements and retouches made without departing from the principle of the present invention should be regarded as within the protection scope of the present invention.

Claims

1. A design method for a heterogeneous energy absorption structure with a three - period minimal surface structure, characterized in that It includes the following steps: S1: Generate the geometric model of the lattice porous P structure according to the triple-periodic minimal surface P function, and generate the geometric model of the lattice porous W structure according to the triple-periodic minimal surface W function; S2: Divide and determine the position, width, and the type of the heterogeneous filling structure as the W structure of the vertical heterogeneous filling design region of the P structure, and divide and determine the position, width, and the type of the heterogeneous filling structure as the P structure of the 45° diagonal heterogeneous filling design region of the W structure; S3: Determine the geometric boundary of the heterogeneous structure fusion according to the heterogeneous filling regions of the P structure and the W structure, and establish the heterogeneous structure fusion boundary function of 1 / 4 of the MP structure and 1 / 4 of the MW structure; S4: Construct the implicit functions of 1 / 4 of the MP structure and 1 / 4 of the MW structure according to the heterogeneous structure fusion boundary function of 1 / 4 of the MP structure and 1 / 4 of the MW structure; S5: Generate the geometric models of 1 / 4 of the MP structure and 1 / 4 of the MW structure according to the implicit functions of 1 / 4 of the MP structure and 1 / 4 of the MW structure. With the help of modeling software such as Magics, perform operations such as replication, mirroring, and Boolean union to generate the complete cubic MP structure and MW structure.

2. The design method of the heterogeneous energy absorption structure with a three-period minimal surface structure according to claim 1, characterized in that In the above step S1, the triple-periodic minimal surface P function F(P) and W function F(W) are respectively: In the formula, x, y, and z are the coordinate values in the three-dimensional Cartesian coordinate system; t is the offset parameter of the surface function; L is the side length of the unit cell structure. By changing the value of the offset parameter t in the above formula, generate the geometric models of the unit cell structures with different volume fractions.

3. The design method of the heterogeneous energy absorption structure with a three-period minimal surface structure according to claim 2, wherein In the above step S2, the heterogeneous filling design regions of the P structure and the W structure are respectively: Taking the front surface of the cubic envelope contour of the P structure as the reference, the heterogeneous filling design region in the front surface extends symmetrically to both sides along the center line; In the left half region of the front surface, from left to right, the design ratio between the P structure filling design region and the W structure heterogeneous filling design region is greater than or equal to 1 / 2 and less than 1; taking the front surface of the cubic envelope contour of the W structure as the reference, the heterogeneous filling design region in the front surface is distributed along the 45-degree diagonal and extends perpendicularly to both sides of the diagonal; The design ratio between the W structure filling design region and the P structure heterogeneous filling design region distributed along the diagonal length of the front surface is greater than or equal to 1 / 2 and less than 1.

4. The design method of the heterogeneous energy absorption structure with a three-period minimal surface structure according to claim 3, characterized in that In the above step S3, the heterogeneous structure fusion boundary function of 1 / 4 of the MP structure and 1 / 4 of the MW structure is: The fusion boundary function of the vertical heterogeneous structure fusion region of 1 / 4 of the MP structure is: where x, y, and z are the coordinate values in a three-dimensional Cartesian coordinate system; l P is the cell size of the P structure; The two fusion boundary functions of the 45-degree diagonal heterogeneous structure fusion region of 1 / 4 of the MW structure are: where x, y, and z are the coordinate values in a three-dimensional Cartesian coordinate system; l W is the width of the heterogeneous structure filling area; n is the serial number of the fusion boundary function.

5. The method for designing a heterogeneous energy absorption structure with a three-period minimal surface structure according to claim 4, characterized in that In the above step S4, the implicit functions of 1 / 4 of the MP structure and 1 / 4 of the MW are: The implicit function F(MP) of 1 / 4 of the MP structure is: F(MP) = α MP × F(P) + (1 - α MP ) × F(W) where α MP is a weight function constructed based on the heterogeneous structure fusion boundary function G MP in step S3; The implicit function F(MW) of 1 / 4 of the MW structure is: In the formula, is the heterogeneous fusion boundary function in step S3 and is the weight function constructed based on it.

6. The design method of the heterogeneous energy absorption structure with a three - period minimal surface structure according to claim 5, characterized in that In the above step S5, using the modeling software, perform replication and mirroring operations on 1 / 4 of the MP structure and 1 / 4 of the MW structure to obtain 4 1 / 4 of the MP structure and 4 1 / 4 of the MW structure; Then perform the Boolean union operation to obtain the geometric models of the complete cubic MP structure and cubic MW structure.

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