Three-period minimal curved surface hybrid multi-platform graded energy absorption structure design method based on hyperbolic tangent function

Abstract

According to the method, TPMS fusion based on the hyperbolic tangent function is described, and TPMS of different structures and different volume fractions is selected, so that energy absorption grading is achieved. By fusing TPMS of different structures and volume fractions, energy absorption grading can be achieved, and the requirements in different application scenes are met. A flexible optimization method is provided, hybrid fusion is performed by using a hyperbolic tangent function, parameters are optimized by changing different volume fractions, and the energy absorption characteristic of the material can be flexibly adjusted. The material is manufactured through 3D printing, the material based on the TPMS structure has good mechanical performance and energy absorption capacity, and the comprehensive performance of the material can be further improved through the fused structure. Through the design strategy, the overall energy absorption performance of the structure can be remarkably improved. The combined design enables the structure to absorb and disperse energy more effectively when the structure is impacted or loaded, so that the safety and durability of the structure are improved.

Description

Technical Field

[0001] The present invention relates to the field of material science and engineering, and is a triply periodic minimal surfaces (TPMS) fusion technology based on a hyperbolic tangent function. The technology realizes an innovative method of energy absorption classification by selecting TPMS with different structures and volume fractions. Background Art

[0002] In modern design, collision energy absorption technology is widely used to improve safety in collision accidents and reduce damage to people and machines. Collision energy absorption refers to the design of special structures or materials during the collision process so that the collision energy is effectively absorbed and dispersed, thereby reducing the damage to the structure or human body caused by the collision. Collision energy absorption technology is an indispensable part of modern design and is of great significance for improving collision safety and reducing damage to people and machines. With the continuous advancement of science and technology and people's constant pursuit of safety, collision energy absorption technology will continue to be widely used and developed.

[0003] At present, the energy absorption structure is mainly composed of a single structure filling. Although it can play a buffering role and reduce the impact force during collision, it can only achieve the energy absorption effect of a single platform. Some complex hybrid structure models are almost impossible to achieve by hand drawing, which greatly limits the creativity and design freedom of designers. The design in this application aims to create a structure with multi-platform graded energy absorption capacity by combining the characteristics of the hyperbolic tangent function and the geometric advantages of the three-period minimal surface, so as to effectively reduce energy transfer and protect key components when impacted. Through Matlab programming, on the basis of a uniform three-period minimal surface lattice, a mixed three-period minimal surface lattice is designed to achieve a multi-level energy absorption (multi-level platform) and a multi-level protection integrated porous structure to achieve a multi-level energy absorption effect. Compared with a single three-period minimal surface lattice, a multi-level three-period minimal surface lattice has a higher specific energy absorption. A multi-level energy absorption (multi-level platform) and a multi-level protection integrated porous structure are achieved. The multi-stage energy absorption characteristics of the hybrid TPMS lattice were studied, and the effects of the hybrid three-periodic minimal surface configuration, transition layer width, volume fraction and hybridization mode on the multi-stage energy absorption were obtained. Therefore, it is necessary to design a multi-level energy absorption structure to solve the above problems. Summary of the invention

[0004] The present invention provides a method for realizing energy absorption classification based on TPMS fusion with hyperbolic tangent function. The present invention can obtain materials with excellent energy absorption capacity by selecting TPMS with different structures and volume fractions and fusing and optimizing them with hyperbolic tangent function. The method has broad application prospects in the fields of materials science, protective engineering, etc.

[0005] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0006] The present invention provides a method for realizing energy absorption classification based on TPMS fusion of hyperbolic tangent function, and realizes energy absorption classification by fusing TPMS with different structures and different volume fractions to meet the needs of different application scenarios. For each selected TPMS, its mechanical properties and energy absorption capacity are changed by adjusting its volume fraction. The volume fraction refers to the proportion of the TPMS structure in the material.

[0007] Preferably, three TPMS configurations, namely, Gyroid (G), Schwarz Primitive (P), and I-WP Surface (I-WP), are selected for hybridization to achieve three-level platform energy absorption. The present invention provides the above three configurations, but is not limited to the three configurations and quantities.

[0008] The present invention provides a TPMS configuration hybrid modeling method described in the above technical solution, comprising the following steps:

[0009] The level set approximation equation of TPMS is:

[0010]

[0011]

[0012]

[0013] The selected TPMS are fused using the hyperbolic tangent function. By adjusting the parameters of the hyperbolic tangent function, the weights of different TPMS in the fusion process can be controlled, thereby achieving energy absorption classification.

[0014] Hyperbolic tangent function expression:

[0015] The isosurface function is used to extract isosurfaces, based on implicit function expressions for different TPMS configurations. The function creates isosurfaces based on scalar data on a 3D grid.

[0016] Use the isocaps function to generate the face and vertex data of a closed isosurface and merge the face and vertex data.

[0017] Use the stlwrite function to save the merged face and vertex data and name it as an stl file called "Hybrid".

[0018] Assemble the exported "Hybrid" stl file model with the end block and output it as a whole.

[0019] It was prepared by 3D printing and tested, using PETG as the material. The test results show that by introducing different types or different numbers of TPMS cells into the same structure along the loading direction, the deformation may be preferentially transferred from the lattice structure with low yield strength to the TPMS structure with high yield strength. In this way, the function of the hybrid TPMS lattice can be realized. The multi-level energy absorption hybridization method shows that the multi-level energy absorption effect can be achieved based on the sequential hybridization of the TPMS lattice yield strength along the loading direction.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] A single TPMS structure may not achieve the best energy absorption effect in all cases. This application integrates TPMS with different structures and volume fractions, and through 3D printing technology, it can directly convert the digital model into a physical structure, which can achieve energy absorption grading to meet the needs of different application scenarios. Function modeling also reduces manufacturing errors. By using hyperbolic tangent functions for fusion and optimizing parameters through numerical optimization methods, the energy absorption characteristics of the material can be flexibly adjusted. The material based on the TPMS structure has good mechanical properties and energy absorption capacity, and the fused material can further improve its comprehensive performance.

[0022] The present invention provides a method for realizing energy absorption classification based on TPMS fusion with hyperbolic tangent function. Because a single TPMS structure may not achieve the best energy absorption effect in all cases, the present invention selects TPMS with different structures and volume fractions, and uses hyperbolic tangent function for fusion and optimization to obtain a structure with excellent energy absorption capacity. The method has broad application prospects in the fields of materials science, protective engineering, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 The present invention is a flow chart of hybrid structure design;

[0024] Figure 2 Schematic diagram of the TPMS unit cell structure;

[0025] Figure 3 Schematic diagram of TPMS hybrid connection arrangement;

[0026] Figure 4 Schematic diagram of transition width at TPMS hybrid connection;

[0027] Figure 5 It is a schematic diagram of loading of the structure experiment of the embodiment of the present invention;

[0028] Figure 6 It is a stress-strain diagram of an example test of the present invention;

[0029] Figure 7is an energy absorption-strain diagram of an example test of the present invention; DETAILED DESCRIPTION

[0030] The following will elaborate on the drawings and technical solutions in the embodiments of the present invention to provide a complete description of the examples of the present invention. It should be clear that the examples described here are only part of the many possible embodiments of the present invention, not all of them. The number of hybridizations, hybridization order and hybridization direction shown in the drawings are only schematic and can be customized as needed. In addition, based on the embodiments presented in the present invention, all other embodiments that can be derived by ordinary technicians in this field without creative work should also be deemed to be included in the scope of protection of the present invention.

[0031] The purpose of the present invention is to achieve energy absorption classification by integrating TPMS with different structures and different volume fractions and optimizing parameters using the hyperbolic tangent function to meet the needs of different application scenarios. Through the differences in the mechanical properties of different three-periodic minimal surfaces, hybrid mixing is performed to optimize the transition section of the connection. A hybridization method based on the hyperbolic tangent function is provided, and the mutual fusion of multiple hyperbolic tangent functions is realized through Matlab. The fusion of multiple three-periodic minimal surface configurations can be realized, thereby achieving multi-platform energy absorption. The technical solution adopted by the present invention to solve this problem is as follows

[0032] First, TPMS selection, choose a variety of TPMS with different structures, such as Gyroid, Schwarz Primitive (P), I-WP, etc. These structures have different mechanical properties and energy absorption characteristics. Including a variety of three-periodic minimal surface structures, the mathematical expressions are:

[0033] Primitive:

[0034] Gyroid:

[0035] I-WP:

[0036] The Matlab mathematical expression is:

[0037]

[0038]

[0039] w=2[cos(\frac {k*2\pi} {L\_ cell}*x)cos(\frac {k*2\pi} {L\_ cell}*y)+cos(\frac {k*2\pi} {L\_ cell}*y)cos(\frac {k*2\pi} {L\_ cell}*z)+cos(\frac {k*2\pi} {L\_ cell}*z)cos(\frac {k*2\pi} {L\_ cell}*x)]-[cos(2\frac {k*2\pi} {L\_ cell}*x)+cos(2\frac {k*2\pi} {L\_ cell}*y)+cos(2\frac {k*2\pi} {L\_ cell}*z)]+c

[0040] The size of a single unit cell can be changed by changing "L_cell", the number of single unit cells in the x, y, and z horizontal directions can be changed by changing "k", and the unit cell morphology can be changed by changing the "c" value. By adjusting the parameters, hybrid TPMS structures with different mechanical properties can be obtained, and the design of multi-platform graded energy absorption structures can be realized.

[0041] The selected TPMS are fused using the hyperbolic tangent function. The hyperbolic tangent function is an S-shaped curve function with a range between -1 and 1, which is suitable for smoothly fusing multiple inputs into one output. By adjusting the parameters of the hyperbolic tangent function, the weights of different TPMS in the fusion process can be controlled, thereby achieving energy absorption classification.

[0042] Hybrid hyperbolic tangent equation:

[0043]

[0044]

[0045] By adjusting the value of "h", the transition width "s" of connections with different configurations can be achieved. The larger the "h" value, the narrower the transition, and vice versa.

[0046] Preferably, "h=1" is selected in the present application, and then the design variables can be assigned values ​​according to design requirements.

[0047] Specific steps of modeling: Write code in Matlab to generate STL file:

[0048] Use the isosurface function to extract the isosurface:

[0049] In MATLAB, it is used to draw isosurface graphs. According to the implicit function expressions of different TPMS configurations, the function creates isosurfaces based on scalar data on a three-dimensional grid, that is, draws an isosurface in three-dimensional space, which is composed of isolines of a scalar field. In order to meet the definition of a three-periodic minimal surface in mathematics, a minimal surface refers to a surface with a mean curvature of zero. Therefore, an isosurface with a value equal to 0 is extracted from the scalar field s on the three-dimensional grid defined by x, y, and z.

[0050] The programming code is: [F,V]=isosurface(x,y,z,s,0);

[0051] Among them, F is the index array of the face and V is the coordinate array of the vertex.

[0052] Use the isocaps function to generate the face and vertex data of a closed isosurface. A drawing function in MATLAB that is used to draw the contour lines of a three-dimensional curve graph. Because the previously generated isosurface is not closed, the function is called to generate a closed (or "capped") isosurface.

[0053] The programming code is: [FC,VC]=isocaps(x,y,z,s,0);

[0054] Among them, FC is the index array of the faces of the closed isosurface, and VC is the coordinate array of the vertices of the closed isosurface.

[0055] Merge all face and vertex data. Since the face indices generated by isocaps are based on its own vertex set (VC), the indices in (FC) need to be offset to match the entire vertex set (the vertex set after V and VC are merged). Here FC+length(V(:,1)) offsets the face indices generated by Isocaps so that they refer to the entire merged vertex set.

[0056] The programming code is: F = [ F ; FC+length(V(:,1))];

[0057] Use the stlwrite function to save the merged face and vertex data as an stl file named "NAME".

[0058] The programming code is: stlwrite(['PG-IWP.STL'],F,V)

[0059] At this point, the TPMS modeling part has been drawn, and end blocks are assembled at both ends of the model (the size of the end blocks can be customized according to requirements). Then, through 3D printing technology, the digital model can be directly converted into a physical structure for printing and manufacturing. For the volume fraction adjustment, for each selected TPMS, the design variables are assigned according to the design requirements. Its mechanical properties and energy absorption capacity are changed by adjusting its volume fraction. The designed 3D model is imported into the slicing software for processing. The slicing file contains the shape, size and height information of each layer during the printing process, as well as the material type and thickness required for printing. After importing the slicing file into the 3D printer, printing preparation is required. Load the PETG printing material into the printer and start printing. The production method adopts the fused deposition modeling (FDM) 3D printing technology with PETG as the raw material, and the model is manufactured by a 3D printer.

[0060] Through the hybrid distribution of different types of lattices, multi-stage deformation (multi-stage protection) and multi-stage energy absorption (multi-stage platform) are achieved. The hyperbolic tangent function is used to achieve smooth transition between different types of TPMS structures, and a hybrid TPMS lattice is designed. The multi-stage energy absorption of the hybrid TPMS lattice is verified through quasi-static compression experiments. The results show that the introduction of different types of TPMS along the loading direction can achieve multi-stage energy absorption, which is beneficial to improve the overall energy absorption.

[0061] The present invention describes a TPMS fusion based on a hyperbolic tangent function, selects different structures and different volume fractions, and realizes energy absorption grading of TPMS with different structures. By fusing TPMS with different structures and volume fractions, energy absorption grading can be realized to meet the needs of different application scenarios. A flexible optimization method is proposed, which uses a hyperbolic tangent function for fusion, and optimizes the parameters by changing different volume fraction methods, so that the energy absorption characteristics of the material can be flexibly adjusted. Manufactured by 3D printing, the material based on the TPMS structure has good mechanical properties and energy absorption capacity, and the fused material can further improve its comprehensive performance. Through the above design strategy, the overall energy absorption performance of the structure can be significantly improved. This combined design enables the structure to absorb and disperse energy more effectively when impacted or loaded, thereby improving its safety and durability.

Claims

1. A TPMS energy absorption structure based on hyperbolic tangent function hybridization and a preparation method thereof, characterized in that include: The three-periodic minimal surfaces (TPMS) with different structures and different volume fractions are fused; The hyperbolic tangent function is used to optimize the parameters of the fused TPMS to achieve energy absorption classification to meet the needs of different application scenarios; hybrid mixing is performed according to the differences in mechanical properties of different three-periodic minimal surfaces, and the connected transition sections are optimized to improve the stability and energy absorption effect of the overall structure; a hybrid method based on the hyperbolic tangent function is provided, and the mutual fusion of multiple hyperbolic tangent functions is realized through Matlab software to accurately control the fusion process and optimize parameters.

2. The TPMS energy absorption structure based on the hyperbolic tangent function hybridization according to claim 1, characterized in that: The TPMS with different structures and different volume fractions include but are not limited to Schwartz D surface, Schwartz P surface, IWP surface or a combination thereof, and their volume fractions are adjustable within a preset range.

3. The TPMS energy absorption structure based on the hybridization of the hyperbolic tangent function according to claim 1 or 2, characterized in that: The step of using the hyperbolic tangent function to optimize parameters includes: determining the parameters of the hyperbolic tangent function, including the center position, slope, etc., to reflect the energy absorption requirements in different application scenarios; applying the hyperbolic tangent function to the geometric parameters or material properties of the TPMS, and performing continuous or segmented adjustments to achieve energy absorption grading.

4. The TPMS energy absorption structure based on the hyperbolic tangent function hybridization according to any one of claims 1 to 3, characterized in that: The hybrid mixing method includes: analyzing the difference in mechanical properties of different TPMS to determine the hybridization ratio and hybridization position; adopting transition section design to optimize the hybridization interface to ensure the strength and stability of the structural connection.

5. The TPMS energy absorption structure based on the hyperbolic tangent function hybridization according to any one of claims 1 to 4, characterized in that: The fusion of multiple hyperbolic tangent functions implemented by the Matlab software includes: defining multiple hyperbolic tangent functions, each function corresponding to a different TPMS or a different optimization target; adjusting the parameters of each hyperbolic tangent function through an algorithm so that they can work together to achieve a complex energy absorption classification effect.

6. The method for preparing a TPMS energy absorption structure based on hyperbolic tangent function hybridization according to any one of claims 1 to 5, characterized in that: include: Design TPMS models with different structures and volume fractions; The model is optimized using the hyperbolic tangent function to determine the optimal parameters; a hybrid design is performed based on the optimized parameters, and the connection transition section is optimized; the effectiveness of the design is verified through numerical simulation or experiments, and necessary adjustments are made.

7. Application of the TPMS energy absorption structure based on hyperbolic tangent function hybridization as claimed in any one of claims 1 to 6 in the fields of transportation, building structures, protective equipment, etc.

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