Design method of energy-absorbing bionic lattice structure

Abstract

The invention relates to an energy-absorbing bionic lattice structure design method, which belongs to the technical field of bionics, and is characterized in that a bionic tendon wave lattice structure is designed by referring to an ostrich metatarsophalangeal joint tendon collagenous fiber bundle microstructure in nature; the energy absorption characteristic of the structure is analyzed through tests and simulation, and optimal structure parameters are obtained in combination with a genetic algorithm; the superelastic material and the bionic tendon wave lattice structure are selected to be combined, the diversified requirements of different products for mechanical properties can be effectively met, and in multiple application occasions, impact energy can be efficiently dispersed and absorbed, movement impact force can be effectively dispersed, and a high-quality damping effect can be provided.

Description

Technical Field

[0001] The present invention relates to the field of bionic technology, and in particular to a design method for an energy-absorbing bionic lattice structure. Background Art

[0002] Traditional lattice structures have the following limitations in practical applications: First, stress concentrations are easily generated at joints, potentially leading to overall structural failure; second, the mechanical responses of most lattice structures exhibit significant anisotropy in different directions; and third, under high-frequency cyclic loading, lattice structures are susceptible to fatigue fracture due to the accumulation of microcracks. Optimizing the lattice structure based on bionic principles can effectively improve stress distribution, enhancing the dynamic performance and energy absorption efficiency of the structure.

[0003] The remarkable shock-absorbing and energy-absorbing properties exhibited by organisms in nature provide valuable biomimetic references for solving these problems. The ostrich is a typical animal that locomotes by toe-strike. Its metatarsophalangeal joint is always permanently off the ground, resulting in an up-and-down motion during movement, providing excellent shock absorption. The metatarsophalangeal joint is home to structures such as tendons, tendon sheaths, and bone joints. Research has shown that tendons not only connect the ostrich's toe to the bone and store energy for shock absorption, but also maintain the metatarsophalangeal joint in a permanent position off the ground while absorbing and dissipating impact forces. Longitudinal sections of the tendon proximal to the metatarsophalangeal joint reveal a wavy pattern of collagen fiber bundles. This structure allows the collagen fiber bundles to stretch and deform elastically when the ostrich's foot strikes the ground, converting some of the kinetic energy into the tendon's elastic potential energy. Upon lifting off the ground, the collagen fiber bundles gradually return to their wavy shape, converting the elastic potential energy into kinetic energy.

[0004] Based on the wavy structure of collagen fiber bundles in the metatarsophalangeal joint tendon of ostriches and combined with the spatial distribution of atoms in traditional lattice structures, a bionic tendon wavy lattice structure was invented. The energy absorption characteristics of the structure were analyzed experimentally, and the optimal parameters of the structure were obtained by combining genetic algorithms. The structure has significant energy absorption characteristics.

[0005] In recent years, breakthroughs in additive manufacturing technology, particularly precision fabrication techniques like selective laser sintering and stereolithography, have provided a foundation for the physical fabrication of lattice structures using hyperelastic materials. These materials can overcome the energy dissipation mechanisms of metals and plastics, achieving reversible absorption of impact energy through hyperelasticity. Summary of the Invention

[0006] The purpose of the present invention is to address the shortcomings of traditional lattice structures in the background technology and to provide a method for designing an energy-absorbing bionic lattice structure. The method draws on the microstructure of collagen fiber bundles in the metatarsophalangeal joint tendon of ostriches in nature to design a bionic tendon wave lattice structure; the energy absorption characteristics of the structure are analyzed through experiments and simulations, and the optimal structural parameters are obtained by combining a genetic algorithm; the structure has significant energy absorption characteristics.

[0007] A method for designing an energy-absorbing bionic lattice structure comprises the following steps: Step 1: Place any plane of the face-centered cubic unit cell structure on the XY plane, set the plane as the bottom plane, the plane corresponding to the bottom plane as the top plane, and the remaining planes as adjacent planes; Step 2: Fill the wavy structure of the ostrich metatarsophalangeal joint tendon collagen fiber bundle into the face-centered cubic unit In the cell structure, circular rods are used for connection, and the spatial position of the central atoms of the adjacent faces changes with the angle of the wave-like structure, thus constructing a bionic tendon wave cell structure; Step 3: The size of the bionic tendon wave unit cell structure is 10 mm × 10 mm × 10 mm. The angle of the wavy structure is the internal angle, ranging from 90° to 130°, and the diameter of the round rod is 1.32 mm to 2.45 mm, that is, the porosity is between 80% and 50%; Step 4: The bionic tendon wave unit cell structure is linearly arrayed to obtain a bionic tendon. Wavy lattice structure.

[0008] The bionic tendon wave lattice structure is prepared using SP10 photosensitive resin superelastic material with a hardness of 64A and adopts photocuring molding technology.

[0009] The energy absorption characteristics of the bionic tendon wave lattice structure are analyzed through quasi-static compression tests and finite element simulations, and the optimal parameters are obtained by combining genetic algorithms.

[0010] The bionic tendon wave lattice structure is formed by 3D printing.

[0011] Beneficial effects of the present invention: The bionic lattice structure designed by the method described in the present invention has significant energy absorption characteristics and has broad practical application prospects. By selecting a superelastic material and combining it with the bionic tendon wave lattice structure, it can effectively adapt to the diversified requirements of different products for mechanical properties. In many application scenarios, it can efficiently disperse and absorb impact energy, effectively disperse the impact force of movement, and provide high-quality shock absorption effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1This is a microscopic structure diagram of the ostrich metatarsophalangeal joint tendon of the present invention; Figure 2 This is a three-dimensional schematic diagram of the bionic tendon wave lattice structure of the present invention; Figure 3 This is a front view of the bionic tendon wave lattice structure of the present invention; Figure 4 This is a schematic diagram of the bionic tendon wave unit cell structure of the present invention; Figure 5 This is a parameter diagram of the bionic tendon wave unit cell structure of the present invention; Figure 6 Schematic diagram of the spatial distribution of atoms in a face-centered cubic unit cell structure; Figure 7 Schematic diagram of the face-centered cubic unit cell structure; Figure 8 This is a structural diagram of the external straight rod and internal straight rod of the bionic tendon wave unit cell structure of the present invention; Figure 9 This is a graph showing the experimental data of the peak force and specific energy absorption of the bionic tendon wave lattice structure of the present invention.

[0013] Reference numerals: bionic tendon wavy lattice structure 1 , bionic tendon wavy unit cell structure 10 , external straight rod 11 , internal straight rod 12 . DETAILED DESCRIPTION

[0014] See also Figures 1 to 9 Shown is an embodiment of the present invention.

[0015] The present invention designs a bionic tendon wave lattice structure 1 based on the wavy microstructural characteristics of the collagen fiber bundles of the ostrich metatarsophalangeal joint tendon and the atomic distribution position of the face-centered cubic unit cell structure.

[0016] like Figure 1 As shown, the collagen fiber bundles in the ostrich metatarsophalangeal joint tendons exhibit a wavy structure, with distinct peaks and troughs, and a regular, dense arrangement. At the moment of foot contact, the collagen fiber bundles undergo ductile deformation under the force, converting some of the impact kinetic energy into elastic potential energy of the tendon tissue, thereby achieving efficient energy absorption. During liftoff, the collagen fiber bundles gradually return to their inherent wavy form through an elastic recovery mechanism, converting the stored elastic potential energy back into kinetic energy, effectively reducing the foot's ground contact stiffness and movement vibration.

[0017] like Figure 2 and Figure 3 As shown, the bionic tendon wavy lattice structure 1 is obtained by rectangularly arraying the bionic tendon wavy unit cell structures 10 on the X, Y, and Z axes. In this embodiment, the bionic tendon wavy unit cell structures 10 are arrayed 4 times on the X, Y, and Z axes.

[0018] like Figure 4 As shown, the bionic tendon wave unit cell structure 10 includes an external straight rod 11 and an internal straight rod 12 , and the internal straight rod 12 is embedded in the external straight rod 11 .

[0019] like Figure 5 As shown, the geometric parameters of the bionic tendon wave unit cell structure 10 include: internal angle θ , beam diameter d and the unit cell side length l . Beam diameter d The porosity variation of the lattice structure can be controlled.

[0020] The outer straight rod 11 is obtained based on a face-centered cubic unit cell structure.

[0021] like Figure 6 and Figure 7 As shown, a face-centered cubic unit cell is placed in a fixed position: any plane of the face-centered cubic unit cell is placed in the XY plane, and this plane is set as the bottom plane, the plane corresponding to the bottom plane is the top plane, and the remaining planes are adjacent planes. The atomic positions of the bottom and top planes remain unchanged. The central atomic position of the adjacent plane can be moved in space along the X-axis or Y-axis. As the face-centered cubic unit cell structure mentioned above has a completely symmetrical geometric structure, the above placement position can also be the other two planes, namely the XZ or YZ plane.

[0022] like Figure 8 As shown, the central atom of the outer straight rod 11 is the central atom of the adjacent face of the face-centered cubic unit cell structure, and the position of the central atom changes with the internal angle of the inner straight rod 12.

[0023] Internal straight rod 12 is derived from the wavy shape of collagen fiber bundles in the ostrich metatarsophalangeal joint tendon to create a single internal angle rod. The angle of the internal angle rod ranges from 90° to 130°. The internal angle rod 12 is formed by four circular arrays with the Z axis as the reference direction and a rotation angle of 90°.

[0024] The size of the bionic tendon wave unit cell structure 10 is 10 mm × 10 mm × 10 mm, and the diameters of the outer straight rods 11 and the inner straight rods 12 are between 1.32 mm and 2.45 mm, that is, the porosity is 80% to 50%.

[0025] The material of the bionic tendon wave lattice structure 1 is SP10 photosensitive resin, which has a hardness of 64A and a density of 1.07 g / cm 3 Specifically, a TAPS 400 / 400P high-speed light-curing 3D printer was used for manufacturing, and the printing layer thickness was selected to be 0.1 mm.

[0026] The bionic tendon wavy lattice structure of this embodiment was subjected to quasi-static compression testing and finite element simulation analysis with a compression displacement of 30 mm to analyze its energy absorption performance. The results show that, at the same porosity, as the internal angle increases, the deformation stability deteriorates, the specific energy absorption, peak force, and average force show an increasing trend, and the crushing force efficiency shows an initial increase followed by a decrease. At the same internal angle, as the porosity increases, the deformation stability gradually weakens, the specific energy absorption, peak force, and average force show a decreasing trend, while the crushing force efficiency shows an increasing trend. Using specific energy absorption and peak force as optimization targets, a multi-objective optimization of the bionic tendon wavy lattice structure was performed using a genetic algorithm, resulting in the optimal solution for the lattice structure parameters.

[0027] like Figure 9 As shown in the figure, the optimal solutions of lattice structure parameters, the three optimal combinations with the highest levels are: Group A [ δ , θ ]=[60.98, 122.99], Group B[ δ , θ ]=[60.10, 125.78], Group C[ δ , θ ]=[59.32, 128.75]. δ represents the porosity of the biomimetic tendon wave lattice structure, θ Represents the inner angle. The specific energy absorption of the three combinations were 0.29 J / g, 0.32 J / g, and 0.35 J / g, and the peak forces were 771.56 N, 927.83 N, and 1068.84 N, respectively. Comprehensive considerations showed that group B [ δ , θ ]=[60.10, 125.78] is the optimal parameter scheme, that is, the bionic tendon wave lattice structure with a porosity of 60.10% and an internal angle of 125.78° has the highest energy absorption performance.

Claims

1. A method for designing an energy-absorbing bionic lattice structure, characterized by: The following steps are involved: Step 1: Place any plane of the face-centered cubic unit cell structure on the XY plane, set the plane as the bottom plane, the plane corresponding to the bottom plane as the top plane, and the remaining planes as adjacent planes; Step 2: Fill the wavy structure of the ostrich metatarsophalangeal joint tendon collagen fiber bundle into the face-centered cubic unit cell structure and connect them with round rods. The spatial position of the central atoms of the adjacent faces changes with the angle of the wavy structure, thus constructing a bionic tendon wavy unit cell structure; Step 3: The size of the bionic tendon wave unit cell structure is 10 mm × 10 mm × 10 mm, the angle of the wave structure is an internal angle ranging from 90° to 130°, and the diameter of the round rod is 1.32 mm to 2.45 mm, that is, the porosity is between 80% and 50%; Step 4: The bionic tendon wave unit cell structure is linearly arrayed to obtain a bionic tendon wave lattice structure.

2. The method for designing an energy-absorbing bionic lattice structure according to claim 1, characterized in that: The bionic tendon wave lattice structure is prepared using SP10 photosensitive resin superelastic material with a hardness of 64A and adopts photocuring molding technology.

3. The method for designing an energy-absorbing bionic lattice structure according to claim 1, characterized in that: The energy absorption characteristics of the bionic tendon wave lattice structure are analyzed through quasi-static compression tests and finite element simulations, and the optimal parameters are obtained by combining genetic algorithms.

4. The method for designing an energy-absorbing bionic lattice structure according to claim 1, wherein: The bionic tendon wave lattice structure is formed by 3D printing.

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