High specific energy absorption multilevel biomimetic cuttlebone structure

Abstract

This invention discloses a high-energy-density multi-layered biomimetic cuttlebone structure, belonging to the field of buffer energy-absorbing structure technology. It comprises: at least two longitudinally stacked chamber units, with a diaphragm between adjacent chamber units; thin-walled units are provided within each chamber unit, extending laterally along the chamber, and composed of thin-walled monomers with different geometric parameters; the cavities of the chamber units are filled with a polymeric elastic material. This invention constructs two-layer and three-layer structures with axial gradient stiffness distribution by controlling the geometric parameters of the thin-walled units. The optimized multi-level structure exhibits clear stepwise buckling failure behavior, high energy-density absorption, and a gradient stress transfer path.

Description

Technical Field

[0001] This invention relates to the field of buffer energy absorption structure technology, specifically to a high-specific-energy-absorbing multi-level biomimetic cuttlebone structure. Background Technology

[0002] With the development of deep space exploration technology, the landing buffer system, as a key component of planetary probes, directly affects the structural integrity and payload reliability of spacecraft. This buffer system, through its energy dissipation mechanism, effectively controls landing impact loads and has become a crucial technical element for the success or failure of deep space exploration missions.

[0003] The current mainstream buffering technologies can be divided into four categories: hydraulic damping systems, electromagnetic active control devices, thin-walled metal tubes, and energy absorption structures based on honeycomb. Among them, honeycomb structures have become the preferred solution for the buffering design of the next generation of landers due to their excellent specific energy absorption effect and structural stability under extreme temperature and radiation environments. However, existing honeycomb structures still have the following technical problems in design: (1) Traditional homogeneous materials and isomorphic arrays are prone to synchronous instability, resulting in a sudden drop in load and low energy absorption efficiency; (2) Failure behavior is uncontrollable, which can easily generate debris splash and cause secondary damage; (3) The interlayer stiffness matching of multi-layer structures is poor, making it impossible to achieve progressive failure; (4) The mechanical properties of conventional polymer materials are greatly reduced under extreme high and low temperature environments, making it difficult to meet the needs of deep space exploration.

[0004] Therefore, there is an urgent need for a high specific energy absorption multi-level biomimetic cuttlebone structure. Summary of the Invention

[0005] The main objective of this invention is to provide a high specific energy absorption multi-level biomimetic cuttlebone structure to solve the technical problems of low energy absorption efficiency, disordered failure, and poor reliability of buffer structures in the prior art.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: A high-energy-absorbing, multi-layered biomimetic cuttlebone structure includes: The high specific energy absorption multi-level biomimetic cuttlebone structure includes at least two longitudinally stacked chamber units, with a diaphragm between adjacent chamber units; each chamber unit contains a thin-walled unit that extends laterally along the chamber and is composed of thin-walled monomers with different geometric parameters; the cavity of each chamber unit is filled with a polymer elastic material.

[0007] Furthermore, the geometric configuration of the thin-walled unit is defined by three parameters: thin-walled amplitude a, thin-walled period b, and offset amplitude c. The upper and lower boundaries of the thin-walled unit are defined by the functions y=a·sin(b·x) and y=0.5·sin(0.5·x), respectively. The range of the thin-walled amplitude a is 1-2; the range of the thin-walled period b is 1-1.5; and the range of the offset amplitude c is 0-2 mm.

[0008] Furthermore, the multiple chamber units are distributed in a height gradient along the longitudinal direction, with the height of the chamber units gradually increasing from the lower to the upper layers.

[0009] Furthermore, the same chamber unit is provided with type A thin-walled monomers, type B thin-walled monomers and type C thin-walled monomers with different geometric parameters.

[0010] Furthermore, the chamber unit has two or three layers. When the chamber unit has a two-layer structure, the lower chamber has a height of 10mm and the upper chamber has a height of 15mm. When the chamber unit has a three-layer structure, the bottom chamber has a height of 8-10mm, the middle chamber has a height of 15mm, and the top chamber has a height of 20-25mm. The thickness of the diaphragm is 2-2.5mm.

[0011] Furthermore, the cross-sectional shape of the chamber unit is circular, square, or polygonal.

[0012] Furthermore, the thin-walled units within the adjacent chamber units are arranged in opposite directions to balance the lateral moment, suppress unilateral buckling, and guide the orderly transmission of stress along the height direction.

[0013] Furthermore, the high specific energy absorption multi-level biomimetic cuttlebone structure is prepared by polymer-based composite material through fused deposition modeling additive manufacturing technology. The polymer-based composite material is a polyphenylene sulfide / polyphenylene ether composite material, wherein the mass percentage of polyphenylene ether is 10-30 wt%.

[0014] Furthermore, the polymeric elastic material is a soft gel, used to suppress debris splashing during structural failure and enhance energy absorption capacity.

[0015] The present invention has the following beneficial effects: 1. This invention constructs two- and three-layer structures with axial gradient stiffness distribution by adjusting the geometric parameters of thin-walled units. The optimized multi-level structure exhibits clear stepwise buckling failure behavior, high specific energy absorption, and a gradient stress transfer path. During compression, the structure enters a brittle failure state sequentially from top to bottom: the upper unit fractures and collapses first, the middle layer maintains overall integrity, stress is smoothly transferred to the middle and bottom layers, and each level sequentially enters a brittle failure state. The failure path unfolds orderly along the height direction without unilateral deflection. This optimized design effectively suppresses asymmetric load transfer and lateral buckling caused by consistent tilt direction, enabling the structure to fully participate in energy absorption at each level, thus forming a gradient energy dissipation mechanism from top to bottom.

[0016] 2. The heterogeneous chamber structure constructed by combining diverse thin-walled units in this invention exhibits significant improvements in three indicators: maximum instantaneous crushing force, specific energy absorption, and displacement, while the stiffness shows a moderate decreasing trend. In the heterogeneous chamber, thin-walled units with different geometric parameters possess different local stiffness and critical failure loads due to differences in amplitude, period, or offset, thus forming a gradient failure sequence during loading.

[0017] 3. In this invention, the gel material effectively suppresses debris splashing. Previous experiments have shown that unfilled structures scatter a large number of fragments after failure, while gel-filled structures, even if partially broken, can still anchor the broken fragments in place through high cohesion and interfacial adhesion, avoiding secondary damage caused by high-speed splashing. This design not only enhances the energy absorption efficiency of the structure but also improves its safety and environmental adaptability during service. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the main structure of the high specific energy absorption multi-level biomimetic cuttlebone structure in an embodiment of the present invention; Figure 2 This is a three-dimensional structural diagram of the high specific energy absorption multi-level biomimetic cuttlebone structure in an embodiment of the present invention; Figure 3 This is a schematic diagram of the quasi-static compression simulation force-displacement curve of the biomimetic cuttlebone thin-walled structure in Embodiment 2 of the present invention (offset 0mm). Figure 4 This is a schematic diagram of the quasi-static compression simulation force-displacement curve of the biomimetic cuttlebone thin-walled structure in Embodiment 2 of the present invention (offset 1mm). Figure 5 This is a schematic diagram of the quasi-static compression simulation force-displacement curve of the biomimetic cuttlebone thin-walled structure in Embodiment 2 of the present invention (offset 2mm). Figure 6 From Figure 3 , Figure 4 , Figure 5A schematic diagram of the specific energy absorption index extracted from it; Figure 7 From Figure 3 , Figure 4 , Figure 5 A schematic diagram of the maximum instantaneous crushing force index extracted from the data; Figure 8 From Figure 3 , Figure 4 , Figure 5 A schematic diagram of the stiffness index extracted from it; Figure 9 This is a schematic diagram of the maximum instantaneous crushing force index in the compression simulation of the single-chamber structure in Embodiment 3 of the present invention; Figure 10 This is a schematic diagram of the specific energy absorption index of the single-chamber structure compression simulation in Embodiment 3 of the present invention; Figure 11 This is a schematic diagram of the stiffness index of the single-chamber structure under compression simulation in Embodiment 3 of the present invention; Figure 12 This is a schematic diagram of the main structure of the double-layer biomimetic cuttlebone structure in Embodiment 4 of the present invention; Figure 13 This is a schematic diagram of the experimental results of the double-layer biomimetic cuttlebone structure under quasi-static compressive load in Embodiment 4 of the present invention; Figure 14 This is a schematic diagram of the finite element simulation results of the double-layer biomimetic cuttlebone structure under quasi-static compressive load in Embodiment 4 of the present invention; Figure 15 This is a schematic diagram of the experimental results of the double-layer biomimetic cuttlebone structure filled with soft gel under quasi-static compressive load in Embodiment 4 of the present invention; Figure 16 This is a schematic diagram of the experimental results of the three-layer biomimetic cuttlebone structure in Embodiment 5 of the present invention under quasi-static compressive load; Figure 17 This is a schematic diagram of the finite element simulation results of the three-layer biomimetic cuttlebone structure under quasi-static compressive load in Embodiment 5 of the present invention; Figure 18 This is a schematic diagram of the experimental results of the three-layer biomimetic cuttlebone landing structure under quasi-static compressive load in Embodiment 6 of the present invention; Figure 19 This is a schematic diagram of the layer-by-layer failure mechanism of the three-layer biomimetic cuttlebone landing gear structure in Embodiment 6 of the present invention; Figure 20 This is a schematic diagram of the dynamic impact test results of the biomimetic cuttlebone landing gear structure in Embodiment 6 of the present invention; Figure 21 This is a schematic diagram comparing the performance of the biomimetic multi-level structure of the landing gear strut in Embodiment 7 of the present invention.

[0019] Among them: 1. Thin-walled unit; 2. Diaphragm; 3. Type A thin-walled monomer; 4. Type B thin-walled monomer; 5. Type C thin-walled monomer. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Experimental methods in the embodiments that do not specify specific conditions are generally performed under conventional conditions. Unless otherwise specified, all raw materials used are commercially available industrial products.

[0021] This invention provides a high-energy-absorbing multilayer biomimetic cuttlebone structure, comprising: at least two longitudinally stacked chamber units, with a diaphragm 2 between adjacent chamber units; thin-walled units 1 extending laterally along the chamber and composed of thin-walled monomers with different geometric parameters within each chamber unit; and a polymeric elastic material filling the cavities of each chamber unit. Multiple chamber units are distributed with a height gradient along the longitudinal direction, with the height gradually increasing from the lower to the upper chamber units. The cross-sectional shape of the chamber units is circular, square, or polygonal. The thin-walled units in adjacent chamber units are tilted in opposite directions to balance lateral moments, suppress unilateral buckling, and guide the orderly transmission of stress along the height direction. The polymeric elastic material is a soft gel, used to suppress debris splashing during structural failure and enhance energy absorption capacity.

[0022] Example 1: Preparation of polyphenylene sulfide (PPS) / polyphenylene oxide (PPO) composite material In this embodiment, the high-energy-absorbing multi-layered biomimetic cuttlebone structure is prepared by polymer-based composite material through fused deposition modeling additive manufacturing technology. The polymer-based composite material is a polyphenylene sulfide / polyphenylene ether composite material, wherein the mass percentage of polyphenylene ether is 10-30 wt%. Specifically, polyphenylene sulfide (PPS) is used as the matrix material and polyphenylene ether (PPO) is used as the reinforcing phase to prepare composite filaments suitable for fused deposition modeling (FDM). PPS and PPO raw materials are premixed in a planetary ball mill according to a predetermined ratio (PPO content of 0 wt%, 10 wt%, 20 wt%, 30 wt%, and 40 wt%) and ball-milled at 400 r / min for 2 hours to ensure uniform dispersion of the two components. Subsequently, the mixture is placed in a vacuum drying oven and dried at 70°C for 6 hours to fully remove adsorbed moisture.

[0023] Composite material filaments were prepared using a twin-screw extrusion system combined with an online traction device. The extrusion system flow channel was divided into four temperature zones: the preheating zone was set at 265±2℃, the two homogenization zones at 275±2℃ and 280±2℃ respectively, and the die extrusion zone at 285±2℃. The main screw speed was set to 50 rpm, and the feed screw speed was set to 30 rpm. The melt was extruded through a 2mm diameter circular die to form a continuous filament bundle. The filament diameter was controlled to be stable at 1.75±0.05mm by adjusting the traction device, which meets the dimensional requirements of standard printed filaments for FDM process.

[0024] Experimental results show that when the PPO content is 20wt%, the composite material has the best comprehensive performance, with tensile strength and modulus increasing by 49.18% and 79.10%, respectively. The notched impact strength is 255.14% higher than that of pure PPS under alternating high and low temperature environments ranging from -50℃ to 120℃, providing a material basis with high strength, high modulus and excellent printing performance for subsequent biomimetic structures.

[0025] Example 2: Design of a biomimetic cuttlebone thin-walled unit In the technical solution of this invention, the geometric configuration of the thin-walled unit is defined by three parameters: the thin-walled amplitude *a*, the thin-walled period *b*, and the offset amplitude *c*. Specifically, the upper boundary of the thin-walled unit is defined by the function *y* = *a* sin(*b* x), and the lower boundary is defined by the function *y* = 0.5* sin(0.5* x), where *x* and *y* are the position coordinates of the curve projected onto the XY plane.

[0026] The offset amplitude c is independent of the two sine functions mentioned above and is used to control the relative offset of the upper and lower curves in the Y direction. Stretching the upper and lower curves into a surface along a preset ridge in the Z direction forms the overall configuration of the thin-walled unit. The amplitude and period of the lower boundary are fixed at 0.5. By adjusting the amplitude a and period b of the upper boundary, a difference is created between the upper and lower curves, resulting in a "saddle-shaped" geometric feature similar to the structure of a cuttlebone after stretching.

[0027] It should be noted that the fixed lower curve in the above embodiments is merely illustrative and the scope of protection of the present invention is not limited thereto. As a more general design approach, the lower curve can also adopt an adjustable parameter design method, that is, the amplitude and period of the lower boundary can also be adjusted according to actual needs, thereby further expanding the flexibility and applicability of the structural design.

[0028] This embodiment is based on biomechanical research on the microstructure of cuttlebone, extracting key geometric parameters of the thin-walled unit. For example, the thin-wall thickness is 0.8 mm, the diaphragm thickness is 1 mm, and the thin-wall height is 15 mm. Using the thin-wall amplitude, period, and offset as variables, three levels are selected respectively: amplitude a = 1, 1.5, 2; period b = 1, 1.25, 1.5; offset c = 0, 1, 2 mm, constructing a three-factor, three-level orthogonal experimental design to systematically explore the influence of each parameter on the mechanical properties of the biomimetic thin-walled structure.

[0029] like Figures 3-8 As shown, the effects of each parameter on structural performance are not independent but exhibit significant coupling effects. This stems from the regulatory role of structural geometry on energy absorption paths, local buckling modes, and stress distribution. Firstly, the offset *c*, a key parameter determining the overall structural symmetry, shows a systematic decreasing trend in specific energy absorption and maximum instantaneous crushing force as its value increases. The fundamental reason for this phenomenon is that the introduction of the offset disrupts the central symmetry of the structure, preventing it from forming a stable and uniform symmetrical buckling mode under axial loads. Instead, the load concentrates on one side of the structure, inducing asymmetrical and unstable local buckling, thereby reducing the effective load-bearing area and energy dissipation efficiency of the overall structure, ultimately manifesting as a decrease in peak force and total energy absorption capacity. However, the stiffness reaches its optimal effect at an offset of 1 mm. This can be attributed to the fact that although the structure deviates from the ideal symmetry at this offset, its mechanical synergy is not completely destroyed. Instead, a pseudo-strengthening effect may occur due to increased local contact area or enhanced constraints, causing a temporary increase in initial stiffness.

[0030] Secondly, the effect of the thin-wall amplitude 'a' is highly dependent on the value of the offset 'c', exhibiting strong parametric coupling characteristics. When the offset is 0 mm (i.e., the structure is completely symmetrical), the values ​​of all three evaluation indicators show a decreasing trend to varying degrees as the amplitude 'A' increases. This is mainly because in symmetrical structures, increasing the amplitude significantly weakens the average thickness of the thin wall, leading to a decrease in the overall structural stiffness and making buckling more likely to occur in the transitional weak areas, thus triggering failure prematurely and reducing the structure's load-bearing capacity and energy absorption efficiency. However, when the offset is 1 mm or 2 mm, the three evaluation indicators show an increasing trend as the amplitude increases. This indicates that in asymmetrical structures, a moderately increased amplitude can effectively compensate for the asymmetry caused by the offset. A larger amplitude can partially offset the stress concentration caused by the offset by increasing the overall profile size and material distribution of the structure, guiding the load to be more evenly distributed in different areas of the structure, thereby delaying local instability and improving the overall load-bearing capacity and energy absorption efficiency.

[0031] Finally, the impact of the thin-walled period *b* on the evaluation indicators is mainly reflected in energy absorption efficiency and peak load-bearing capacity. With increasing period, both specific energy absorption and maximum instantaneous breaking force show a monotonically decreasing trend, while the change in stiffness is not significant. This is because an increased period means an increase in the number of peaks and troughs per unit length, i.e., a significant increase in the fold density of the structure. While high fold density increases the geometric complexity of the structure, it also leads to excessively small spacing between adjacent wave elements, resulting in enhanced mutual constraint. In this mode, the structure completes most of the deformation within a very short compression stroke, and the energy absorption potential of the material is not fully released, thus reducing energy absorption efficiency and peak load-bearing capacity. Furthermore, dense corrugations introduce more internal forming defects, exacerbating local stress concentration, further inducing early micro-damage, and weakening overall mechanical properties. In contrast, stiffness is not sensitive to changes in the thin-walled period, and its fluctuations lack significant regularity. This may be attributed to the offsetting positive and negative effects of high-density folds on initial bending stiffness. To achieve efficient energy dissipation, appropriate geometric parameters should be selected to achieve an optimal balance between material utilization and structural stability.

[0032] Example 3: Design of a Bionic Cuttlebone Single-Cavity Structure Based on the differences in the mechanical properties of different thin-walled units in Example 2, this embodiment constructs a heterogeneous single-chamber structure.

[0033] Specifically, within the same chamber unit, there are three thin-walled monomers with different geometric parameters: Type A (3), Type B (4), and Type C (5). For example, in the ABC configuration, Type A thin-walled monomer 3 has high breaking force (amplitude a=1, period b=1, offset c=0), Type B thin-walled monomer 4 has medium breaking force (amplitude a=1, period b=1.25, offset c=1), and Type C thin-walled monomer 5 has low breaking force (amplitude a=1, period b=1.5, offset c=2). Through this heterogeneous design, a gradient failure sequence of "low-strength unit leading buckling and high-strength unit bearing energy dissipation" is formed under compressive load, effectively extending the energy dissipation path.

[0034] like Figures 9-11As shown, compared to a normalized chamber structure composed of repeated arrangements of single thin-walled units, a heterogeneous chamber structure constructed using a combination of diverse thin-walled units exhibits significant improvements in maximum instantaneous crushing force, specific energy absorption, and displacement, while the stiffness shows a moderate decreasing trend. This indicates that the biomimetic single-chamber structure achieves superior energy dissipation efficiency while maintaining load-bearing capacity. The fundamental mechanism behind this improved comprehensive energy absorption effect lies in the heterogeneous design inducing a non-uniform but controllable stress field evolution and a progressive damage propagation path. In a homogeneous chamber, all thin-walled units have similar failure thresholds, leading to a tendency for synchronous instability during compression, resulting in a sudden drop in load and a shortening of the energy absorption plateau. In a heterogeneous chamber, thin-walled units with different geometric parameters possess different local stiffnesses and critical failure loads due to differences in amplitude, period, or offset, thus forming a gradient failure sequence during loading. That is, the low-strength unit structure buckles first and dissipates some energy, followed by the high-strength unit structure gradually participating in load-bearing, delaying the failure process of the overall structure. This energy release mechanism effectively extends the effective energy absorption path and improves the energy absorption capacity per unit mass. Furthermore, the moderate reduction in stiffness reflects an increase in structural toughness, which helps reduce peak acceleration and mitigate impact damage to sensitive internal components in impact energy absorption applications. Therefore, endowing the chamber structure with diverse thin-walled units not only overcomes the bottlenecks of traditional isomorphic arrays in energy absorption efficiency and deformation stability, but also achieves synergistic optimization of global performance by regulating local mechanical responses.

[0035] Example 4: Bionic Cuttlebone Double-Layer Structure Design This embodiment is inspired by the biological characteristic of cuttlefish bone chambers increasing in height from the ventral to the dorsal side, and constructs a double-layered biomimetic structure. Specifically, as shown... Figure 12 The lower chamber height is set at 10mm, and the upper chamber height is set at 15mm. The lower chamber adopts an ABCBA type thin-walled unit structure, and the upper chamber adopts an ACAC type thin-walled unit structure. The diaphragm thickness is 2mm.

[0036] Through multiple rounds of simulation and iterative optimization, the optimal double-layer structure parameters were finally determined: the lower layer height is 10mm, the upper layer height is 15mm, the membrane thickness is 2mm, the lower thin-wall type is ABCBA combination, the upper thin-wall type is ACAC combination, and the upper and lower thin-wall inclination directions are set opposite to balance the lateral moment and suppress unilateral buckling.

[0037] like Figure 13 and Figure 14A comparative analysis of experimental and finite element simulation results of the double-layer biomimetic structure under quasi-static compressive loading reveals that the response of the double-layer biomimetic structure under quasi-static compression exhibits good consistency with the simulation results. Both show a linear elastic rise in the initial stage, followed by brittle failure, with a sharp drop in load accompanied by structural fragmentation. This verifies the simulation model's accurate predictive ability for the overall structural stiffness, buckling initiation point, and brittle fracture behavior. In the simulation curves, point A corresponds to the critical state where the thin wall of the upper chamber buckles for the first time, and point B is the peak load point, at which point the stress is transferred through the top platform to the undamaged lower chamber, and the overall load-bearing capacity of the structure reaches its limit.

[0038] The combination of soft and hard materials has become an important research direction in the design of buffer energy-absorbing structures. Its core lies in achieving efficient dissipation of impact energy and precise control of structural response through the gradient distribution of material mechanical properties. Based on this, this section describes the filling of cavities in a biomimetic cuttlebone structure, such as... Figure 15 As shown, the test results demonstrate that gel filling exhibits dual advantages in biomimetic multi-chamber structures. Firstly, it significantly enhances energy absorption capacity, resulting in a larger area under the force-displacement curve. This is because the gel effectively dissipates impact energy through viscoelastic deformation and internal friction mechanisms, while simultaneously constraining the buckling behavior of the unit walls and promoting uniform stress distribution. Secondly, the gel material effectively suppresses debris ejection. Previous experiments have shown that unfilled structures eject a large number of fragments after failure, while gel-filled structures, even with localized fractures, can still anchor broken fragments in situ through high cohesion and interfacial adhesion, avoiding secondary damage caused by high-speed ejection. This design not only enhances the energy absorption efficiency of the structure but also improves its safety and environmental adaptability during service.

[0039] Example 5: Biomimetic Cuttlebone Three-Layer Structure Design This embodiment further constructs a three-layer biomimetic structure based on the two-layer structure. When the chamber unit is a three-layer structure, the height of the bottom chamber is 8-10mm, the height of the middle chamber is 15mm, the height of the top chamber is 20-25mm, and the thickness of the diaphragm is 2-2.5mm.

[0040] like Figure 1 and Figure 2 As shown, the bottom chamber height is set to 8mm, the middle chamber height is set to 15mm, and the top chamber height is set to 20mm. The diaphragm thickness between adjacent layers is 2mm. The bottom layer adopts an ABCBA type thin-walled unit structure, the middle layer adopts an ACAC type thin-walled unit structure, and the top layer adopts an ABC type thin-walled unit structure.

[0041] By optimizing the tilt direction of the intermediate and upper thin-walled units, making the tilt directions of the intermediate and upper thin-walled units opposite, the asymmetric load transfer and lateral buckling caused by the consistent tilt direction are effectively suppressed, so that the structure can fully participate in energy absorption at each level and form a gradient energy dissipation mechanism from top to bottom.

[0042] like Figure 16 and Figure 17 As shown, a comparative analysis of the experimental and finite element simulation results of the three-layer biomimetic structure under quasi-static compressive loading reveals that the experimental compression curves and simulation curves show a high degree of agreement in their overall trends, both exhibiting typical multi-level biomimetic structure compressive response characteristics, including elastic rise, multi-stage buckling plateaus, and progressive failure processes. Simulation curves Figure 17 The six key points (af) marked in the figure reveal the mechanical evolution mechanism of the structure from initial loading to complete failure: point a corresponds to the upper chamber reaching the critical yield strength; point b reflects the transitional state of brief stress release after the partial collapse of the upper layer; point c indicates that the load begins to be transferred from the upper layer to the middle layer, and stress redistribution occurs in the interface area; point d shows that the middle layer experiences obvious brittle failure, and the stress field further extends to the lower support area; point e reaches the global peak load, and the structure achieves layer-by-layer failure from top to bottom, maximizing energy absorption capacity; point f corresponds to the complete failure state of the structure, with only the residual skeleton bearing the residual load. This evolution path verifies that the designed multi-level structure has good load transfer order and step-by-step energy dissipation capacity during compression.

[0043] Example 6: Bionic Cuttlebone Landing Shelf Structure This embodiment integrates the three-layer biomimetic structure optimized in Embodiment 5 into the interior of the lander's strut as a core buffer unit. Specifically, the structure, from bottom to top longitudinally, consists of a bottom layer, a middle layer, and a top layer, with chamber heights set at 10mm, 15mm, and 25mm respectively, and a diaphragm thickness of 2.5mm. The thin-walled structures within each chamber are arranged according to the three optimized models A, B, and C from Embodiment 3, with an overall circular cross-section, an outer diameter of 30mm, and a total structural height of 57.5mm (including the upper and lower end caps).

[0044] A biomimetic multi-level structure of additively manufactured pillars was assembled into the inner cavity of the outer cylinder, with a stainless steel pressure column placed on top. The entire assembly was then placed in the center of the upper and lower pressure plates of a universal testing machine to conduct a quasi-static compressive load test on the biomimetic cuttlebone lander structure. Figure 18As shown, the force-displacement curves clearly reveal four typical mechanical response stages during compression of the biomimetic multi-level structure, exhibiting a highly ordered and controllable failure mechanism. The initial stage corresponds to the first instability of the upper structure, where the load rapidly rises to its first peak and then falls back, but the overall process is relatively smooth with no debris generation, and the curve is smooth and continuous. Subsequently, the middle and lower layers gradually collapse, and the curve shows a distinct undulating plateau region. This is due to debris from the upper structure failure embedding into or disturbing the lower structure. Simultaneously, as compression deepens, the peak loads of subsequent layers gradually increase due to geometric design and constraints, and the load-bearing capacity improves step by step. Finally, the densification stage is reached, where the internal space is completely compacted, the stiffness increases sharply, the curve rises steeply, and the structure enters a state of pure mechanical damping.

[0045] like Figure 19 As shown, during the failure process, the thin-walled structure exhibits brittle failure characteristics due to its material properties, rapidly fracturing under load and generating a large number of irregular fragments. These fragments remain in the interlayer voids, becoming an important medium for subsequent stress transfer and energy dissipation. However, the upper and lower ends of the thin wall connected to the diaphragm do not completely disintegrate, but retain some residual structure (i.e., the residual height h at the top). t Residual height h at the bottom b During compression, the two gradually approach each other, and the height at which they first come into contact is defined as the contact height h. c At this point, the structure enters a transition phase: the two remaining end faces and the intermediate debris begin to squeeze, rub against, and further break apart, resulting in a force-displacement curve exhibiting a typical sawtooth-shaped fluctuation trend. As compression continues, the structure gradually becomes denser, while the sharp, remaining portion at the top will be the first to pierce the septum connecting to the next layer, triggering instability and collapse of the next layer. This process not only achieves segmented and controllable energy absorption but also reproduces the highly efficient impact-resistant strategy developed by natural cuttlebone during biological evolution.

[0046] Furthermore, dynamic impact tests were conducted on the biomimetic cuttlebone landing gear structure. An additively manufactured, pillar-like, biomimetic multi-level structure was placed inside the outer cylinder, and a stainless steel pressure column was placed on top of the structure. A drop hammer impact tester was used to impact the top of the pressure column axially with an impact energy of 200J (corresponding to a hammer head mass of 39kg and an impact velocity of 3.2m / s) to evaluate the energy absorption performance of the structure. Figure 20As shown, the test results indicate that the structure basically achieved the design-expected top-down progressive failure mode. The time-force curve exhibits a brief negative fluctuation after the main impact peak. This is mainly due to the inertial effect and sensor response characteristics during dynamic testing. When the top-level structure buckles, the momentum of the indenter and the failed upper element decreases sharply, while the unfailed lower structure experiences instantaneous upward acceleration due to elastic recovery, resulting in a negative curve value. This phenomenon is normal in dynamic testing. Furthermore, the peak load of the impact test was 52794.8 N, significantly higher than the 8344.2 N of static compression. This difference is mainly due to the combined effect of several factors: firstly, the inertial effect inhibits premature local buckling, thereby enhancing the overall load-bearing capacity of the structure; secondly, the propagation of stress waves in the structure causes the load to concentrate in a limited upper region in the initial stage, resulting in an instantaneous stress level far higher than that under quasi-static uniform compression.

[0047] This invention constructs a lightweight, high-energy-absorbing structure with a biomimetic hierarchical configuration through an integrated material and structure design method. It achieves controllable layer-by-layer failure and efficient energy dissipation under impact loads, providing an engineerable technical solution for the design of lightweight, impact-resistant structures under high dynamic load conditions such as probe landing buffers.

[0048] Example 7: Material Comparison Experiment To further verify the influence of intrinsic material properties on the performance of biomimetic structures, the same biomimetic multilevel structure was printed using common plastic polylactic acid (PLA) material, and quasi-static compression tests were conducted under the same experimental conditions. Figure 21 As shown, a systematic comparison of the compressive properties of biomimetic multi-level structures made from PPS / PPO biomimetic composite materials and pure PLA materials was conducted. The results show that compared with PLA, the biomimetic structure constructed from PPS / PPO composite materials achieves a significant leap in energy absorption efficiency and deformation stroke, with a specific energy absorption increase of up to 323.60% and a maximum compressive displacement increase of 50.83%. The bar chart data shows that the specific energy absorption of the PPS / PPO structure reaches 4.02 kJ / kg, far exceeding PLA's 0.949 kJ / kg; simultaneously, its effective deformation stroke reaches 36.2 mm, while the PLA structure enters the densification stage prematurely at only 24 mm. Combined with observation of the actual compression process, it is evident that the PLA structure experiences overall buckling and local torsion before the three layers have completely collapsed and compacted, leading to a rapid increase in load and entry into the pure mechanical damping stage, significantly shortening the energy absorption window. This comparison not only verifies the key influence of the intrinsic properties of materials on structural function but also further establishes the advantages of PPS / PPO biomimetic composite materials in high-performance impact-resistant buffer structures.

[0049] This invention, based on in-depth analysis of the three-dimensional asymmetric microstructure of cuttlebone, establishes a three-variable biomimetic design space by combining thin-wall amplitude, period, and offset amplitude. The parameter coupling mechanism is revealed through quasi-static compression simulation and experimental systems. Building upon this, a heterogeneous single-chamber strategy is proposed. By combining high-, medium-, and low-strength thin-walled units, a gradient failure sequence of "low strength leading, high strength following" is successfully induced, forming multi-level plateaus on the force-displacement curve, extending the energy absorption path, and improving specific energy absorption. Experiments and simulations show a high degree of consistency in macroscopic response, failure sequence, and damage mode, fully verifying the effectiveness of this design in achieving controllable brittle failure.

[0050] Inspired by the biological mechanism of the increasing axial gradient height of cuttlefish bone chambers, this invention constructs two-layer and three-layer biomimetic structures. Through multiple rounds of simulation iterations, key parameters are optimized to ultimately achieve ideal layer-by-layer failure behavior. Simulations and experiments show a high degree of agreement, clearly demonstrating multi-stage buckling plateaus and ordered stress transfer paths. Further, the introduction of gel-based soft filling significantly increases the total energy absorption, and high cohesiveness anchors fragments, completely eliminating the safety hazards of material impact splashes. Finally, the optimized three-layer structure is proportionally integrated into the core buffer unit of the landing gear strut, completing static compression and dynamic impact tests. These tests verify its high specific energy absorption, structural robustness, and controllable failure under simulated landing conditions, providing an innovative solution for deep space probe buffer systems that combines lightweight design, high reliability, and programmable functionality.

[0051] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A high-energy-absorbing, multi-layered biomimetic cuttlebone structure, characterized in that, include: At least two longitudinally stacked chamber units are provided with a diaphragm (2) between adjacent chamber units; each chamber unit is provided with a thin-walled unit (1), which extends laterally along the chamber and is composed of thin-walled monomers with different geometric parameters; the cavity of each chamber unit is filled with a polymer elastic material.

2. The high specific energy absorption multi-level biomimetic cuttlebone structure according to claim 1, characterized in that, The geometric configuration of the thin-walled unit is defined by three parameters: thin-walled amplitude a, thin-walled period b, and offset amplitude c. The upper and lower boundaries of the thin-walled unit are defined by the functions y=a·sin(b·x) and y=0.5·sin(0.5·x), respectively. The range of the thin-walled amplitude a is 1-2; the range of the thin-walled period b is 1-1.5; and the range of the offset amplitude c is 0-2 mm.

3. The high specific energy absorption multi-level biomimetic cuttlebone structure according to claim 1, characterized in that, The multiple chamber units are distributed in a height gradient along the longitudinal direction, with the height of the chamber units gradually increasing from the lower to the upper levels.

4. The high specific energy absorption multi-level biomimetic cuttlebone structure according to claim 1, characterized in that, The same chamber unit is provided with type A thin-walled monomers (3), type B thin-walled monomers (4) and type C thin-walled monomers (5) with different geometric parameters.

5. The high specific energy absorption multi-level biomimetic cuttlebone structure according to claim 1, characterized in that, The chamber unit has two or three layers. When the chamber unit has two layers, the lower chamber has a height of 10 mm and the upper chamber has a height of 15 mm. When the chamber unit has three layers, the bottom chamber has a height of 8-10 mm, the middle chamber has a height of 15 mm, the top chamber has a height of 20-25 mm, and the diaphragm (2) has a thickness of 2-2.5 mm.

6. The high specific energy absorption multi-level biomimetic cuttlebone structure according to claim 1, characterized in that, The cross-sectional shape of the chamber unit is circular, square, or polygonal.

7. The high specific energy absorption multi-level biomimetic cuttlebone structure according to claim 1, characterized in that, The thin-walled units within the adjacent chamber units are arranged in opposite directions to balance the lateral moment, suppress unilateral buckling, and guide the orderly transmission of stress along the height direction.

8. The high specific energy absorption multi-level biomimetic cuttlebone structure according to claim 1, characterized in that, The high specific energy absorption multi-level biomimetic cuttlebone structure is prepared by polymer-based composite material through fused deposition modeling additive manufacturing technology. The polymer-based composite material is a polyphenylene sulfide / polyphenylene ether composite material, wherein the mass percentage of polyphenylene ether is 10-30 wt%.

9. The high specific energy absorption multi-level biomimetic cuttlebone structure according to claim 1, characterized in that, The polymeric elastic material is a soft gel used to suppress debris splashing during structural failure and to enhance energy absorption capacity.

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