Deep sea landing buffer design method and system based on filling optimization TPMS structure

Abstract

The invention belongs to the technical field of deep sea landers, and discloses a deep sea landing buffer design method and system based on a filling optimization TPMS structure, and the method comprises the steps: S1, designing and preparing a filling TPMS structure; s2, performing a quasi-static compression test on the filled TPMS structure; s3, carrying out a dynamic impact performance test on the filled TPMS structure; s4, based on a result of the quasi-static compression test and a result of the dynamic impact performance test, selecting a filling TPMS structure meeting a preset requirement, and designing a buffer system of the deep sea lander; and S5, optimizing the buffer system of the deep sea lander according to different application scenes and equipment requirements. The possibility that the TPMS structure is filled with the magnetic fluid is further explored, the novel TPMS filling structure is applied to a deep sea landing buffer, and an efficient buffer solution is provided for deep sea detection equipment.

Description

Technical Field

[0001] The present invention belongs to the technical field of deep-sea landers, and in particular relates to a deep-sea landing buffer design method and system based on a filling optimized TPMS structure. Background Art

[0002] The deep sea has attracted humans with its mystery and unknown since ancient times, and exploring marine resources and the environment has always been a long-term goal of mankind. Before the mid-20th century, detection equipment was mainly dropped underwater through cables for environmental measurement and resource exploration. However, with the increase in detection depth, the required cable length and the complexity of the supporting system have increased significantly, which not only increases the inconvenience of transportation and operation, but also causes the equipment to be disturbed by the ocean current, seriously affecting the detection function. To solve this problem, Maurice Ewing and Allyn Vine of the Woods Hole Oceanographic Institution in the United States first proposed the concept of "free submersible" (Free Vehicle) in 1938, separating the center of gravity and buoyancy by weights and floats to achieve stable landing of the detection equipment. This innovation has promoted the development of cable-free deep-sea detection equipment.

[0003] With the rapid development of deep-sea exploration technology, high-performance, integrated buffering and energy-absorbing materials have become an indispensable key technology in deep-sea landers. The deep-sea environment is significantly different from the ground conditions. The complex underwater loads and uncertain terrain place strict requirements on the impact buffering performance of the equipment. Improperly designed buffer structures will not only accelerate equipment aging and shorten service life, but may even lead to the failure of the exploration mission. In the deep-sea landing process, efficient energy absorption performance has become a core factor in ensuring the reliability of exploration equipment.

[0004] In recent years, lightweight porous structures and thin-walled energy-absorbing structures have shown broad application prospects in deep-sea landers due to their efficient energy absorption characteristics. These new energy-absorbing structures use structural deformation to effectively dissipate energy through optimized design, providing reliable equipment protection. However, traditional foam materials and honeycomb structures are difficult to meet the needs of high-performance energy-absorbing structures for deep-sea exploration missions due to their random microstructures, poor adjustability, short service life, and insufficient ability to process complex morphologies. Therefore, it has become a top priority to develop efficient energy-absorbing materials and design methods suitable for deep-sea environments. Tri-periodic minimal surface (TPMS) structures filled with porous materials have become a potential solution. This type of material has excellent mechanical properties and cushioning properties due to its unique periodicity and pore distribution. Studies have shown that a well-designed TPMS structure not only has the advantage of lightweight, but also can further improve energy absorption efficiency by filling a variety of materials. For example, filling porous materials such as honeycomb steel tubes and truss structures with elastic materials such as foamed aluminum and polymer foam has been shown to significantly improve the strength and energy absorption capacity of the structure. However, the matching problem between the filler and the structure during compression still affects the energy dissipation efficiency and the reusability of the structure. In addition, granular materials have shown extensive application potential in external impact energy absorption and pulse wave dissipation due to their unique rheological properties. Particle fillers can not only adapt to the compression of porous structures, but also improve the overall performance through inter-particle friction and energy dissipation paths within the material.

[0005] During the landing of a deep-sea lander, the lattice structure will encounter low-speed impact events. Although it is difficult to observe significant damage on the surface, serious damage such as cracks, fractures, or interlayer separation may have occurred inside the structure. These damages will gradually accumulate, reducing the bearing capacity of the structure and even leading to functional failure, resulting in economic losses and safety risks. Existing research mainly focuses on the performance evaluation of metal TPMS structures and gradient structures, while there are relatively few studies on the response and energy absorption capacity of material-filled TPMS structures under dynamic impact conditions, as well as quasi-static compression tests. Therefore, it is of great significance to conduct in-depth research on the impact resistance and energy absorption characteristics of material-filled TPMS structures during the landing of deep-sea landers, which can effectively improve the performance of such filler structures in high-demand application fields.

[0006] Although previous studies have shown that filler type and proportion have an important influence on energy absorption characteristics, there is no systematic analytical framework for the mechanism of how fillers in TPMS structures improve energy absorption efficiency. There is still significant room for research on the effects of different proportions of materials on the energy absorption performance of TPMS structures under quasi-static and dynamic conditions. Therefore, the development of TPMS structures filled with high-performance materials and their optimized design methods have important application value in improving the cushioning performance and energy absorption efficiency of deep-sea landers. Summary of the invention

[0007] In order to solve the problems existing in the prior art, the present invention provides a deep-sea landing buffer design method and system based on filling optimization TPMS structure. Through implicit functions and three-dimensional modeling technology, three TPMS structures with different configurations are designed, and combined with sealing and end cap design to meet the filling material requirements. High-precision samples are manufactured using fused deposition modeling (FDM) technology, and structures with three filling material ratios (0%, 50%, and 100%) are designed. The filling effect is verified by mass analysis evaluation. Based on quasi-static compression tests, the energy absorption characteristics of TPMS structures under different filling material ratios are systematically studied, and the differences in deformation mode and energy absorption performance of the three configurations are compared. The influence of multiple factors on the performance of TPMS structures is further explored through single-factor tests with different placement times, filling material particle sizes, and loading speeds. In the dynamic impact test, impact experiments with energy levels from 20J to 300J were carried out for TPMS structures with different filling material ratios, and high-speed camera technology was used to accurately capture the dynamic deformation mode and obtain the stress-strain curve and time-energy curve. Through quantitative analysis, the influence of the filling material ratio on the impact resistance of the TPMS structure is deeply revealed. Research has shown that filling materials significantly improve the energy absorption performance of TPMS structures, providing important ideas for the development and application of high-performance filling materials. In addition, the present invention further explores the possibility of filling TPMS structures with magnetic fluids, and applies this new type of filled TPMS structure to deep-sea landing buffers, providing an efficient buffer solution for deep-sea exploration equipment.

[0008] To achieve the above object, the present invention provides the following solutions:

[0009] A deep-sea landing buffer design method based on filling optimization TPMS structure, the method comprising:

[0010] S1: Design and preparation of filled TPMS structure;

[0011] S2: quasi-static compression test of the filled TPMS structure;

[0012] S3: Dynamic impact performance test of the filled TPMS structure;

[0013] S4: Based on the results of the quasi-static compression test and the dynamic impact performance test, select the filling TPMS structure that meets the preset requirements and design the buffer system of the deep-sea lander;

[0014] S5: Optimize the buffer system of the deep-sea lander according to different application scenarios and equipment requirements.

[0015] Preferably, in S1, designing and preparing a filled TPMS structure includes:

[0016] Design three different TPMS structures;

[0017] Designing a TPMS sealing structure, wherein the design of the TPMS sealing structure includes: thin-wall design and end cover design;

[0018] Prepare and fill TPMS structure samples;

[0019] preparing filling materials;

[0020] Filling the prepared filling material into the prepared filled TPMS structure sample and performing a repeatability experimental test;

[0021] Among them, three different TPMS structures are designed:

[0022] φ p (x,y,z)=cosx+cosy+cosz=c

[0023] φ G (x,y,z)=cosxsiny+cosysinz+coszsinx=c

[0024] φ D (x,y,z)=sinxsinysinz+cosxinysinz+

[0025] sinxcosysinz+sinxsinycosz=c

[0026] Among them, φ P (x,y,z),φ G (x,y,z),φ D (x, y, z) are the equations of the primitive surface (P), the gyroid surface (G), and the diamond surface (D), respectively. x, y, z are the coordinates in three-dimensional space, describing the geometric position of the TPMS. c is a constant used to describe the value of the level set corresponding to the TPMS surface.

[0027] Among them, preparing the filled TPMS structure sample includes: using 3D printing technology to manufacture the TPMS lattice structure and top seal;

[0028] The preparation of the filling material includes: drying the filling material; after drying, storing the filling material in a constant temperature and humidity chamber; further pre-screening the filling material and classifying it into three categories according to particle size: 0.15 mm, 0.65 mm and 0.85 mm.

[0029] Preferably, in S2, performing a quasi-static compression test on the filled TPMS structure includes:

[0030] Select the testing machine and force sensor range that meet the preset requirements, combine three structural configurations, different rest times, particle sizes and loading speeds, and select three samples for repeated tests;

[0031] Five key indicators were used to analyze the test results and obtain the energy absorption results of three configurations with different filling ratios;

[0032] Analyze the standing time, filler material particle size, and loading speed;

[0033] By analyzing the deformation records of the first cycle compression, different configurations of TPMS with the same relative density are selected, and the influence of different filling ratios on the deformation mode of the TPMS structure is analyzed;

[0034] Among them, the five key indicators include:

[0035] Energy Absorption EA: Among them, S is the displacement of strain, F(s) represents the force corresponding to a certain point in the deformation process, m represents the mass, and SEA represents the specific energy absorption, that is, the energy absorbed per unit mass;

[0036] Specific energy dissipation SED: Where ED is the energy dissipated during the cyclic compression test, and is the area under the hysteresis curve;

[0037] Remaining energy dissipation percentage: Among them, @current cycle indicates the current cycle, and @1st cycle indicates the first cycle;

[0038] Deformation recovery rate; R = (1-ε r )×100%; where ε r is the residual strain, R is the deformation recovery rate;

[0039] Damping characteristics;

[0040] Five key indicators were used to analyze the test results, including: separate comparative analysis of different filling ratios of different configurations, and comprehensive comparative analysis of different filling ratios of different configurations.

[0041] Preferably, in S3, performing a dynamic impact performance test on the filled TPMS structure includes:

[0042] The specimen to be tested is placed on a rigid plate, and a heavy hammer is made to fall freely and vertically to the surface of the specimen under the action of gravity through a double rail system to apply impact force, and the voltage change at the contact point between the punch and the specimen during the impact process is captured and recorded. By converting the voltage data, a curve representing the contact force, displacement, velocity and energy between the punch and the specimen over time is generated, and the dynamic response of the specimen under different impact energies is analyzed, wherein the dynamic response includes deformation, crack generation and internal damage extension;

[0043] By adjusting the mass of the hammer or the height between the hammer and the specimen, the initial impact energy is controlled, and the impact test is performed to analyze the energy absorption capacity and impact resistance of the specimen under different impact energies;

[0044] By applying different levels of impact energy to simulate impact conditions from mild to extreme, the energy absorption efficiency of the specimen under different impact energies is analyzed;

[0045] By analyzing the deformation records of the first cycle compression, different configurations of TPMS with the same relative density are selected, and the influence of different filling ratios on the deformation mode of the TPMS structure is analyzed;

[0046] Among them, the initial impact energy is controlled by adjusting the mass of the hammer head or the height between the hammer head and the test piece. The impact test includes:

[0047] During the impact process, the falling of the hammer head is regarded as free fall motion, and the reduced gravitational potential energy is converted into the impact kinetic energy E applied to the specimen:

[0048]

[0049] In the formula, v0 is the initial velocity of the hammer head when it contacts the specimen, and U is the gravitational potential energy of the falling hammer;

[0050] High-energy impact tests are controlled by adjusting the weight and height of the drop hammer; the test equipment captures the load data when the punch contacts the specimen and calculates the change in the drop hammer velocity over time:

[0051]

[0052] Where, v(t) is the speed of the hammer at time t. When v(t)>0, the punch moves downward. When v(t)<0, the punch rebounds and moves upward. t is time. F(t) is the contact force between the hammer and the specimen at time t.

[0053] After the specimen is impacted, the absorbed energy of the specimen is converted from the kinetic energy of the punch:

[0054]

[0055] In the formula, E ais the energy absorbed by the specimen during the impact;

[0056] Among them, the impact conditions ranging from mild to extreme are simulated by applying different levels of impact energy, including:

[0057]

[0058] In the formula, E a Indicates the absorbed energy of the specimen; E i represents impact energy; η is energy absorption efficiency.

[0059] Preferably, in S4, based on the results of the quasi-static compression test and the results of the dynamic impact performance test, a filling TPMS structure that meets the preset requirements is selected, and the design of the buffer system of the deep-sea lander includes:

[0060] Based on the results of the quasi-static compression test and the results of the dynamic impact performance test, the P configuration with the best filling effect and the D configuration with the strongest load-bearing capacity were selected;

[0061] The P configuration with the best filling effect and the D structure with the strongest bearing capacity are designed as a two-stage energy absorption structure.

[0062] The present invention also provides a deep-sea landing buffer design system based on a filling optimized TPMS structure, the system is used to implement any one of the methods described, the system comprising: a first design module, a static test module, a dynamic test module, a second design module and an optimization module;

[0063] The first design module is used to design and prepare a filling TPMS structure;

[0064] The static test module is used to perform a quasi-static compression test on the filled TPMS structure;

[0065] The dynamic test module is used to perform a dynamic impact performance test on the filled TPMS structure;

[0066] The second design module is used to select a filling TPMS structure that meets preset requirements and design a buffer system for the deep-sea lander based on the results of the quasi-static compression test and the results of the dynamic impact performance test;

[0067] The optimization module is used to optimize the buffer system of the deep-sea lander according to different application scenarios and equipment requirements.

[0068] Preferably, in the first design module, designing and preparing a filling TPMS structure includes:

[0069] Design three different TPMS structures;

[0070] Designing a TPMS sealing structure, wherein the design of the TPMS sealing structure includes: thin-wall design and end cover design;

[0071] Prepare and fill TPMS structure samples;

[0072] preparing filling materials;

[0073] Filling the prepared filling material into the prepared filled TPMS structure sample and performing a repeatability experimental test;

[0074] Among them, three different TPMS structures are designed:

[0075] φ p (x,y,z)=cosx+cosy+cosz=c

[0076] φ G (x,y,z)=cosxsiny+cosysinz+coszsinx=c

[0077] φ D (x,y,z)=sinxsinysinz+cosxinysinz+

[0078] sinxcosysinz+sinxsinycosz=c

[0079] Among them, φ P (x,y,z),φ G (x,y,z),φ D (x, y, z) are the equations of the primitive surface (P), the gyroid surface (G), and the diamond surface (D), respectively. x, y, z are the coordinates in three-dimensional space, describing the geometric position of the TPMS. c is a constant used to describe the value of the level set corresponding to the TPMS surface.

[0080] Among them, preparing the filled TPMS structure sample includes: using 3D printing technology to manufacture the TPMS lattice structure and top seal;

[0081] The preparation of the filling material includes: drying the filling material; after drying, storing the filling material in a constant temperature and humidity chamber; further pre-screening the filling material and classifying it into three categories according to particle size: 0.15 mm, 0.65 mm and 0.85 mm.

[0082] Preferably, in the static test module, performing a quasi-static compression test on the filled TPMS structure includes:

[0083] Select the testing machine and force sensor range that meet the preset requirements, combine three structural configurations, different rest times, particle sizes and loading speeds, and select three samples for repeated tests;

[0084] Five key indicators were used to analyze the test results and obtain the energy absorption results of three configurations with different filling ratios;

[0085] Analyze the standing time, filler material particle size, and loading speed;

[0086] By analyzing the deformation records of the first cycle compression, different configurations of TPMS with the same relative density are selected, and the influence of different filling ratios on the deformation mode of the TPMS structure is analyzed;

[0087] Among them, the five key indicators include:

[0088] Energy Absorption EA: Among them, S is the displacement of strain, F(s) represents the force corresponding to a certain point in the deformation process, m represents the mass, and SEA represents the specific energy absorption, that is, the energy absorbed per unit mass;

[0089] Specific energy dissipation SED: Where ED is the energy dissipated during the cyclic compression test, and is the area under the hysteresis curve;

[0090] Remaining energy dissipation percentage: Among them, @current cycle indicates the current cycle, and @1st cycle indicates the first cycle;

[0091] Deformation recovery rate; R = (1-ε r )×100%; where ε r is the residual strain, R is the deformation recovery rate;

[0092] Damping characteristics;

[0093] Five key indicators were used to analyze the test results, including: separate comparative analysis of different filling ratios of different configurations, and comprehensive comparative analysis of different filling ratios of different configurations.

[0094] Preferably, in the dynamic test module, the dynamic impact performance test of the filled TPMS structure includes:

[0095] The specimen to be tested is placed on a rigid plate, and a heavy hammer is made to fall freely and vertically to the surface of the specimen under the action of gravity through a double rail system to apply impact force, and the voltage change at the contact point between the punch and the specimen during the impact process is captured and recorded. By converting the voltage data, a curve representing the contact force, displacement, velocity and energy between the punch and the specimen over time is generated, and the dynamic response of the specimen under different impact energies is analyzed, wherein the dynamic response includes deformation, crack generation and internal damage extension;

[0096] By adjusting the mass of the hammer or the height between the hammer and the specimen, the initial impact energy is controlled, and the impact test is performed to analyze the energy absorption capacity and impact resistance of the specimen under different impact energies;

[0097] By applying different levels of impact energy to simulate impact conditions from mild to extreme, the energy absorption efficiency of the specimen under different impact energies is analyzed;

[0098] By analyzing the deformation records of the first cycle compression, different configurations of TPMS with the same relative density are selected, and the influence of different filling ratios on the deformation mode of the TPMS structure is analyzed;

[0099] Among them, the initial impact energy is controlled by adjusting the mass of the hammer head or the height between the hammer head and the test piece. The impact test includes:

[0100] During the impact process, the falling of the hammer head is regarded as free fall motion, and the reduced gravitational potential energy is converted into the impact kinetic energy E applied to the specimen:

[0101]

[0102] In the formula, v0 is the initial velocity of the hammer head when it contacts the specimen, and U is the gravitational potential energy of the falling hammer;

[0103] High-energy impact tests are controlled by adjusting the weight and height of the drop hammer; the test equipment captures the load data when the punch contacts the specimen and calculates the change in the drop hammer velocity over time:

[0104]

[0105] Where, v(t) is the speed of the hammer at time t. When v(t)>0, the punch moves downward. When v(t)<0, the punch rebounds and moves upward. t is time. F(t) is the contact force between the hammer and the specimen at time t.

[0106] After the specimen is impacted, the absorbed energy of the specimen is converted from the kinetic energy of the punch:

[0107]

[0108] In the formula, E ais the energy absorbed by the specimen during the impact;

[0109] Among them, the impact conditions ranging from mild to extreme are simulated by applying different levels of impact energy, including:

[0110]

[0111] In the formula, E a Indicates the absorbed energy of the specimen; E i represents impact energy; η is energy absorption efficiency.

[0112] Preferably, in the second design module, based on the results of the quasi-static compression test and the results of the dynamic impact performance test, a filling TPMS structure that meets the preset requirements is selected, and the design of the buffer system of the deep-sea lander includes:

[0113] Based on the results of the quasi-static compression test and the results of the dynamic impact performance test, the P configuration with the best filling effect and the D configuration with the strongest load-bearing capacity were selected;

[0114] The P configuration with the best filling effect and the D structure with the strongest bearing capacity are designed as a two-stage energy absorption structure.

[0115] Compared with the prior art, the present invention has the following beneficial effects:

[0116] 1. The present invention studies TPMS structures with different sand filling ratios, and shows greatly different stress-strain relationships and deformation modes under quasi-static compression loads. Compared with the unfilled structure, the 50% filled TPMS structure shows a more significant stress increase in the plastic plain stage after the elastic stage, which indicates that the filling treatment not only changes the deformation mode of the TPMS structure, but also improves its energy absorption capacity and recoverability.

[0117] 2. There are certain differences in the effects of filling on TPMS structures of different configurations under quasi-static compression tests. Under the same filling ratio conditions, the specific energy consumption (SED) of the Diamond (D) surface structure is better than that of the Gyroid (G) surface structure and higher than that of the Primitive (P) surface structure. The filling material increases the bearing capacity of the structure and improves the energy absorption performance of the structure. In terms of improving the energy absorption performance of the structure, the SED of the filled structure can be increased by up to 1.48 times, and the energy dissipation rate can be increased by up to 20.5%. In addition, the improvement in the energy absorption performance of the P structure by filling is the best among the three TPMS configurations, indicating that the improvement of the filling on the TPMS structure with weaker energy absorption is more obvious.

[0118] 3. During the dynamic impact of the drop hammer, the deformation mode and stress-strain curve of the filled TPMS structure under low energy impact (20J) are similar to those under quasi-static loading conditions. Under medium energy impact (40J, 80J), the unfilled TPMS structure exhibits higher load-bearing capacity and higher stiffness, but at the same time, more obvious damage occurs inside the structure, while the 50% filled and 100% filled structures exhibit lower peak loads and less structural damage. The friction of the filling material absorbs most of the energy and reduces the degree of damage to the structure. Under high energy impact (160J, 300J), the unfilled TPMS structure presents a state of complete failure and complete densification, but the 100% filled TPMS structure shows a force-displacement curve trend similar to that of low energy impact. This shows that the filling material significantly improves the energy absorption characteristics of the structure under high-speed impact, and at the same time plays a significant protective role in the structure, enabling it to cope with higher energy impact without affecting performance. This fully demonstrates the excellent performance of the filled material TPMS structure in terms of impact resistance, energy absorption, protection and shock absorption.

[0119] 4. The present invention has conducted a detailed exploration of its performance under quasi-static and dynamic loading conditions through experimental means, and found that the filling material significantly improved the energy absorption characteristics of the TPMS structure, providing a new idea for the development of high-performance filling materials. The possibility of filling the TPMS structure with magnetic fluid was explored, and this new type of filled TPMS structure was applied to deep-sea landing buffers, providing an efficient buffer solution for deep-sea exploration equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0120] In order to more clearly illustrate the technical solution of the present invention, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0121] Figure 1 A schematic diagram of a reliable sealing design method for a TPMS structure according to an embodiment of the present invention;

[0122] Figure 2 Schematic diagram of energy absorption results of three configurations with different filling ratios according to an embodiment of the present invention, wherein (a) is specific energy consumption; (b) is residual energy dissipation rate; (c) is energy dissipation rate; (d) is deformation recovery rate;

[0123] Figure 3 Schematic diagram of the test results of three types of filled P structures under different filling particle size test conditions of the embodiment of the present invention, wherein (a) is the specific energy consumption; (b) is the residual energy dissipation rate; (c) is the deformation recovery rate; (d) is the energy dissipation rate;

[0124] Figure 4 It is a schematic diagram of some test analysis results of simulating impact conditions from mild to extreme by applying different levels of impact energy according to an embodiment of the present invention;

[0125] Figure 5 This is a schematic diagram of a circular mapping structure based on a P structure according to an embodiment of the present invention;

[0126] Figure 6 This is a schematic diagram of a buffer system of a deep-sea lander according to an embodiment of the present invention;

[0127] Figure 7 A schematic diagram of a deep-sea landing buffer design method based on a filling optimized TPMS structure according to an embodiment of the present invention;

[0128] Description of the drawings: 1—Circular mapping structure based on TPMS filling P structure; 2—Circular mapping structure based on TPMS filling D structure; 3—Electromagnetic coil; 4—Spring; 5—Repeatably compressible soft film; 6—Structural design of the landing legs and base of the cushioning lander. DETAILED DESCRIPTION

[0129] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0130] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0131] Embodiment 1

[0132] like Figure 7 As shown, the present invention provides a deep-sea landing buffer design method based on a filling optimized TPMS structure, the method comprising:

[0133] S1: Design and preparation of filled TPMS structure;

[0134] S2: quasi-static compression test of the filled TPMS structure;

[0135] S3: Dynamic impact performance test of the filled TPMS structure;

[0136] S4: Based on the results of the quasi-static compression test and the dynamic impact performance test, select the filling TPMS structure that meets the preset requirements and design the buffer system of the deep-sea lander;

[0137] S5: Optimize the buffer system of the deep-sea lander according to different application scenarios and equipment requirements.

[0138] In this embodiment, step S1: design and preparation of a filling TPMS structure:

[0139] S11: Geometric design of traditional TPMS structure:

[0140] In the above method, in step S1, the parameter coordinates of the three-periodic minimal surface (TPMS) can be derived by the Weierstrass function. The geometric structure of the TPMS can be solved by the following mathematical expression:

[0141]

[0142] Among them, Re is the coefficient obtained by calculating the value from the fixed point ω0 to a variable point ω, x, y, z are the coordinates in three-dimensional space, calculated by the parameterized equation, describing the geometric position of the TPMS, R(τ) is a function related to the TPMS surface, describing the surface shape and geometric structure, θ is a variable used to describe the polar coordinate angle on the surface, τ is a variable used to describe the change of the TPMS surface parameterization, and defines the integral path. In this form, the parameterized coordinates of the TPMS surface can be obtained. Next, the geometric structure of the TPMS is derived using the level set approximation equation defined by the Fourier series. The equation is as follows:

[0143]

[0144] Among them, Ψ(r) is the function that characterizes the level set and is used to generate the geometry of the TPMS through Fourier series expansion, k is the reciprocal vector, α(k) is the phase shift, the structure factor F(k) is the amplitude associated with a given k, and r is the vector of spatial positions. When the series is truncated to the leading term, a function φ consisting of a combination of trigonometric functions is generated, which satisfies the following equation:

[0145] φ(x,y,z)=c

[0146] Among them, c is a constant used to describe the value of the level set corresponding to the TPMS surface. It determines the specific shape and position of the generated TPMS surface in space. By adjusting the value of c, the geometric characteristics of the TPMS surface, such as the thickness, curvature and other parameters of the surface, can be adjusted.

[0147] Finally, the mathematical expression of the TPMS surface is obtained:

[0148]

[0149] in, They are the equations of Primitive surface (P), Gyroid surface (G) and Diamond surface (D). And by adjusting the c value, the TPMS opening structure size, volume fraction, aperture size and thickness can be adjusted.

[0150] S12: TPMS closed structure design:

[0151] The structure is further designed while the values ​​of the TPMS opening structure size, volume fraction, aperture size and thickness obtained in step S11 remain unchanged. Thin walls and end caps are added to achieve structural sealing, thereby obtaining the design of the TPMS sealing structure. In order to reduce the impact of thin walls on subsequent tests, the thin wall design needs to be as thin as possible (30×30×0.65mm thin wall) while meeting the processing requirements of additive manufacturing equipment. Commercial modeling software (Materialise Magics 23.0) is used to add thin walls to the outside of the original opening structure, trying to reduce the impact on the deformation of the structure (three configurations: Primitive (P), Diamond (D) and Gyroid (G)). In addition, an independent end cap is designed by interference fit to connect with the sealing structure. The thickness and size of the end cap (the inner size of the end cap is 29.8×29.8mm, the wall thickness is 0.65mm, and the height of the end cap is set to 6mm to minimize the impact on the deformation of the structure itself while ensuring the cover fits firmly) are optimized to ensure that the sealing requirements are met while minimizing the impact on the structural performance. This design method achieves reliable sealing of the TPMS structure and provides a solid foundation for subsequent tests. Figure 1 As shown:

[0152] S13: Preparation of filled TPMS structure samples:

[0153] The TPMS lattice structure and top seal were manufactured using 3D printing technology. First, a 3D printer JG MakerA6 (JG Aurora, China) was used to generate a slice file based on the "STL" file of the TPMS lattice structure. Next, the filamentary thermoplastic polyurethane (TPU) material was heated to an appropriate melting temperature, extruded through the printer nozzle, and stacked layer by layer to form the desired mechanical device structure. The process included adjusting the setting parameters of the 3D printer and the material parameters as shown in Tables 1 and 2 below to ensure printing quality and product performance.

[0154] Table 1 3D printer setting parameters

[0155]

[0156] Table 2 3D printing material parameters

[0157]

[0158] S14: Preparation of filling material:

[0159] The solid particle filler is pretreated to ensure the stability of its mechanical properties. First, the filler material is dried using an electric blast drying oven with a set temperature of 60°C and a drying time of 12 hours. After drying, the filler material is stored in a constant temperature and humidity chamber with a temperature of 25°C and a humidity of 50%. In view of the fact that the mechanical properties of granular materials are significantly affected by their size and shape, the filler material is further pre-screened and classified into three categories according to particle size: 0.15mm, 0.65mm and 0.85mm.

[0160] S15: Fill the filling material in step S14 into the TPMS structure prepared in step S13, and perform a repeatability test (the mass before and after filling is measured for four samples of each configuration. The average value of the mass after filling is used as the standard mass filled in the structure (100% filling ratio) to minimize the influence of structural printing errors). In the four repeated tests, the relevant data such as the mass of the filling material, the mass of the TPMS structure, and the mass of the TPMS after filling in each test are measured and recorded, and their average values ​​are calculated.

[0161] Step S2: The present invention studies the energy absorption characteristics and recoverability of the TPMS structure under three different filling material ratios (0%, 50%, 100%), covering three configurations: Primitive (P), Diamond (D) and Gyroid (G). Further single-variable experiments are carried out on the filled Primitive (P) structure to examine factors such as the placement time, particle size and loading speed of the filling material, and to analyze the effects of different loading conditions and filling material ratios on the recoverability of the TPMS structure. A quasi-static compression test was performed 20 times, and the energy absorption and recoverability of structures with no filling material, loose filling material and dense filling material under quasi-static compression conditions were evaluated through force-displacement curve analysis. This step helps to optimize the energy absorption and recovery capabilities of the TPMS structure and demonstrate the potential of the filler-containing structure.

[0162] Step S21: Preparatory stage for quasi-static compression test of TPMS filling structure, select appropriate testing machine and force sensor range. To ensure equipment safety and improve data accuracy, select appropriate force sensor range, so as to avoid damage to the instrument due to excessive stress, and ensure sensitivity to small force value changes. The present invention uses 3369 Instron testing machine (range 50kN) for testing, and performs quasi-static compression tests on TPMS structures with filling ratios of 0%, 50% and 100%. The crosshead rate of the testing machine is set to 2mm / min, 20 cycles are loaded, and the displacement is 15mm. During the test, three structural configurations, different resting times (four resting times: 0, 5, 30 and 60 minutes; particle diameters, 0.15mm and 0.85mm respectively; two quasi-static compression loading speeds of 2mm / min and 500mm / min), particle size and loading speed and other variables are considered, and three samples are selected for repeated tests to verify the reliability of the results. The specimen is placed in the center of the instrument base, with the loading direction parallel to the FDM construction direction. The deformation behavior and damage mode are recorded by a camera to evaluate the mechanical properties and energy absorption capacity of the TPMS structure.

[0163] Step S22: Through the experiment, capability analysis indicators are set, and five key indicators are used to analyze the test results. These indicators are used to systematically evaluate the validity and reliability of the test data.

[0164] Performance indicator 1: Energy absorption (EA) refers to the total energy absorbed by the structure; it is defined as the envelope area of ​​the force-displacement curve:

[0165]

[0166] Among them, S is the displacement of strain, usually compressed to the strain point where densification begins, F(s) represents the force corresponding to a certain point in the deformation process, usually the force exerted on the material under strain S, m represents mass, usually refers to the total mass of the material or system involved in energy absorption or deformation, SEA (Specific Energy Absorption) represents specific energy absorption, that is, the energy absorbed per unit mass, which is an important indicator for measuring the energy absorption performance of materials or structures, defined as the ratio of total absorbed energy EA to mass m. Due to the change in the porous characteristics of the structure during the filling process of the TPMS structure, the trend of the force-displacement curve shows a characteristic change of early densification, which also affects the energy efficiency and the occurrence law of peak force. Therefore, the densification start strain is predefined as a strain value of 50%, and the compression displacement is set to 15mm to ensure consistency. m is the mass of the structure. To ensure consistent structural dimensions, the construction dimensions of all structures in this article are 30*30*30mm.

[0167] Performance index 2: Specific energy dissipation (SED) is one of the important indicators for evaluating energy absorption performance. The larger the SED, the stronger the energy dissipation capacity of the structure. SED is calculated using the area under the hysteresis loop:

[0168]

[0169] where ED is the energy dissipated during the cyclic compression test and is the area under the hysteresis curve.

[0170] Performance indicator 3: The residual energy dissipation percentage is a measure of the change ratio of SEA in the cycle test, that is, the energy attenuation, which is defined as the SED of the current cycle divided by the SED of the first cycle, that is:

[0171]

[0172] Among them, @current cycle represents the current cycle, and @1st cycle represents the first cycle.

[0173] Performance indicator 4: Deformation recovery rate is the ratio of the sample height at the end of compression to the original height of the sample before compression. It is an important indicator to measure the ability of the structure to recover its shape.

[0174] R=(1-ε r )×100%

[0175] Among them, ε r is the residual strain, and R is the deformation recovery rate.

[0176] Performance index 5: Damping characteristics refer to the ability of a material to absorb vibration (cyclic stress) through internal friction and convert mechanical energy into heat energy. The present invention uses the damping capacity SDC to evaluate the damping capacity of the structure.

[0177]

[0178] A higher SDC indicates a greater proportion of energy dissipated relative to total energy absorbed, which is beneficial for an energy absorber. This means that if more energy is dissipated after an impact with the same energy input, less energy is returned to the impacted component, thereby protecting the external structure from the impact.

[0179] Step S23: Analyze the experimental results according to the performance indicators in step S22. First, conduct a separate comparison and analysis of different filling ratios of different configurations, and finally conduct a comprehensive comparative analysis. Some experimental results are as follows: Figure 2 As shown, the energy absorption results of three configurations with different filling ratios are (a) specific energy consumption (b) residual energy dissipation rate (c) energy dissipation rate (d) deformation recovery rate.

[0180] Among them, separate comparison analysis:

[0181] 1. Analysis of the influence of filling materials on P structure performance

[0182] The force-displacement curves of P at three filling ratios (0%, 50%, 100%) were plotted. The test results of the 1st, 10th and 20th cycles of the same filling ratio and the same configuration were selected for comparative analysis.

[0183] Then the curves were drawn using the above four energy parameter indicators (specific energy consumption, residual energy dissipation rate, deformation recovery rate, and energy dissipation rate). The test results of 1-20 cycles were selected to compare and analyze the P configurations with different filling ratios (0%, 50%, and 100%).

[0184] 2. The analysis method of the influence of filling materials on the performance of G structure is the same as that of the analysis method of the influence of filling materials on the performance of P structure.

[0185] 3. The analysis method of the influence of filling materials on the performance of D structure is the same as that of the analysis method of the influence of filling materials on the performance of P structure.

[0186] Comprehensive comparative analysis: Compare and discuss the P, D and G configurations studied. Figure 2 Shown are the (a) specific energy consumption, (b) residual energy dissipation rate, (c) energy dissipation rate, and (d) deformation recovery rate of all sand-filled structures of the three TPMS configurations in the 1st, 2nd, and 20th cycles.

[0187] Step S24: In addition to the comparative analysis of different filling ratios and different configurations in step S23, the present invention also analyzes other influencing factors:

[0188] Resting time: the time interval between the end of each loading cycle and the beginning of the next loading cycle. The present invention sets four resting times: 0, 5, 30 and 60 minutes. Among them, resting time: compares the specific energy consumption, residual energy dissipation rate, energy dissipation rate, and deformation recovery of the structure under different resting times. The graph is roughly as follows Figure 2 , the other two are the same as above.

[0189] Filler particle size: A variety of filler particle diameters with the most significant differences within the size limit were selected to explore the effect of particle size on the performance of the filled structure. This difference in particle size leads to different gap sizes inside the structure, which in turn affects the change in filling quality. Among them, the filler particle sizes are 0.15mm and 0.85mm.

[0190] Loading speed: The present invention sets two quasi-static compression loading speeds of 2 mm / min and 500 mm / min to study the effect of loading speed on the filling TPMS structure.

[0191] Some of the test results are as follows Figure 3 As shown, Figure 3 The test results of three filled P structures under different filling particle size test conditions are shown in (a) specific energy consumption (SED) (b) residual energy dissipation rate (c) deformation recovery rate (d) energy dissipation rate.

[0192] Step S25: By analyzing the deformation records of the first cycle compression in detail, different configurations of TPMS under the same relative density are selected, and the influence of different filling ratios on the deformation mode of the TPMS structure is studied. The method includes using visual observation technology to check the significant damage types on the surface of the sample, such as surface depressions, matrix material cracks, and structural fractures, so as to reveal the influence of the filling ratio on the structural performance.

[0193] Among them, the influence of filling ratio on deformation mode:

[0194] 0% filling: exhibits significant local thin-wall wrinkles and elastic buckling, is prone to forming deformation bands, and is prone to densification, especially at high compression rates.

[0195] 50% filling: The local presence of sand changes the deformation mode, making the unfilled area exhibit deformation characteristics similar to 0% filling, while the filled area is more stable and the load resistance is significantly improved.

[0196] 100% filling: The complete filling of sand particles inhibits the local buckling of the hole wall, the overall buckling is significant, and the structure exhibits higher stability and load resistance.

[0197] The influence of structure type on deformation mode:

[0198] The D structure has the highest load resistance and delayed elastic buckling characteristics.

[0199] The P structure shows obvious thin-wall folds and "I"-shaped deformation bands.

[0200] The deformation and load resistance of the G structure are between the P structure and the D structure.

[0201] Step S3: Perform a dynamic impact test on the TPMS configuration designed in step S1. The main purpose of the dynamic impact test is to explore how different impact energy levels affect the dynamic response of the specimen and the type of damage caused.

[0202] Step S31: Accurately place the test specimen in step S1 on the rigid plate to ensure stability during the impact process. Through the dual guide rail system, the heavy hammer falls freely and vertically to the surface of the specimen under the action of gravity to apply impact force. A voltage sensor is installed on the top of the punch to capture and record the voltage changes at the contact point between the punch and the specimen during the impact. By converting the voltage data, a curve representing the change of the contact force, displacement, velocity and energy between the punch and the specimen over time is generated, providing key data on the physical behavior of the specimen under low-speed impact. Use a high-speed camera (30,000 fps) to record the deformation process of the specimen to ensure data integrity. Subsequently, the dynamic response of the specimen under different impact energies is analyzed, including deformation, crack generation, and internal damage extension.

[0203] Step S32: Control the initial impact energy by adjusting the mass of the hammer or the height between the hammer and the sample, and perform an impact test. The study used five exponentially increasing impact energies (20J, 40J, 80J, 160J, 300J, 300J is the maximum range of the test machine), and set specific impact energy values ​​in the test. According to the principle of potential energy, the test device accurately controls the impact energy by changing the mass of the falling hammer and the lifting height:

[0204] U=mgH

[0205] Where: H is the height between the falling weight and the sample (m); U is the gravitational potential energy of the falling weight (J); m is the mass of the falling weight (kg); g is the acceleration due to gravity (m / s 2 ).

[0206] During the impact process, the falling of the hammer head is regarded as free fall motion, and the reduced gravitational potential energy is converted into the impact kinetic energy E applied to the sample:

[0207]

[0208] Where: v0 is the initial velocity when the hammer contacts the specimen (m / s).

[0209] High energy impact testing is controlled by adjusting the weight and height of the drop hammer. The test equipment captures the load data when the punch contacts the specimen and calculates the change in the drop hammer velocity over time using the following formula:

[0210]

[0211] Where: v(t) is the speed of the hammer at time t (m / s); when v(t)>0, the punch moves downward; when v(t)<0, the punch rebounds and moves upward; t is time (s); F(t) is the contact force between the hammer and the specimen at time t (N).

[0212] After the specimen is impacted, the absorbed energy of the specimen is converted from the kinetic energy of the punch and calculated by the following formula:

[0213]

[0214] Where: E a ——Energy absorbed by the specimen during the impact process (J). Through this step, the energy absorption capacity and impact resistance of the specimen under different impact energies can be deeply analyzed.

[0215] Step S33: Simulate impact conditions from mild to extreme by applying different levels of impact energy. The selected impact energies are 20J, 40J, 80J, 160J and 300J, respectively, to cover a wide range of possible impact scenarios, so as to more comprehensively evaluate the performance of the filled TPMS structure. In addition to the evaluation indicators of step S23, the present invention also uses the energy absorption formula to calculate the energy absorption ratio of each structure under different impact energies;

[0216]

[0217] Where: E a Indicates the absorbed energy of the specimen, in J; E i It represents the impact energy in J; η is the energy absorption efficiency in %. Some test analysis results are as follows Figure 4 As shown, the energy absorption efficiency of the P structure under dynamic impact test at different energies.

[0218] Step S34: By analyzing the deformation records of the first cycle compression in detail, different configurations of TPMS under the same relative density are selected, and the influence of different filling ratios on the deformation mode of the TPMS structure is studied. The method includes using visual observation techniques to check the significant damage types on the surface of the sample, such as surface depressions, matrix material cracks and structural fractures, so as to reveal the influence of the filling ratio on the structural performance of the TPMS.

[0219] Step S4: Based on the research results of Step 2 and Step 3, the P configuration with the best filling effect and the D structure with the strongest bearing capacity are selected. These two structures are further designed as a two-stage energy absorption structure for the buffer system of the deep-sea lander. The detailed buffer structure is shown in the figure below, which details the configuration and working principle of the two-stage energy absorption structure.

[0220] Step S41: Since the TPMS structure exhibits periodic symmetry in three independent directions, this symmetry can be infinitely reproduced through the repetition of its unit cell. Modeling software can be used to discretize the cylindrical model using a mapping grid, as shown in the figure, and use the TPMS unit distorted by the shape function. Fill it in the mapping grid to form a cylindrical mapping structure. Figure 5Only the circular mapping structure based on the P structure is shown.

[0221] Step S42: and design as Figure 6 The structure shown.

[0222] 1 is a circular mapping structure based on the TPMS filling D structure

[0223] 2 is a circular mapping structure based on the TPMS filling P structure

[0224] Both structures 1 and 2 are made of memory alloy materials, and the deformation of the structure is controlled by activating its thermal resistance effect through power supply. Specifically, when the memory alloy material is powered on, the flow of current causes local heating of the material, causing a phase change, thereby causing the deformation of the structure. This process can accurately control the deformation of structures 1 and 2, and then adjust the response characteristics of the buffer to achieve optimal absorption and distribution of impact force. In this way, the buffer structure can be dynamically adjusted according to different working environments and impact loads, improving its performance under complex conditions.

[0225] The magnetorheological fluid is filled into the structure 1. The magnetorheological fluid is composed of tiny magnetic particles suspended in a base liquid. In the absence of a magnetic field, it exhibits a low resistance state, allowing the liquid to flow freely. When a magnetic field is applied, the magnetic particles quickly align to form a chain structure, significantly increasing the viscosity and resistance of the liquid, thereby changing the flow characteristics of the fluid.

[0226] 3, 4, and 5 are electromagnetic coils, which are used as the source of the magnetic field to control the state change of the magnetorheological fluid to achieve a fast-response dynamic adjustment function.

[0227] 6 and 7 are springs. In view of the slow deformation and recovery efficiency of memory alloy materials and their weak response to rapid impact loads, springs are introduced in this design as auxiliary energy-absorbing elements. The addition of springs can not only share part of the impact load, but also improve the overall dynamic response capability of the system. Under the action of rapid impact loads, the spring effectively absorbs part of the energy through its elastic deformation, thereby reducing the stress concentration of the memory alloy material and extending its service life.

[0228] 8 and 9 are re-compressible soft films, which can effectively prevent the magnetic fluid from overflowing. The film has excellent elasticity and compressibility, and can be deformed under external pressure or impact, but can quickly return to its original shape. This design can not only effectively limit the leakage of magnetic fluid and maintain the stability of magnetic fluid, but also provide additional protection in various working environments, especially in extreme temperature or pressure changes, to ensure the efficient operation and reliability of the magnetic fluid system.

[0229] Figure 10 shows the structural design of the landing legs and base of the lander. The landing legs and base are made of high-strength, lightweight materials, which can provide the necessary cushioning effect during landing and reduce the impact force on the lander. The design of the landing legs takes into account multiple factors, including the diversity of landing surfaces and various environmental conditions that may be encountered during landing (such as air pressure changes, ground hardness, etc.). The base part ensures the stability of the lander when it contacts the ground through precise structural design, and can effectively absorb and disperse the impact force.

[0230] In addition, the installation position of the spring has been optimized to form a synergistic energy absorption mechanism with the structures in step 1 and step 2. In the early stage of impact, the spring responds quickly to reduce the load of the memory alloy material by absorbing energy and distributing the load; in the subsequent energy absorption stage, the memory alloy material gradually recovers to ensure the overall stability and reliability of the energy absorption system. This design significantly improves the impact bearing capacity and recovery efficiency of the energy absorption system, providing a more efficient solution for dealing with complex dynamic loads.

[0231] Description of landing behavior: During the landing process, when the lander touches the ground, the electromagnetic coils of structures 1 and 2 are energized. When subjected to impact loads, structure 1 and the spring are first compressed and deformed. Due to the compression, part of the magnetorheological fluid flows out of structure 1 and enters structure 2. The electromagnetic coil is installed at the bottom of structure 2, and after power is turned on, the magnetorheological fluid continues to play a resistance role, thereby effectively absorbing and alleviating the impact energy. When structure 1 reaches the density point, structure 2 and the spring continue to compress and deform, forming a multi-stage energy absorption effect, further sharing the energy of the impact load.

[0232] When the lander lands stably, the memory alloy materials of structures 1 and 2 are energized and activated, and the electromagnetic coil of structure 2 is turned off. By adjusting the current, the deformation state of structures 1 and 2 is controlled to ensure that the lander remains balanced. In addition, part of the magnetorheological fluid flows back to structure 1, filling it and restoring its function, so that it continues to bear the weight of the lander and maintain stability.

[0233] When the lander floats up, structures 1 and 2 are powered on to restore the initial state, while generating a certain reaction force to assist the lander in floating up from the seabed. During this process, the system can be restored and reused to ensure the efficiency and reliability of the equipment.

[0234] Step S5: Steps S1 to S3: Design and perform filling, static quasi-compression tests, and dynamic impact tests of the TPMS structure. Specifically, it includes optimizing the filling effect of the TPMS structure, performing static compression tests on it to evaluate its bearing capacity, and verifying its impact resistance through dynamic impact tests. These steps provide basic data for designing efficient energy absorption and buffer structures. Step S4: According to the specific application requirements of the deep-sea lander, design a landing buffer structure that meets the requirements. In this step, according to the requirements of different equipment for buffer performance, a suitable design scheme is proposed to ensure the stability and efficiency of the structure.

[0235] Summarize and summarize the design methods and processes in steps S1 to S4 to form a set of systematic design ideas. According to different application scenarios and equipment requirements, further optimize the buffer design to ensure reliable performance and buffering effect under various working conditions.

[0236] The technical solution of the present invention,

[0237] (1) The present invention uses the implicit function of TPMS and 3D modeling software to design three different TPMS structures, and then designs the seal and end cap of the structure to provide conditions for material filling. The TPMS sealing structure is realized by designing thin walls around the structure, and the end cap is interlocked with the structure by interference fit. At the same time, three different filling ratio structures are designed, namely 0%, 50% and 100% filling.

[0238] (2) The present invention conducted 20 cycles of compression tests on the structure using a universal compression testing machine, explored the energy absorption capacity of the filled TPMS structure under quasi-static compression conditions, and compared the differences in deformation mode and energy absorption of three different configurations of TPMS structures under different sand filling ratios. At the same time, single-factor tests of different placement times, filling particles and loading speeds were conducted on the Primitive (P) structures with three filling ratios, further exploring the impact of filling on the performance of the TPMS structure under different quasi-static compression conditions and different size particle filling conditions.

[0239] (3) In the present invention, a series of in-depth tests and analyses were conducted on the filled TPMS structure, especially considering its performance under dynamic impact conditions. First, by designing impact energies of 20J, 40J, 80J, 160J and 300J for the Primitive (P) structure with 0%, 50% and 100% filling ratios, we conducted a series of dynamic impact tests, which are intended to simulate the impact conditions that may be encountered in actual applications. In order to accurately capture the deformation process of the TPMS structure when it is impacted, the present invention uses high-speed camera technology, which can record every moment of material deformation with high resolution, thereby revealing the specific deformation mode of the TPMS structure under dynamic impact. Through the data collected under different impact energies, we obtained the stress-strain curve and time-energy curve of the filled TPMS structure. These curves provide us with a basis for quantitative analysis, allowing us to compare and analyze in detail the energy absorption characteristics and impact resistance of TPMS structures with different filling ratios under dynamic impact conditions. By comparison, we found that the filling ratio has a significant effect on the dynamic response of the TPMS structure, especially in improving its impact resistance and energy absorption efficiency.

[0240] Embodiment 2

[0241] The present invention also provides a deep-sea landing buffer design system based on a filling optimized TPMS structure, the system is used to implement any one of the methods described, the system comprising: a first design module, a static test module, a dynamic test module, a second design module and an optimization module;

[0242] The first design module is used to design and prepare the filling TPMS structure;

[0243] The static test module is used to perform quasi-static compression testing on the filled TPMS structure;

[0244] The dynamic test module is used to perform dynamic impact performance tests on the filled TPMS structure;

[0245] The second design module is used to select a filling TPMS structure that meets the preset requirements and design a buffer system for the deep-sea lander based on the results of the quasi-static compression test and the results of the dynamic impact performance test;

[0246] The optimization module is used to optimize the buffer system of the deep-sea lander according to different application scenarios and equipment requirements.

[0247] In this embodiment, in the first design module, designing and preparing the filling TPMS structure includes:

[0248] Design three different TPMS structures;

[0249] Designing a TPMS sealing structure, wherein the design of the TPMS sealing structure includes: thin-wall design and end cover design;

[0250] Prepare and fill TPMS structure samples;

[0251] preparing filling materials;

[0252] Filling the prepared filling material into the prepared filled TPMS structure sample and performing a repeatability experimental test;

[0253] Among them, three different TPMS structures are designed:

[0254] φ p (x,y,z)=cosx+cosy+cosz=c

[0255] φ G (x,y,z)=cosxsiny+cosysinz+coszsinx=c

[0256] φ D (x,y,z)=sinxsinysinz+cosxinysinz+

[0257] sinxcosysinz+sinxsinycosz=c

[0258] Among them, φ P (x,y,z),φ G (x,y,z),φ D (x, y, z) are the equations of the primitive surface (P), the gyroid surface (G), and the diamond surface (D), respectively. x, y, z are the coordinates in three-dimensional space, describing the geometric position of the TPMS. c is a constant used to describe the value of the level set corresponding to the TPMS surface.

[0259] Among them, the preparation of the filled TPMS structure sample includes: using 3D printing technology to manufacture the TPMS lattice structure and top seal;

[0260] The preparation of the filling material includes: drying the filling material; after drying, storing the filling material in a constant temperature and humidity chamber; further pre-screening the filling material and classifying it into three categories according to particle size: 0.15 mm, 0.65 mm and 0.85 mm.

[0261] In this embodiment, in the static test module, performing a quasi-static compression test on the filled TPMS structure includes:

[0262] Select the testing machine and force sensor range that meet the preset requirements, combine three structural configurations, different rest times, particle sizes and loading speeds, and select three samples for repeated tests;

[0263] Five key indicators were used to analyze the test results and obtain the energy absorption results of three configurations with different filling ratios;

[0264] Analyze the standing time, filler material particle size, and loading speed;

[0265] By analyzing the deformation records of the first cycle compression, different configurations of TPMS with the same relative density are selected, and the influence of different filling ratios on the deformation mode of the TPMS structure is analyzed;

[0266] Among them, the five key indicators include:

[0267] Energy Absorption EA: Among them, S is the displacement of strain, F(s) represents the force corresponding to a certain point in the deformation process, m represents the mass, and SEA represents the specific energy absorption, that is, the energy absorbed per unit mass;

[0268] Specific energy dissipation SED: Where ED is the energy dissipated during the cyclic compression test, and is the area under the hysteresis curve;

[0269] Remaining energy dissipation percentage: Among them, @current cycle indicates the current cycle, and @1st cycle indicates the first cycle;

[0270] Deformation recovery rate; R = (1-ε r )×100%; where ε r is the residual strain, R is the deformation recovery rate;

[0271] Damping characteristics;

[0272] Five key indicators were used to analyze the test results, including: separate comparative analysis of different filling ratios of different configurations, and comprehensive comparative analysis of different filling ratios of different configurations.

[0273] In this embodiment, in the dynamic test module, the dynamic impact performance test of the filled TPMS structure includes:

[0274] The specimen to be tested is placed on a rigid plate, and a heavy hammer is made to fall freely and vertically to the surface of the specimen under the action of gravity through a double rail system to apply impact force, and the voltage change at the contact point between the punch and the specimen during the impact process is captured and recorded. By converting the voltage data, a curve representing the contact force, displacement, velocity and energy between the punch and the specimen over time is generated, and the dynamic response of the specimen under different impact energies is analyzed, wherein the dynamic response includes deformation, crack generation and internal damage extension;

[0275] By adjusting the mass of the hammer or the height between the hammer and the specimen, the initial impact energy is controlled, and the impact test is performed to analyze the energy absorption capacity and impact resistance of the specimen under different impact energies;

[0276] By applying different levels of impact energy to simulate impact conditions from mild to extreme, the energy absorption efficiency of the specimen under different impact energies is analyzed;

[0277] By analyzing the deformation records of the first cycle compression, different configurations of TPMS with the same relative density are selected, and the influence of different filling ratios on the deformation mode of the TPMS structure is analyzed;

[0278] Among them, the initial impact energy is controlled by adjusting the mass of the hammer head or the height between the hammer head and the test piece. The impact test includes:

[0279] During the impact process, the falling of the hammer head is regarded as free fall motion, and the reduced gravitational potential energy is converted into the impact kinetic energy E applied to the specimen:

[0280]

[0281] In the formula, v0 is the initial velocity of the hammer head when it contacts the specimen, and U is the gravitational potential energy of the falling hammer;

[0282] High-energy impact tests are controlled by adjusting the weight and height of the drop hammer; the test equipment captures the load data when the punch contacts the specimen and calculates the change in the drop hammer velocity over time:

[0283]

[0284] Where, v(t) is the speed of the hammer at time t. When v(t)>0, the punch moves downward. When v(t)<0, the punch rebounds and moves upward. t is time. F(t) is the contact force between the hammer and the specimen at time t.

[0285] After the specimen is impacted, the absorbed energy of the specimen is converted from the kinetic energy of the punch:

[0286]

[0287] In the formula, E ais the energy absorbed by the specimen during the impact;

[0288] Among them, the impact conditions ranging from mild to extreme are simulated by applying different levels of impact energy, including:

[0289]

[0290] In the formula, E a Indicates the absorbed energy of the specimen; E i represents impact energy; η is energy absorption efficiency.

[0291] In this embodiment, in the second design module, based on the results of the quasi-static compression test and the results of the dynamic impact performance test, a filling TPMS structure that meets the preset requirements is selected, and the design of the buffer system of the deep-sea lander includes:

[0292] Based on the results of the quasi-static compression test and the results of the dynamic impact performance test, the P configuration with the best filling effect and the D configuration with the strongest load-bearing capacity were selected;

[0293] The P configuration with the best filling effect and the D structure with the strongest bearing capacity are designed as a two-stage energy absorption structure.

[0294] The embodiments described above are only descriptions of the preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A deep sea landing buffer design method based on filling optimization TPMS structure, characterized in that: The method comprises: S1: Design and preparation of filled TPMS structure; S2: quasi-static compression test of the filled TPMS structure; S3: Dynamic impact performance test of the filled TPMS structure; S4: Based on the results of the quasi-static compression test and the dynamic impact performance test, select the filling TPMS structure that meets the preset requirements and design the buffer system of the deep-sea lander; S5: Optimize the buffer system of the deep-sea lander according to different application scenarios and equipment requirements.

2. The method according to claim 1, characterized in that In S1, designing and preparing a filled TPMS structure includes: Design three different TPMS structures; Designing a TPMS sealing structure, wherein the design of the TPMS sealing structure includes: thin-wall design and end cover design; Prepare and fill TPMS structure samples; preparing filling materials; Filling the prepared filling material into the prepared filled TPMS structure sample and performing a repeatability experimental test; Among them, three different TPMS structures are designed: φ p (x,y,z)=cosx+cosy+cosz=c φ G (x,y,z)=cosxsiny+cosysinz+coszsinx=c φ D (x,y,z)=sinxsinz+cossinz+ sinxcosysinz+sinxsinycosz=c Among them, φ P (x,y,z),φ G (x,y,z),φ D (x, y, z) are the equations of the primitive surface (P), the gyroid surface (G), and the diamond surface (D), respectively. x, y, z are the coordinates in three-dimensional space, describing the geometric position of the TPMS. c is a constant used to describe the value of the level set corresponding to the TPMS surface. Among them, preparing the filled TPMS structure sample includes: using 3D printing technology to manufacture the TPMS lattice structure and top seal; The preparation of the filling material includes: drying the filling material; after drying, storing the filling material in a constant temperature and humidity chamber; further pre-screening the filling material and classifying it into three categories according to particle size: 0.15 mm, 0.65 mm and 0.85 mm.

3. The method according to claim 1, characterized in that In S2, performing a quasi-static compression test on the filled TPMS structure includes: Select the testing machine and force sensor range that meet the preset requirements, combine three structural configurations, different rest times, particle sizes and loading speeds, and select three samples for repeated tests; Five key indicators were used to analyze the test results and obtain the energy absorption results of three configurations with different filling ratios; Analyze the standing time, filler material particle size, and loading speed; By analyzing the deformation records of the first cycle compression, different configurations of TPMS with the same relative density are selected, and the influence of different filling ratios on the deformation mode of the TPMS structure is analyzed; Among them, the five key indicators include: Energy Absorption EA: Among them, S is the displacement of strain, F(s) represents the force corresponding to a certain point during the deformation process, m represents the mass, and SEA represents the specific energy absorption, that is, the energy absorbed per unit mass; Specific energy dissipation SED: Where ED is the energy dissipated during the cyclic compression test, and is the area under the hysteresis curve; Remaining energy dissipation percentage: Among them, @current cycle indicates the current cycle, and @1st cycle indicates the first cycle; Deformation recovery rate; R = (1-ε r )×100%; where ε r is the residual strain, R is the deformation recovery rate; Damping characteristics; Five key indicators were used to analyze the test results, including: separate comparative analysis of different filling ratios of different configurations, and comprehensive comparative analysis of different filling ratios of different configurations.

4. The method according to claim 3, characterized in that In S3, the dynamic impact performance test of the filled TPMS structure includes: The specimen to be tested is placed on a rigid plate, and a heavy hammer is made to fall freely and vertically to the surface of the specimen under the action of gravity through a double rail system to apply impact force, and the voltage change at the contact point between the punch and the specimen during the impact process is captured and recorded. By converting the voltage data, a curve representing the contact force, displacement, velocity and energy between the punch and the specimen over time is generated, and the dynamic response of the specimen under different impact energies is analyzed, wherein the dynamic response includes deformation, crack generation and internal damage extension; By adjusting the mass of the hammer or the height between the hammer and the specimen, the initial impact energy is controlled, and the impact test is performed to analyze the energy absorption capacity and impact resistance of the specimen under different impact energies; By applying different levels of impact energy to simulate impact conditions from mild to extreme, the energy absorption efficiency of the specimen under different impact energies is analyzed; By analyzing the deformation records of the first cycle compression, different configurations of TPMS with the same relative density are selected, and the influence of different filling ratios on the deformation mode of the TPMS structure is analyzed; Among them, the initial impact energy is controlled by adjusting the mass of the hammer head or the height between the hammer head and the test piece. The impact test includes: During the impact process, the falling of the hammer head is regarded as free fall motion, and the reduced gravitational potential energy is converted into the impact kinetic energy E applied to the specimen: In the formula, v0 is the initial velocity of the hammer head when it contacts the specimen, and U is the gravitational potential energy of the falling hammer; High-energy impact tests are controlled by adjusting the weight and height of the drop hammer; the test equipment captures the load data when the punch contacts the specimen and calculates the change in the drop hammer velocity over time: Where, v(t) is the speed of the hammer at time t. When v(t)>0, the punch moves downward. When v(t)<0, the punch rebounds and moves upward. t is time. F(t) is the contact force between the hammer and the specimen at time t. After the specimen is impacted, the absorbed energy of the specimen is converted from the kinetic energy of the punch: In the formula, E a is the energy absorbed by the specimen during the impact; Among them, the impact conditions ranging from mild to extreme are simulated by applying different levels of impact energy, including: In the formula, E a Indicates the absorbed energy of the specimen; E i represents impact energy; η is energy absorption efficiency.

5. The method according to claim 1, characterized in that In S4, based on the results of the quasi-static compression test and the results of the dynamic impact performance test, a filling TPMS structure that meets the preset requirements is selected, and the buffer system of the deep-sea lander is designed, including: Based on the results of the quasi-static compression test and the results of the dynamic impact performance test, the P configuration with the best filling effect and the D configuration with the strongest load-bearing capacity were selected; The P configuration with the best filling effect and the D structure with the strongest bearing capacity are designed as a two-stage energy absorption structure.

6. A deep-sea landing buffer design system based on filling optimization TPMS structure, the system is used to implement the method according to any one of claims 1 to 5, characterized in that: The system comprises: a first design module, a static test module, a dynamic test module, a second design module and an optimization module; The first design module is used to design and prepare a filling TPMS structure; The static test module is used to perform a quasi-static compression test on the filled TPMS structure; The dynamic test module is used to perform a dynamic impact performance test on the filled TPMS structure; The second design module is used to select a filling TPMS structure that meets preset requirements and design a buffer system for the deep-sea lander based on the results of the quasi-static compression test and the results of the dynamic impact performance test; The optimization module is used to optimize the buffer system of the deep-sea lander according to different application scenarios and equipment requirements.

7. The system according to claim 6, characterized in that In the first design module, designing and preparing the filled TPMS structure includes: Design three different TPMS structures; Designing a TPMS sealing structure, wherein the design of the TPMS sealing structure includes: thin-wall design and end cover design; Prepare and fill TPMS structure samples; preparing filling materials; Filling the prepared filling material into the prepared filled TPMS structure sample and performing a repeatability experimental test; Among them, three different TPMS structures are designed: φ p (x,y,z)=cosx+cosy+cosz=c φ G (x,y,z)=cosxsiny+cosysinz+coszsinx=c φ D (x,y,z)=sinxsinz+cossinz+ sinxcosysinz+sinxsinycosz=c Among them, φ P (x,y,z),φ G (x,y,z),φ D (x, y, z) are the equations of the primitive surface (P), the gyroid surface (G), and the diamond surface (D), respectively. x, y, z are the coordinates in three-dimensional space, describing the geometric position of the TPMS. c is a constant used to describe the value of the level set corresponding to the TPMS surface. Among them, preparing the filled TPMS structure sample includes: using 3D printing technology to manufacture the TPMS lattice structure and top seal; The preparation of the filling material includes: drying the filling material; after drying, storing the filling material in a constant temperature and humidity chamber; further pre-screening the filling material and classifying it into three categories according to particle size: 0.15 mm, 0.65 mm and 0.85 mm.

8. The system according to claim 6, characterized in that In the static test module, the quasi-static compression test of the filled TPMS structure includes: Select the testing machine and force sensor range that meet the preset requirements, combine three structural configurations, different rest times, particle sizes and loading speeds, and select three samples for repeated tests; Five key indicators were used to analyze the test results and obtain the energy absorption results of three configurations with different filling ratios; Analyze the standing time, filler material particle size, and loading speed; By analyzing the deformation records of the first cycle compression, different configurations of TPMS with the same relative density are selected, and the influence of different filling ratios on the deformation mode of the TPMS structure is analyzed; Among them, the five key indicators include: Energy Absorption EA: Among them, S is the displacement of strain, F(s) represents the force corresponding to a certain point during the deformation process, m represents the mass, and SEA represents the specific energy absorption, that is, the energy absorbed per unit mass; Specific energy dissipation SED: Where ED is the energy dissipated during the cyclic compression test, and is the area under the hysteresis curve; Remaining energy dissipation percentage: Among them, @current cycle indicates the current cycle, and @1st cycle indicates the first cycle; Deformation recovery rate; R = (1-ε r )×100%; where ε r is the residual strain, R is the deformation recovery rate; Damping characteristics; Five key indicators were used to analyze the test results, including: separate comparative analysis of different filling ratios of different configurations, and comprehensive comparative analysis of different filling ratios of different configurations.

9. The system according to claim 8, characterized in that In the dynamic test module, the dynamic impact performance test of the filled TPMS structure includes: The specimen to be tested is placed on a rigid plate, and a heavy hammer is made to fall freely and vertically to the surface of the specimen under the action of gravity through a double rail system to apply impact force, and the voltage change at the contact point between the punch and the specimen during the impact process is captured and recorded. By converting the voltage data, a curve representing the contact force, displacement, velocity and energy between the punch and the specimen over time is generated, and the dynamic response of the specimen under different impact energies is analyzed, wherein the dynamic response includes deformation, crack generation and internal damage extension; By adjusting the mass of the hammer or the height between the hammer and the specimen, the initial impact energy is controlled, and the impact test is performed to analyze the energy absorption capacity and impact resistance of the specimen under different impact energies; By applying different levels of impact energy to simulate impact conditions from mild to extreme, the energy absorption efficiency of the specimen under different impact energies is analyzed; By analyzing the deformation records of the first cycle compression, different configurations of TPMS with the same relative density are selected, and the influence of different filling ratios on the deformation mode of the TPMS structure is analyzed; Among them, the initial impact energy is controlled by adjusting the mass of the hammer head or the height between the hammer head and the test piece. The impact test includes: During the impact process, the falling of the hammer head is regarded as free fall motion, and the reduced gravitational potential energy is converted into the impact kinetic energy E applied to the specimen: In the formula, v0 is the initial velocity of the hammer head when it contacts the specimen, and U is the gravitational potential energy of the falling hammer; High-energy impact tests are controlled by adjusting the weight and height of the drop hammer; the test equipment captures the load data when the punch contacts the specimen and calculates the change in the drop hammer velocity over time: Where, v(t) is the speed of the hammer at time t. When v(t)>0, the punch moves downward. When v(t)<0, the punch rebounds and moves upward. t is time. F(t) is the contact force between the hammer and the specimen at time t. After the specimen is impacted, the absorbed energy of the specimen is converted from the kinetic energy of the punch: In the formula, E a is the energy absorbed by the specimen during the impact; Among them, the impact conditions ranging from mild to extreme are simulated by applying different levels of impact energy, including: In the formula, E a Indicates the absorbed energy of the specimen; E i represents impact energy; η is energy absorption efficiency.

10. The system according to claim 6, characterized in that In the second design module, based on the results of the quasi-static compression test and the results of the dynamic impact performance test, a filling TPMS structure that meets the preset requirements is selected, and the buffer system of the deep-sea lander is designed, including: Based on the results of the quasi-static compression test and the results of the dynamic impact performance test, the P configuration with the best filling effect and the D configuration with the strongest load-bearing capacity were selected; The P configuration with the best filling effect and the D structure with the strongest bearing capacity are designed as a two-stage energy absorption structure.

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