A design method of a crash cushion, the crash cushion and a crash cushion vehicle

Abstract

The present application relates to the technical field of road traffic safety protection equipment, and particularly relates to a design method of a crash cushion, the crash cushion and a crash cushion vehicle. The design method comprises the following steps: determining a plurality of core collision conditions and design parameters; determining target design energy absorption amounts under the plurality of core collision conditions; designing energy absorption modules and calculating total energy absorption of the energy absorption modules; based on the target design energy absorption amounts under the plurality of core collision conditions, checking the total energy absorption of the energy absorption modules, and outputting the design parameters of the energy absorption modules after the checking condition is met. The present application provides a parameterized design method of the crash cushion, which starts from the regulation conditions, determines the energy absorption requirements through quantitative calculation, and then guides the design of the honeycomb structure and the gradient energy absorption structure, so that the accurate quantitative calibration of the energy absorption requirements and the parameterized design of the gradient energy absorption structure are realized, and the systematicness and repeatability of the design process are improved.

Description

Technical Field

[0001] This invention relates to the field of road traffic safety protection equipment technology, specifically to a design method for a crash buffer pad, a crash buffer pad, and a crash buffer vehicle. Background Technology

[0002] With the continuous improvement of mechanization in the maintenance of highways, urban expressways, and ordinary trunk roads, crash buffer vehicles have become key equipment for rear protection in mobile work areas. This equipment is typically deployed upstream of the construction area or accident handling area. When an out-of-control vehicle crashes from behind, the crash buffer pads at the rear absorb the collision energy through gradual crushing and deformation, effectively reducing the risk of secondary injuries to personnel, equipment, and road facilities in front.

[0003] However, existing crash cushion designs still generally have the following shortcomings: First, the design process relies heavily on experience iteration and structural trial and error, lacking a unified quantitative method to deduce energy absorption requirements from regulatory conditions and target test conditions, resulting in an unclear correspondence between energy-absorbing material configuration and boundary conditions; Second, some designs only focus on the total amount of material and do not fully consider the anisotropic crushing characteristics of honeycomb aluminum in different directions, making it difficult to balance energy absorption efficiency and crushing stability.

[0004] Furthermore, in high-speed collisions, the crash buffer must effectively absorb the impact energy of a rear-impacting vehicle while controlling the occupant deceleration within permissible limits and ensuring that the crash buffer's sliding distance does not exceed the required safe operating distance. Simply increasing the thickness of the energy-absorbing material is insufficient: if the initial stiffness is too high, although it can increase the total energy absorption, it can easily lead to excessively high peak deceleration in the initial stage of the collision; if the initial stiffness is too low, it will result in excessively soft front-end crushing, excessive dynamic deflection, and may even cause subsequent structures to delay participating in energy absorption.

[0005] Therefore, there is an urgent need to propose a design method for anti-collision buffer pads that starts from regulatory operating conditions, determines energy absorption requirements through quantitative calculations, and then guides the design of honeycomb configurations and gradient energy absorption structures, in order to solve the problem that existing experience-based designs cannot balance energy absorption efficiency and occupant safety. Summary of the Invention

[0006] The purpose of this invention is to provide a design method for a crash buffer pad, a crash buffer pad, and a crash buffer vehicle, in order to solve the problems in the prior art where the energy absorption material configuration and the boundary conditions correspond unclearly due to the lack of a path to quantitatively deduce energy absorption requirements from regulatory operating conditions, and where energy absorption efficiency and crushing stability are difficult to balance due to insufficient consideration of the outward crushing characteristics of honeycomb aluminum and the lack of gradient configuration.

[0007] The first aspect of this invention provides a method for designing an anti-collision buffer pad, comprising the following steps: S1. Determine the various core collision conditions and the corresponding design parameters for each core collision condition; S2. Based on the design parameters corresponding to each core collision condition, calculate the theoretical maximum energy absorption of the anti-collision buffer pad under the assumption of a completely inelastic collision under each core collision condition, and the theoretical minimum energy absorption under the constraints of the maximum allowable slip distance and the maximum allowable occupant deceleration, so as to determine the target design energy absorption under various core collision conditions. S3. Design an energy absorption module, which consists of multiple layers of honeycomb block-shaped energy absorption units. The effective energy absorption of each layer of honeycomb block-shaped energy absorption units is shown below: , In the formula, This is the layer index for the honeycomb block energy-absorbing unit. For the first The effective energy absorption of layered honeycomb block-shaped energy-absorbing units For the first The effective energy absorption efficiency coefficient of the layered honeycomb block energy absorption unit. For the first The average plateau stress of the layered honeycomb block energy-absorbing unit, For the first The effective cross-sectional area of ​​the layered honeycomb block energy-absorbing unit, which is perpendicular to the main impact direction of the rear-impacting vehicle and actually participates in load transfer, is subjected to pressure. For the first Effective crushing stroke of layered honeycomb block energy-absorbing units; S4. Based on the effective energy absorption of each layer of honeycomb block energy absorption unit, calculate the total energy absorption of the energy absorption module, as shown below: , In the formula, n is the total number of layers in the honeycomb block energy-absorbing unit. This represents the total energy absorbed by the energy absorption module. S5. Based on the target design energy absorption under multiple core collision conditions, check the total energy absorption of the energy absorption module. If the total energy absorption of the energy absorption module is greater than the target design energy absorption under multiple core collision conditions, and the maximum allowable occupant deceleration and crush stability meet the preset requirements, output the design parameters of the energy absorption module; otherwise, return to step S3 to redesign the energy absorption module.

[0008] Preferably, multiple core collision conditions are determined based on the target protection level, applicable road scenarios, and regulatory test conditions; and the design parameters corresponding to each core collision condition are determined based on the target protection level, applicable road scenarios, relevant road traffic safety protection regulations, and technical standards. The design parameters for each core collision scenario include the mass of the rear-impact vehicle, the collision speed of the rear-impact vehicle, the mass of the crash buffer vehicle, the maximum permissible occupant deceleration, the maximum permissible slip distance, and the road surface adhesion coefficient. The design parameters of the energy absorption module include the total number of layers of honeycomb block energy absorption units, the nominal thickness of the honeycomb cell wall, the side length, thickness, width, length, effective energy absorption efficiency coefficient, effective crushing stroke, yield stress of the honeycomb substrate, equivalent compression rate, characteristic strain rate parameter, strain rate sensitivity index, equivalent density, and substrate density of each layer of honeycomb block energy absorption unit. The standard for both the maximum allowable occupant deceleration and crush stability to meet the preset requirements is as follows: the maximum allowable occupant deceleration is less than the preset safety threshold; at the same time, in the compression stability simulation, the overall compression process of the energy absorption module is stable, exhibits gradual and uniform crushing, and no obvious instability phenomenon is observed. The design method of the anti-collision buffer pad is applicable to all speed conditions from 60km / h to 120km / h.

[0009] Preferably, step S2 specifically includes: S21. If the rear-impacting vehicle is the main kinetic energy input, the total kinetic energy of the system before the collision in each core collision scenario is as follows: , In the formula, j is the index of the number of core collision conditions. Let be the total kinetic energy of the system before the collision in the j-th core collision scenario. Let be the mass of the vehicle in a rear-end collision under the j-th core collision scenario. Let be the rearward collision speed of the vehicle in the j-th core collision scenario. S22. Calculate the theoretical maximum energy absorption of the anti-collision buffer pad under the assumption of a completely inelastic collision under each core collision condition. Specifically: S221. Based on the law of conservation of momentum, calculate the common velocity of the front and rear vehicles after a perfectly inelastic collision under each core collision condition, as shown below: , In the formula, Let be the common velocity of the front and rear vehicles after a completely inelastic collision under the j-th core collision condition. The mass of the crash buffer vehicle for the j-th core collision condition; S222. Based on the common velocity of the front and rear vehicles after a fully inelastic collision under each core collision condition, calculate the post-collision system kinetic energy under the fully inelastic collision condition for each core collision condition, as shown below: , In the formula, Let be the post-collision system kinetic energy under the completely inelastic collision condition of the j-th core collision condition; S223. Based on the total kinetic energy of the system before collision under each core collision condition and the kinetic energy of the system after collision under the completely inelastic collision condition, calculate the theoretical maximum energy absorption of the anti-collision buffer pad under the assumption of a completely inelastic collision under each core collision condition, as shown below: , In the formula, The theoretical maximum energy absorption of the anti-collision buffer pad under the assumption of a completely inelastic collision under the j-th core collision condition; S23. Calculate the theoretical minimum energy absorption under the constraints of the maximum allowable slip distance and the maximum allowable occupant deceleration for each core collision condition. Specifically: S231. Based on the maximum permissible occupant deceleration for each core collision scenario, calculate the limit deceleration distance for a rear-impact vehicle to decelerate from the collision speed to zero under each core collision scenario, as shown below: , In the formula, Let be the limit deceleration distance for a rear-impact vehicle to decelerate from its collision velocity to zero under the j-th core collision condition. Let be the maximum permissible occupant deceleration for the j-th core collision scenario; S232. Based on the maximum permissible slip distance, road surface adhesion coefficient, and the ultimate deceleration distance corresponding to the rear-impact vehicle's deceleration from the collision speed to zero for each core collision condition, calculate the energy dissipated by the crash buffer vehicle through tire-road friction within the maximum permissible slip distance, and the energy dissipated by the rear-impact vehicle through tire-road friction within the ultimate deceleration distance. The sum of these two values ​​is taken as the permissible frictional dissipation energy for each core collision condition, as shown below: , In the formula, Let the allowable frictional dissipation energy be for the j-th core collision condition. Let be the road surface adhesion coefficient for the j-th core collision condition. The gravitational acceleration of a vehicle in a rear-end collision. Let be the maximum permissible slip distance for the j-th core collision condition; S233. Based on the total kinetic energy of the system before the collision and the allowable frictional dissipation energy under each core collision condition, calculate the theoretical minimum energy absorption under the constraints of the maximum allowable slip distance and the maximum allowable occupant deceleration, as shown below: , In the formula, The theoretical minimum energy absorption under the constraints of the maximum allowable slip distance and the maximum allowable occupant deceleration under the j-th core collision condition; S24. Based on the theoretical maximum energy absorption of the anti-collision buffer pad under the assumption of a completely inelastic collision under various core collision conditions, and the theoretical minimum energy absorption under the constraints of the maximum allowable slip distance and the maximum allowable occupant deceleration, the target design energy absorption under various core collision conditions is determined as follows: , In the formula, Energy absorption is designed for the target under various core collision conditions, where J is the total number of core collision conditions.

[0010] Preferably, when the allowable frictional dissipation energy is greater than or equal to the total kinetic energy of the system before the collision, the anti-collision buffer pad no longer needs to provide additional minimum energy absorption from the perspective of satisfying the sliding distance and occupant deceleration constraints. The theoretical minimum energy absorption under the corresponding working condition that satisfies the allowable maximum sliding distance and allowable maximum occupant deceleration constraints is taken as 0.

[0011] Preferably, the multi-layer honeycomb block energy-absorbing units are arranged starting from the rearward impact surface of the vehicle and distributed along the main impact direction of the rearward impact vehicle. The effective energy absorption of the next layer of honeycomb block energy-absorbing units is greater than that of the previous layer of honeycomb block energy-absorbing units, thus forming a gradient energy-absorbing structure that is softer in the front, more stable in the middle, and stronger in the rear along the main impact direction of the rearward impact vehicle. The energy absorption module also includes multiple partitions, each partition being disposed between two adjacent honeycomb block energy absorption units, at the beginning of the first honeycomb block energy absorption unit, and at the end of the last honeycomb block energy absorption unit, to form multiple compartments for accommodating each layer of honeycomb block energy absorption units. Each layer of honeycomb block energy-absorbing unit is an integral block honeycomb aluminum structure, including multiple honeycomb cells with a regular hexagonal cross-section; multiple honeycomb cells are periodically arranged in a plane perpendicular to the honeycomb hole axis, adjacent honeycomb cells share a cell wall and extend through the direction of the honeycomb hole axis; the extension direction of the honeycomb cell holes of each layer of honeycomb block energy-absorbing unit is in the same direction as the impact load. The width, thickness, yield stress of the honeycomb substrate, characteristic strain rate parameters, strain rate sensitivity index, and substrate density of each layer of honeycomb block energy-absorbing unit are all the same; the cell wall thickness-to-length ratio of the subsequent layer of honeycomb block energy-absorbing unit is greater than that of the previous layer of honeycomb block energy-absorbing unit, that is, the cell wall thickness-to-length ratio of each layer of honeycomb block energy-absorbing unit increases stepwise along the crushing direction, wherein the cell wall thickness-to-length ratio is the ratio of the nominal thickness of the honeycomb cell wall to the side length of the honeycomb cell of that layer of honeycomb block energy-absorbing unit.

[0012] Preferably, the effective energy absorption efficiency coefficient of each layer of honeycomb block energy absorption unit is obtained through experimental calibration or simulation calibration, and is an empirically determined coefficient; the effective energy absorption efficiency coefficient of the next layer of honeycomb block energy absorption unit is greater than that of the previous layer of honeycomb block energy absorption unit, that is, the effective energy absorption efficiency coefficient of each layer of honeycomb block energy absorption unit increases in a stepwise manner along the crushing direction. The average plateau stress of each layer of honeycomb block energy-absorbing unit was obtained through material testing, honeycomb component compression testing, finite element simulation, or theoretical calculation. Furthermore, considering the strain rate strengthening effect of the honeycomb substrate during dynamic impact, the average plateau stress of each layer of honeycomb block energy-absorbing unit is as follows: , In the formula, For the first Yield stress of the honeycomb substrate of the layered honeycomb block energy-absorbing unit; For the first The nominal thickness of the cell wall of the layered honeycomb block energy-absorbing unit, in mm; For the first The side length of the cell in the layered honeycomb block energy-absorbing unit, in mm; For the first The equivalent compression velocity of the layered honeycomb block energy-absorbing unit during major crushing, in mm / s; This is a characteristic strain rate parameter for honeycomb substrates, used to characterize the strain rate scale corresponding to significant dynamic strengthening of the material, in units of... ; is the strain rate sensitivity index of the honeycomb substrate, used to characterize the nonlinearity of the increase in platform stress with increasing equivalent compressive strain rate, and is a dimensionless parameter; The effective cross-sectional area of ​​each layer of honeycomb block energy-absorbing unit, which is perpendicular to the main impact direction of a rear-impacting vehicle and actually participates in load transfer, is calculated as follows: , In the formula, For the first The width of the layered honeycomb block energy-absorbing unit, For the first The thickness of the layered honeycomb block energy-absorbing unit; The effective crushing stroke of each layer of honeycomb block energy-absorbing unit is calculated using the following formula: , , In the formula, For the first The length of the layered honeycomb block energy-absorbing unit, For the first Densification strain of layered honeycomb block energy-absorbing units; For the first The equivalent density of layered honeycomb block energy-absorbing units, in kg / m³. 3 ; The density of the substrate for the honeycomb block energy-absorbing unit is expressed in kg / m³. 3 ; For the first The relative density of layered honeycomb block-shaped energy-absorbing units, .

[0013] A second aspect of the present invention provides a collision buffer pad, obtained using the aforementioned collision buffer pad design method. The collision buffer pad includes an energy-absorbing module and a skin covering the energy-absorbing module, wherein: The energy absorption module consists of a first buffer zone and a second buffer zone arranged sequentially along the main impact direction of the rearward-impacting vehicle, and the first buffer zone and the second buffer zone are connected by a first flipping connection mechanism. Both the first and second buffer zones are arranged with the rearward impact surface of the vehicle as the starting point, and multiple layers of honeycomb block-shaped energy-absorbing units are distributed along the main impact direction of the rearward-impacting vehicle. Within the same buffer zone, the effective energy absorption of the next layer of honeycomb block energy-absorbing units is greater than that of the previous layer of honeycomb block energy-absorbing units; at the same time, the effective energy absorption of the first layer of honeycomb block energy-absorbing units in the second buffer zone is greater than that of the last layer of honeycomb block energy-absorbing units in the first buffer zone.

[0014] Preferably, the cell wall thickness-to-length ratio of the first layer of honeycomb block energy-absorbing units in the second buffer zone is greater than the cell wall thickness-to-length ratio of the last layer of honeycomb block energy-absorbing units in the first buffer zone. All honeycomb block energy-absorbing units in each buffer zone have the same width and thickness; the lengths of honeycomb block energy-absorbing units in each layer within the same buffer zone are equal, while the lengths of honeycomb block energy-absorbing units in different buffer zones are not equal. Each buffer zone has partitions between adjacent honeycomb block energy-absorbing units, at the beginning of the first honeycomb block energy-absorbing unit, and at the end of the last honeycomb block energy-absorbing unit. The first buffer zone and the second buffer zone are connected by a first flipping connection mechanism. The first flipping connection mechanism is used to support the first buffer zone to flip between the 0° working state and the 90° passage state relative to the second buffer zone. When the first buffer zone switches from the 0° working state to the 90° passage state, the first buffer zone flips upward around the first flipping connection mechanism. The anti-collision buffer pad also includes a guide portion disposed on the impact end face of the first buffer zone. The guide portion is a trapezoidal block that is narrow at the front end and wide at the rear end. Its wide end is fixed to the impact end face of the first buffer zone, and its narrow end faces the direction of the rearward impact vehicle. The first and second buffer zones are each independently covered by a skin, while the guide section and the first buffer zone are integrally covered by a skin.

[0015] A third aspect of the present invention provides a crash buffer vehicle having the aforementioned crash buffer pad, wherein the crash buffer pad is connected to the bottom of the vehicle body via a second flip-connecting mechanism.

[0016] Preferably, the second buffer zone of the anti-collision buffer pad is connected to the bottom of the vehicle body through a second flip-connecting mechanism. The second flip-connecting mechanism is used to support the second buffer zone to flip between the 0° working state and the 90° passing state relative to the vehicle body. When the second buffer zone switches from the 0° working state to the 90° passing state, the second buffer zone flips upward around the second flip-connecting mechanism. In the 0° operating state, the first buffer zone and the second buffer zone are arranged collinearly in the horizontal direction, and the longitudinal axis of the anti-collision buffer pad is parallel to the road surface; at the same time, in the 0° operating state, the ground clearance between the bottom surface of the anti-collision buffer pad and the road surface is 200mm. The rear of the crash buffer vehicle is detachably equipped with a support bracket shaped like a "bench". When both the first buffer zone and the second buffer zone are flipped to the 90° passage state, the first buffer zone is flipped upward 90° around the first flipping connecting mechanism and stacked on top of the second buffer zone and the vehicle body and in contact with the support bracket. The support bracket provides vertical support to the first buffer zone. The sum of the lengths of all the honeycomb block energy-absorbing units in the first buffer zone is less than the length of the crash buffer vehicle's cargo compartment; the width of each honeycomb block energy-absorbing unit is less than the width of the crash buffer vehicle's cargo compartment.

[0017] Compared with the prior art, the present invention has the following beneficial effects: 1. This invention incorporates deceleration constraints and slip distance limits as boundary conditions for calculating energy absorption requirements into the same design framework, thereby establishing a quantifiable relationship between boundary constraints and design objectives. This avoids the drawbacks of isolated verification and repeated iterations of various constraints, improves the systematicness and repeatability of the design process, and provides a verifiable and traceable design basis for the engineering development of anti-collision buffer pads.

[0018] 2. Starting from the regulatory test conditions, this invention establishes a completely inelastic collision model based on the laws of conservation of momentum and energy, quantitatively calculates the theoretical maximum and minimum energy absorption of the crash buffer pad, and determines the target design energy absorption based on this. This transforms the design input of the crash buffer pad from empirical values ​​to quantitative boundaries with clear physical meaning, ensuring that the designed crash buffer pad still has sufficient energy absorption capacity under the most unfavorable collision conditions. This overcomes the shortcomings of existing technologies, such as the difficulty in accurately calculating energy absorption requirements and the lack of clear design objectives.

[0019] 3. This invention strictly aligns the axial direction of the honeycomb cells with the main impact direction of a rear-impacting vehicle, ensuring that the honeycomb material always undergoes crushing deformation along the out-of-plane direction where its energy absorption efficiency is highest during the collision. This avoids inefficient failure modes such as lateral shearing or in-plane bending caused by anisotropic characteristics. Simultaneously, multiple layers of energy-absorbing units are arranged layer by layer along the main impact direction of the rear-impacting vehicle, with the effective energy absorption of each subsequent layer being greater than that of the preceding layer. This forms a gradient energy absorption path that increases progressively from front to back, ensuring that the buffer pad crushes progressively from front to back. This avoids the decrease in energy absorption efficiency caused by premature local compaction and the problems of excessive peak deceleration or insufficient crushing stroke caused by excessively large or small initial stiffness. It achieves smooth control of occupant deceleration throughout the collision process, obtaining higher effective energy absorption efficiency and a more stable crushing mode within a limited space.

[0020] 4. This invention incorporates the calculation of energy absorption demand, parameterized configuration of cellular configuration, gradient energy absorption structure design, and total energy absorption constraint verification into the same design process, forming a complete design closed loop that is repeatable, verifiable, and implementable, and has clear engineering feasibility. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a flowchart illustrating a design method for an anti-collision buffer pad according to an embodiment of the present invention; Figure 2 A schematic diagram of the frontal collision test in condition 1-3 of the T / CECS G:E35-04—2024 standard provided for embodiments of the present invention; Figure 3 A schematic diagram of the oblique impact test in condition 4 of the T / CECS G:E35-04—2024 standard provided in this embodiment of the invention; Figure 4 This is a schematic diagram of the structure of a single-layer honeycomb block energy-absorbing unit provided in an embodiment of the present invention; Figure 5 A schematic diagram of the cell geometry parameters of a single-layer honeycomb block energy-absorbing unit provided in an embodiment of the present invention; Figure 6 This is a schematic diagram of the effective cross-sectional area of ​​a single-layer honeycomb block energy-absorbing unit under pressure, provided in an embodiment of the present invention. Figure 7This is a schematic diagram of the effective crushing stroke of a single-layer honeycomb block energy-absorbing unit provided in an embodiment of the present invention, wherein... Figure 7 Figure a shows a top view of a single-layer honeycomb block energy-absorbing unit before it collapses. Figure 7 Figure b is a top view of a single-layer honeycomb block energy-absorbing unit after it has been crushed. Figure 8 This is a schematic diagram of the structure of the anti-collision buffer pad provided in an embodiment of the present invention; Figure 9 This is a schematic diagram of the energy absorption module provided in an embodiment of the present invention; Figure 10 This is a schematic diagram of the anti-collision buffer pad provided in the embodiment of the present invention in the 0° operating state; Figure 11 This is a schematic diagram of the anti-collision buffer pad provided in an embodiment of the present invention in a 90° passage state; Figure 12 A schematic diagram illustrating the deployment process of the anti-collision buffer pad provided in this embodiment of the invention, showing the switching from a 90° passage state to a 0° working state. Figure 13 A schematic diagram of the recycling process for the anti-collision buffer pad, which is switched from a 0° working state to a 90° passage state, as provided in an embodiment of the present invention. Figure 14 A schematic diagram of a finite element model of a vehicle involved in a rear-end collision, provided in an embodiment of the present invention; Figure 15 A graph showing the B-pillar acceleration of a vehicle in a rear-end collision at 120 km / h, provided for an embodiment of the present invention. Figure 16 The diagram shows the system energy conversion curve in the collision simulation experiment of the anti-collision buffer vehicle provided in the embodiment of the present invention. Detailed Implementation

[0023] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. The terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. Furthermore, unless otherwise explicitly specified and limited, the terms "installed," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention in conjunction with the specific circumstances.

[0025] like Figure 1 As shown, the first aspect of the present invention provides a design method for a crash buffer pad, applicable to all speed conditions from 60km / h to 120km / h, comprising the following steps: S1. Determine the various core collision conditions and the corresponding design parameters for each core collision condition.

[0026] In this application, multiple core collision conditions are determined based on the target protection level, applicable road scenarios, and regulatory test conditions. The design parameters corresponding to each core collision condition are determined based on the target protection level, applicable road scenarios, relevant road traffic safety protection regulations and technical standards. The regulatory test conditions include at least one of the test level, collision speed, collision angle, and offset specified in the MASH-2016 or T / CECS G:E35-04—2024 standards.

[0027] In this application, the design parameters for each core collision condition include the mass of the rear-impact vehicle, the collision speed of the rear-impact vehicle, the mass of the crash buffer vehicle, the maximum permissible occupant deceleration, the maximum permissible slip distance, and the road surface adhesion coefficient.

[0028] It should be noted that the evaluation dimensions of the MASH-2016 standard are not limited to the structural failure determination of the collision avoidance device, but rather construct a multi-dimensional comprehensive evaluation system covering structural integrity, occupant injury risk, and vehicle dynamic response. On the one hand, the standard explicitly requires that the collision avoidance device maintain stable energy absorption performance under frontal, offset, and angled collision conditions. On the other hand, it strictly controls the impact load transmitted to the passenger compartment by setting quantitative indicators such as occupant impact velocity (OIV) ≤ 12.2 m / s and occupant ridedown acceleration (ORA) ≤ 20.49g, thereby reducing the probability of serious injury to occupants. In addition, the standard also includes post-collision vehicle attitude stability, trajectory controllability, risk of hazardous debris scattering, and forward slip distance in the assessment scope to avoid secondary threats to personnel and equipment in the construction area. For different collision speeds and test severity, the MASH-2016 standard divides the testing of collision buffer devices (TMAs) into multiple levels. Among them, TL-1, TL-2, and TL-3 correspond to three typical working conditions: low speed, medium speed, and high speed, respectively. The standard collision speeds specified for these three typical working conditions are 50km / h, 70km / h, and 100km / h, respectively, which can comprehensively cover most common rear-end collision scenarios in road construction and maintenance. For specific parameters, please refer to Table 1.

[0029]

[0030] Based on long-term practice and reference to advanced international standards, my country's Traction Array (TMA) standard system has undergone a leapfrog upgrade, relying on a number of the latest independent standards such as T / CECS G-2024. This new system not only completely fills the gap in the domestic TMA product independent grading system, but also proposes a series of high-requirement hard indicators that are tailored to the complex working conditions of road maintenance in my country.

[0031] According to the relevant requirements of the "Safety Performance Evaluation Standard for Road Vehicle-Mounted Buffer Pads" (T / CECS G:E35-04—2024), all crash buffer devices officially installed on highway work buffer vehicles must pass a complete real-vehicle crash test. The highest level, Class V protection, requires full performance verification under four stringent crash conditions to ensure consistent energy absorption performance under impact scenarios at different angles and directions. To accurately represent the actual energy absorption performance of the crash buffer device under multi-angle and multi-directional collisions, and to minimize the interference of irrelevant variables such as vehicle differences on the test results, the standard clearly stipulates that all crash conditions must be completed using the same unmodified rear-end collision vehicle of the same model. Specific parameters and test diagrams for all crash conditions can be found in Table 2. Figure 2-3 During the test, the collision position deviation under various working conditions must be controlled within 0.1m, and the accuracy of the measuring instrument used to measure the collision position must not be less than 0.05m.

[0032]

[0033] During the test, the crash buffer vehicle must maintain its braking state with the handbrake engaged, and the front wheels must remain in a centered, forward-facing position, with permissible directional deviation controlled within ±1.5°. Rear-impact vehicles must possess valid road permits, and their appearance, structure, and all functional components must be intact and functional. No targeted modifications are permitted throughout the test. The vehicle must be less than 10 years old, and its overall vehicle parameters must fully represent the typical technical condition of the vast majority of in-use motor vehicles currently operating on domestic roads. The final collision performance of the crash buffer device must fully comply with all technical requirements listed in Table 3.

[0034]

[0035] In this embodiment, based on the MASH-2016 standard and the "Safety Performance Evaluation Standard for Road Vehicle-Mounted Buffer Pads," four core collision scenarios are determined, with specific parameters shown in Table 4. In this embodiment, a 120K-level crash buffer vehicle is used as the target. The rear-impact vehicle mass is taken as 1100–2270 kg, the rear-impact vehicle speed as 120 km / h, the crash buffer vehicle mass as 12–14 t, the maximum permissible occupant deceleration as 20.49 g, the maximum permissible slip distance as 10 m, and t as the collision time. Following the standard collision time of 0.2–0.3 seconds, 0.2 seconds is used as the calculation value for maximum acceleration. To cover road surface adhesion under different weather conditions, the road surface adhesion coefficient is set according to the weather conditions: 0.6 for sunny days, 0.4 for rainy days, and 0.28 for snowy days.

[0036]

[0037] S2. Based on the design parameters corresponding to each core collision condition, calculate the theoretical maximum energy absorption of the anti-collision buffer pad under the assumption of a completely inelastic collision, and the theoretical minimum energy absorption under the constraints of the maximum allowable slip distance and the maximum allowable occupant deceleration, so as to determine the target design energy absorption under various core collision conditions.

[0038] In this application, step S2 specifically includes: S21. If the rear-impacting vehicle is the main kinetic energy input, the total kinetic energy of the system before the collision in each core collision scenario is as follows: , In the formula, j is the index of the number of core collision conditions. Let be the total kinetic energy of the system before the collision in the j-th core collision scenario. Let be the mass of the vehicle in a rear-end collision under the j-th core collision scenario. Let be the rearward collision speed of the vehicle in the j-th core collision scenario.

[0039] S22. Calculate the theoretical maximum energy absorption of the anti-collision buffer pad under the assumption of a completely inelastic collision under each core collision condition. Specifically: S221. Based on the law of conservation of momentum, calculate the common velocity of the front and rear vehicles after a perfectly inelastic collision under each core collision condition, as shown below: , In the formula, Let be the common velocity of the front and rear vehicles after a completely inelastic collision under the j-th core collision condition. Let be the mass of the crash buffer vehicle for the j-th core collision scenario.

[0040] S222. Based on the common velocity of the front and rear vehicles after a fully inelastic collision under each core collision condition, calculate the post-collision system kinetic energy under the fully inelastic collision condition for each core collision condition, as shown below: , In the formula, Let be the post-collision system kinetic energy under the completely inelastic collision condition of the j-th core collision condition.

[0041] S223. Based on the total kinetic energy of the system before collision under each core collision condition and the kinetic energy of the system after collision under the completely inelastic collision condition, calculate the theoretical maximum energy absorption of the anti-collision buffer pad under the assumption of a completely inelastic collision under each core collision condition, as shown below: , In the formula, This represents the theoretical maximum energy absorption of the anti-collision buffer pad under the assumption of a completely inelastic collision in the j-th core collision condition.

[0042] S23. Calculate the theoretical minimum energy absorption under the constraints of the maximum allowable slip distance and the maximum allowable occupant deceleration for each core collision condition. Specifically: S231. Based on the maximum permissible occupant deceleration for each core collision scenario, calculate the limit deceleration distance for a rear-impact vehicle to decelerate from the collision speed to zero under each core collision scenario, as shown below: , In the formula, Let be the limit deceleration distance for a rear-impact vehicle to decelerate from its collision velocity to zero under the j-th core collision condition. Let be the maximum permissible occupant deceleration for the j-th core collision scenario.

[0043] S232. Based on the maximum permissible slip distance, road surface adhesion coefficient, and the ultimate deceleration distance corresponding to the rear-impact vehicle's deceleration from the collision speed to zero for each core collision condition, calculate the energy dissipated by the crash buffer vehicle through tire-road friction within the maximum permissible slip distance, and the energy dissipated by the rear-impact vehicle through tire-road friction within the ultimate deceleration distance. The sum of these two values ​​is taken as the permissible frictional dissipation energy for each core collision condition, as shown below: , In the formula, Let the allowable frictional dissipation energy be for the j-th core collision condition. Let be the road surface adhesion coefficient for the j-th core collision condition. The gravitational acceleration of a vehicle in a rear-end collision. Let be the maximum permissible slip distance for the j-th core collision condition.

[0044] In the embodiments of this application, m / s 2 .

[0045] S233. Based on the total kinetic energy of the system before the collision and the allowable frictional dissipation energy under each core collision condition, calculate the theoretical minimum energy absorption under the constraints of the maximum allowable slip distance and the maximum allowable occupant deceleration, as shown below: , In the formula, Theoretical minimum energy absorption under the constraints of maximum allowable slip distance and maximum allowable occupant deceleration in the j-th core collision condition.

[0046] S24. Based on the theoretical maximum energy absorption of the anti-collision buffer pad under the assumption of a completely inelastic collision under various core collision conditions, and the theoretical minimum energy absorption under the constraints of the maximum allowable slip distance and the maximum allowable occupant deceleration, the target design energy absorption under various core collision conditions is determined as follows: , In the formula, Energy absorption is designed for the target under various core collision conditions, where J is the total number of core collision conditions.

[0047] It should be noted that the determination of the target energy absorption in this application is not a simple value for the energy absorption result under a single working condition, but rather a boundary-oriented design of the energy absorption capacity of the crash buffer pad. Specifically, the theoretical maximum energy absorption is the upper limit of the most unfavorable energy input that the buffer structure can bear under the assumption of a completely inelastic collision, used to ensure that the buffer pad has energy absorption reserves to cover extreme collision conditions. The theoretical minimum energy absorption is derived by inversely from the maximum allowable slip distance and the maximum allowable occupant deceleration, used to ensure that the buffering process meets vehicle motion control and occupant safety constraints. These two correspond to the "upper limit of energy input" and the "lower limit of safety performance," respectively. Their constraint sources and control objectives are different, and they are complementary rather than substitutable. Therefore, this application uses the larger of the two values ​​as the target energy absorption design, which ensures that the crash buffer pad simultaneously meets the requirements for covering the most unfavorable collision energy and the slip-deceleration safety constraints, while also reserving necessary safety margins for engineering uncertainties such as material performance dispersion, manufacturing and assembly errors, changes in road surface adhesion, and offset collisions. This effectively improves the reliability, adaptability, and safety redundancy of the device in actual road protection scenarios.

[0048] In this embodiment, energy absorption design calculations were conducted for a 120km / h high-speed collision scenario involving a 120K-level crash buffer vehicle. These calculations covered two typical rear-end collision vehicle masses (1100kg and 2270kg) and two mainstream crash buffer vehicle counterweight specifications (12t and 14t). They also incorporated actual conditions with three different road surface adhesion coefficients: 0.6 in sunny weather, 0.4 in rainy weather, and 0.28 in snowy weather. Ultimately, precise quantitative calculations were completed for the theoretical maximum energy absorption of the crash buffer under the assumption of a completely inelastic collision, and the theoretical minimum energy absorption under the constraints of the maximum allowable slip distance and maximum allowable occupant deceleration. Compliance verification was also performed under all scenario conditions. Table 5 shows the theoretical maximum energy absorption data of the crash buffer under the assumption of a completely inelastic collision, and Table 6 shows the theoretical minimum energy absorption data under the constraints of the maximum allowable slip distance and maximum allowable occupant deceleration.

[0049]

[0050]

[0051] As shown in Table 5, for rear-impact vehicles weighing 1100kg and 2270kg, and for 12t and 14t crash buffer vehicles, under different weather conditions (sunny, rainy, and snowy), the maximum theoretical maximum energy absorption of the crash buffer pads under the assumption of a completely inelastic collision is 1085.16kJ. Furthermore, the sliding distances in all weather conditions (sunny, rainy, and snowy) are less than the standard requirement of 10m safety distance, and the maximum occupant deceleration is less than the standard 20.49g, meeting the design standard requirements. As shown in Table 6, for rear-impact vehicles weighing 1100kg and 2270kg, and for 12t and 14t crash buffer vehicles, under different weather conditions (sunny, rainy, and snowy), the maximum theoretical minimum energy absorption under the constraints of the maximum allowable sliding distance and the maximum allowable occupant deceleration is 914.26kJ. Therefore, in the embodiments of this application, the target design energy absorption of 1085.16kJ is achieved when 1100kg and 2270kg rear-impact vehicles collide with 12t and 14t anti-collision buffer vehicles under different environments such as sunny, rainy, and snowy weather, and under high-speed conditions of 120km / h.

[0052] It should be noted that the theoretical maximum energy absorption of the crash buffer pad under the assumption of a completely inelastic collision in this application is the result of a calculation under the extreme working condition of a completely inelastic collision, assuming no tire-road friction energy loss during the collision and that all collision energy is absorbed by the crash buffer pad. Therefore, the theoretical maximum energy absorption of the crash buffer pad under the assumption of a completely inelastic collision is only related to the mass of the rear-impacting vehicle, the mass of the crash buffer vehicle, and the collision speed, and is independent of the road adhesion coefficient, and does not change with road conditions.

[0053] Preferably, when the allowable frictional dissipation energy is greater than or equal to the total kinetic energy of the system before the collision, the anti-collision buffer pad no longer needs to provide additional minimum energy absorption from the perspective of satisfying the sliding distance and occupant deceleration constraints. The theoretical minimum energy absorption under the corresponding working condition that satisfies the allowable maximum sliding distance and allowable maximum occupant deceleration constraints is taken as 0.

[0054] A 1100kg rear-end collision vehicle, under clear weather conditions ( For example, under this condition, the total kinetic energy of the system before the collision is low, and the allowable frictional dissipation energy is sufficient to cover the energy dissipation requirements of the entire collision process, given the high adhesion coefficient of the road surface. Since energy absorption, as a structural design parameter, cannot be negative, the theoretical minimum energy absorption under this condition, satisfying the constraints of the maximum allowable slip distance and the maximum allowable occupant deceleration, is taken as a non-negative value, i.e. .

[0055] S3. Design an energy absorption module, which consists of multiple layers of honeycomb block-shaped energy absorption units. The effective energy absorption of each layer of honeycomb block-shaped energy absorption units is shown below: , In the formula, This is the layer index for the honeycomb block energy-absorbing unit. For the first The effective energy absorption of layered honeycomb block-shaped energy-absorbing units For the first The effective energy absorption efficiency coefficient of the layered honeycomb block energy absorption unit. For the first The average plateau stress of the layered honeycomb block energy-absorbing unit, For the first The effective cross-sectional area of ​​the layered honeycomb block energy-absorbing unit, which is perpendicular to the main impact direction of the rear-impacting vehicle and actually participates in load transfer, is subjected to pressure. For the first Effective crushing stroke of layered honeycomb block energy-absorbing units.

[0056] In this application, the multi-layer honeycomb block energy-absorbing units are arranged starting from the rearward impact surface of the vehicle and distributed along the main impact direction of the rearward impact vehicle. The effective energy absorption of the next layer of honeycomb block energy-absorbing units is greater than that of the previous layer of honeycomb block energy-absorbing units, thus forming a gradient energy-absorbing structure that is relatively soft in the front, stable in the middle, and enhanced in the rear along the main impact direction of the rearward impact vehicle.

[0057] In this embodiment of the application, "main impact direction" refers to the main direction of transmission of the collision impact load when a rear-facing vehicle impacts the anti-collision buffer pad.

[0058] like Figure 4 As shown, each layer of honeycomb block energy-absorbing unit is an integral block honeycomb aluminum structure, including multiple honeycomb cells with a regular hexagonal cross-section; multiple honeycomb cells are periodically arranged in a plane perpendicular to the honeycomb hole axis, adjacent honeycomb cells share a cell wall and extend through the direction of the honeycomb hole axis; the extension direction of the honeycomb hole of each layer of honeycomb block energy-absorbing unit is in the same direction as the impact load.

[0059] In this application, the width, thickness, yield stress of the honeycomb substrate, characteristic strain rate parameter, strain rate sensitivity index, and substrate density of each layer of honeycomb block energy-absorbing unit are all the same; the cell wall thickness-to-length ratio of the subsequent layer of honeycomb block energy-absorbing unit is greater than that of the previous layer of honeycomb block energy-absorbing unit, that is, the cell wall thickness-to-length ratio of each layer of honeycomb block energy-absorbing unit increases stepwise along the crushing direction, wherein the cell wall thickness-to-length ratio is the ratio of the nominal thickness of the honeycomb cell wall to the side length of the honeycomb cell of that layer of honeycomb block energy-absorbing unit.

[0060] It should be noted that traditional uniform honeycomb structures exhibit significant uneven stress distribution during crushing, specifically: stress concentration and severe deformation near the impact point, and lower stress and insufficient deformation at the far impact point. This unevenness prevents the energy absorption efficiency of the honeycomb material from being fully utilized, and premature compaction is prone to occur near the impact point, severely affecting the overall protective performance. To address this issue, this application adopts a gradient energy absorption structure design, which involves progressively increasing the ratio of cell wall thickness to cell side length of each layer of honeycomb block energy-absorbing units along the crushing direction. Specifically, a lower density honeycomb is used near the impact point, and a higher density honeycomb is used at the far impact point, so that the average platform bearing capacity of each layer of honeycomb block energy-absorbing units gradually increases along the crushing direction. Based on this gradient configuration, the honeycomb near the impact point crushes preferentially in the initial stage of the collision, followed by the middle and far impact point honeycombs participating in energy absorption layer by layer, forming a progressive crushing mode from front to back and from weak to strong. This crushing sequence can effectively avoid premature local compaction and balance the deformation of each layer of material, thereby extending the effective energy absorption time while reducing the abrupt change in collision force and improving the overall energy absorption efficiency and crushing stability of the energy absorption module.

[0061] To prevent the energy-absorbing module from becoming too large along the main impact direction of a rear-facing impact vehicle, which could lead to overall lateral bending, skewed crushing, or in-plane bending instability of the cell wall, the energy-absorbing module in this application also includes multiple partitions. Each partition is respectively disposed between two adjacent layers of honeycomb block energy-absorbing units, at the beginning of the first layer of honeycomb block energy-absorbing units, and at the end of the last layer of honeycomb block energy-absorbing units, to form multiple compartments for accommodating each layer of honeycomb block energy-absorbing units. This restricts the lateral displacement of each layer of honeycomb block energy-absorbing units during the crushing process and ensures that the impact load is uniformly transmitted between adjacent honeycomb block energy-absorbing units.

[0062] Preferably, the effective energy absorption efficiency coefficient of each layer of honeycomb block energy absorption unit is obtained through experimental calibration or simulation calibration, and is an empirically determined coefficient; the effective energy absorption efficiency coefficient of the next layer of honeycomb block energy absorption unit is greater than that of the previous layer of honeycomb block energy absorption unit, that is, the effective energy absorption efficiency coefficient of each layer of honeycomb block energy absorption unit increases in a stepwise manner along the crushing direction.

[0063] It should be noted that the effective energy absorption efficiency coefficient in this application is used to characterize the energy absorption reduction caused by factors such as end constraints, interface friction, local off-center loading, processing errors, installation gaps, and incomplete crushing. Since the honeycomb near the impact end participates in crushing first in the initial stage of the collision, its end constraints and local off-center loading effects are more significant, and the degree of energy absorption reduction is relatively high. Therefore, the effective energy absorption efficiency coefficient of the near impact end is low. Along the impact direction, the honeycomb crushing sequence proceeds sequentially, and the influence of end constraints and local off-center loading on the subsequent honeycomb layers gradually weakens. Therefore, the effective energy absorption efficiency coefficient increases layer by layer.

[0064] Preferably, the average plateau stress of each layer of honeycomb block energy-absorbing unit is obtained through material testing, honeycomb component compression testing, finite element simulation, or theoretical calculation; considering the strain rate strengthening effect of the honeycomb substrate during dynamic impact, the average plateau stress of each layer of honeycomb block energy-absorbing unit is as follows: , In the formula, For the first Yield stress of the honeycomb substrate of the layered honeycomb block energy-absorbing unit; For the first The nominal thickness of the cell wall of the layered honeycomb block energy-absorbing unit, in mm; For the first The side length of the cell in the layered honeycomb block energy-absorbing unit, in mm; For the first The equivalent compression velocity of the layered honeycomb block energy-absorbing unit during major crushing, in mm / s; This is a characteristic strain rate parameter for honeycomb substrates, used to characterize the strain rate scale corresponding to significant dynamic strengthening of the material, in units of... ; is the strain rate sensitivity index for honeycomb substrates, used to characterize the nonlinearity of the increase in platform stress with increasing equivalent compressive strain rate, and is a dimensionless parameter.

[0065] According to the formula for calculating the average plateau stress of each layer of honeycomb block energy-absorbing unit, the average plateau stress of that layer of honeycomb block energy-absorbing unit can be adjusted by adjusting the ratio of the nominal thickness of the honeycomb cell wall to the side length of the honeycomb cell.

[0066] In the embodiments of this application, the cell geometric parameters of the single-layer honeycomb block energy-absorbing unit, namely the nominal thickness of the honeycomb cell wall and the side length of the honeycomb cell, are as follows: Figure 5 As shown.

[0067] It should be noted that, and These factors collectively determine the plateau stress amplification effect of the honeycomb substrate under dynamic crushing conditions. In the embodiments of this application, and Obtained through dynamic compression test of honeycomb substrate, drop weight impact test or material database calibration.

[0068] In this embodiment, the average plateau stress of the subsequent layer of honeycomb block energy-absorbing units is greater than the average plateau stress of the preceding layer of honeycomb block energy-absorbing units.

[0069] In this application, the effective cross-sectional area of ​​each layer of honeycomb block energy-absorbing unit that is perpendicular to the main impact direction of a rear-impacting vehicle and actually participates in load transfer is calculated as follows: , In the formula, For the first The width of the layered honeycomb block energy-absorbing unit, For the first The thickness of the layered honeycomb block energy-absorbing unit.

[0070] It should be noted that the effective cross-sectional area under pressure is the macroscopic projected area of ​​the honeycomb block energy-absorbing unit perpendicular to the main impact direction of the rear-impacting vehicle and actually participating in load transfer and crushing energy absorption. It can be determined based on the outer contour dimensions of the honeycomb module, its installation boundaries, load coverage, and contact state with adjacent pressure-bearing components. In this embodiment, the effective cross-sectional area under pressure of each layer of honeycomb block energy-absorbing units is calculated based on the width and thickness of the honeycomb block energy-absorbing units, such as... Figure 6 As shown.

[0071] In this application, the effective crushing stroke of each layer of honeycomb block energy-absorbing unit is calculated using the following formula: , , In the formula, For the first The length of the layered honeycomb block energy-absorbing unit, For the first Densification strain of layered honeycomb block energy-absorbing units; For the first The equivalent density of layered honeycomb block energy-absorbing units, in kg / m³. 3 ; The density of the substrate for the honeycomb block energy-absorbing unit is expressed in kg / m³. 3 ; For the first The relative density of layered honeycomb block-shaped energy-absorbing units, .

[0072] In this embodiment of the application, the length, width, and thickness of the single-layer honeycomb block-shaped energy-absorbing unit are as follows: Figure 4 As shown; a schematic diagram of the effective crushing stroke of a single-layer honeycomb block energy-absorbing unit is shown below. Figure 7 As shown, where, Figure 7 Figure a shows a top view of a single-layer honeycomb block energy-absorbing unit before it collapses. Figure 7 Figure b is a top view of a single-layer honeycomb block energy-absorbing unit after it has been crushed.

[0073] It should be noted that the densification strain is the critical strain at which a honeycomb material transitions from the stable crushing stage to the densification stage. In the stable crushing stage, the honeycomb cells undergo layer-by-layer buckling and folding, and the stress remains in a relatively stable plateau region, achieving continuous and stable energy dissipation. When the compressive strain exceeds the densification strain, the cell walls are completely folded and compacted, the apparent density of the honeycomb structure increases sharply, the stress rises rapidly, and the energy absorption efficiency decreases significantly.

[0074] In the design of crash cushioning, the compaction strain constitutes the physical upper limit of the effective crushing stroke—exceeding this strain, the compression stroke can no longer provide a stable energy absorption platform, and instead, the sudden increase in stress will cause a sharp increase in occupant deceleration. Therefore, this application limits the effective crushing stroke of each layer of honeycomb block energy absorption unit to within the compression amount corresponding to the compaction strain, ensuring that each layer of honeycomb block energy absorption unit operates within a stable crushing range, thereby achieving sufficient energy absorption while controlling the actual maximum occupant deceleration within an allowable range.

[0075] S4. Based on the effective energy absorption of each layer of honeycomb block energy absorption unit, calculate the total energy absorption of the energy absorption module, as shown below: , In the formula, n is the total number of layers in the honeycomb block energy-absorbing unit. This represents the total energy absorbed by the energy absorption module.

[0076] S5. Based on the target design energy absorption under multiple core collision conditions, check the total energy absorption of the energy absorption module. If the total energy absorption of the energy absorption module is greater than the target design energy absorption under multiple core collision conditions, and the maximum allowable occupant deceleration and crush stability meet the preset requirements, output the design parameters of the energy absorption module; otherwise, return to step S3 to redesign the energy absorption module.

[0077] In this application, the design parameters of the energy absorption module include the total number of layers of honeycomb block energy absorption units, the nominal thickness of the honeycomb cell wall, the side length, thickness, width, length, effective energy absorption efficiency coefficient, effective crushing stroke, yield stress of the honeycomb substrate, equivalent compression rate, characteristic strain rate parameter, strain rate sensitivity index, equivalent density, and substrate density of each layer of honeycomb block energy absorption unit.

[0078] In this application, the standard that allows the maximum occupant deceleration and crush stability to meet the preset requirements is as follows: the maximum occupant deceleration is less than the preset safety threshold; at the same time, in the compression stability simulation, the overall compression process of the energy absorption module is stable, exhibits gradual and uniform crushing, and no obvious instability phenomenon occurs.

[0079] In this embodiment of the application, the preset safety threshold is 20.49g.

[0080] It should be noted that the "maximum permissible occupant deceleration" in step S5 refers to the maximum permissible occupant deceleration pre-set in the design boundary condition definition stage of S1, that is, the design index used as design input, rather than the actual maximum permissible occupant deceleration obtained after simulation calculation.

[0081] like Figure 8-9 As shown, a second aspect of the present invention provides a collision buffer pad, obtained using the aforementioned collision buffer pad design method. The collision buffer pad includes an energy-absorbing module and a skin covering the energy-absorbing module, wherein: The energy absorption module consists of a first buffer zone 1 and a second buffer zone 2 arranged sequentially along the main impact direction of the rearward impact vehicle, and the first buffer zone 1 and the second buffer zone 2 are connected by a first flipping connection mechanism. Both the first buffer zone 1 and the second buffer zone 2 are arranged with the rearward impact surface of the vehicle as the starting point, and multiple layers of honeycomb block-shaped energy-absorbing units are distributed along the main impact direction of the rearward impact vehicle. Within the same buffer zone, the effective energy absorption of the next layer of honeycomb block energy-absorbing units is greater than that of the previous layer of honeycomb block energy-absorbing units; at the same time, the effective energy absorption of the first layer of honeycomb block energy-absorbing units in the second buffer zone 2 is greater than that of the last layer of honeycomb block energy-absorbing units in the first buffer zone 1.

[0082] Preferably, the cell wall thickness-to-length ratio of the first layer of cellular block energy-absorbing units in the second buffer zone 2 is greater than the cell wall thickness-to-length ratio of the last layer of cellular block energy-absorbing units in the first buffer zone 1.

[0083] Preferably, the width and thickness of all honeycomb block energy-absorbing units in each buffer zone are equal; the length of each layer of honeycomb block energy-absorbing units in the same buffer zone is equal, while the length of honeycomb block energy-absorbing units in different buffer zones is unequal.

[0084] In this embodiment of the application, partitions are provided between adjacent layers of honeycomb block energy-absorbing units in each buffer zone, at the beginning of the first layer of honeycomb block energy-absorbing units, and at the end of the last layer of honeycomb block energy-absorbing units.

[0085] Preferably, the first buffer zone 1 and the second buffer zone 2 are connected by a first flipping connection mechanism. The first flipping connection mechanism is used to support the first buffer zone 1 to flip between the 0° working state and the 90° passage state relative to the second buffer zone 2. When the first buffer zone 1 switches from the 0° working state to the 90° passage state, the first buffer zone 1 flips upward around the first flipping connection mechanism.

[0086] like Figure 8As shown, the anti-collision buffer pad also includes a guide part 3 disposed on the impact end face of the first buffer zone 1. The guide part 3 is a trapezoidal block with a narrow front end and a wide rear end. Its wide end is fixed to the impact end face of the first buffer zone 1, and its narrow end faces the direction of the rearward impact vehicle, so as to provide impact position guidance for the rearward impact vehicle.

[0087] In this embodiment, the guide part 3 is a honeycomb block-shaped energy-absorbing unit. Because it has a trapezoidal block structure that is narrow at the front and wide at the rear, its cross-sectional shape along the main impact direction is not a uniform rectangle or column. Unlike the honeycomb block-shaped energy-absorbing units with regular rectangles located inside the buffer zone, it is difficult to calculate its effective energy absorption using uniform design parameters (e.g., nominal thickness of the honeycomb cell wall, side length of the honeycomb cell, thickness, length, width, and effective crushing stroke). Therefore, in this application, the guide part 3 is set as an independent component outside the energy-absorbing module. Although it will also undergo a certain degree of crushing deformation and absorb some impact energy during the collision, it does not participate in the total energy absorption calculation of the energy-absorbing module; that is, its energy absorption contribution is not included.

[0088] In this embodiment, the first buffer zone 1 and the second buffer zone 2 are each independently covered by a skin, while the guide part 3 and the first buffer zone 1 are integrally covered by a skin.

[0089] In this embodiment, the partition and the skin are fixedly connected by riveting.

[0090] Preferably, the anti-collision buffer pad is provided with a first guide reflective strip 5 on both sides, the guide part 3 is provided with a second guide reflective strip 7 on the narrow end face, and warning lights 4 are provided on the left and right sides of the narrow end face of the guide part 3. The warning lights 4 are used to issue a warning signal to vehicles approaching from behind before a collision occurs. The first guide reflective strip 5 and the second guide reflective strip 7 are used to guide the front end of the rearward impact vehicle in the initial stage of the collision.

[0091] In this embodiment, the warning light 4 is communicatively connected to a wireless controller located in the driver's cab, and turns on or off in response to control signals sent by the wireless controller.

[0092] like Figure 10-13 As shown, the third aspect of the present invention provides a crash buffer vehicle, wherein the crash buffer pad is connected to the bottom of the vehicle body through a second flip-connecting mechanism.

[0093] In this application, the second buffer zone 2 of the anti-collision buffer pad is connected to the bottom of the vehicle body through the second flip connection mechanism. The second flip connection mechanism is used to support the second buffer zone 2 to flip between the 0° working state and the 90° passing state relative to the vehicle body. When the second buffer zone 2 switches from the 0° working state to the 90° passing state, the second buffer zone 2 flips upward around the second flip connection mechanism.

[0094] It should be noted that the first and second flipping connection mechanisms used in this application are conventional pin-hinged and hydraulically driven structures in the art. As long as the structural strength is checked and the load-bearing requirements are met, the specific structural details will not be described in detail in this application.

[0095] Preferably, in the 0° operating state, the first buffer zone 1 and the second buffer zone 2 are arranged collinearly in the horizontal direction, and the longitudinal axis of the anti-collision buffer pad is parallel to the road surface.

[0096] Preferably, in the 0° operating state, the ground clearance between the bottom surface of the anti-collision buffer pad and the road surface is 200mm.

[0097] Preferably, the rear of the crash buffer vehicle is detachably provided with a support bracket 6 in the shape of a "bench". When both the first buffer zone 1 and the second buffer zone 2 are flipped to the 90° passage state, the first buffer zone 1 is flipped upward 90° around the first flipping connecting mechanism and stacked on top of the second buffer zone 2 and the vehicle body and in contact with the support bracket 6. The support bracket 6 provides vertical support for the first buffer zone 1.

[0098] Preferably, the sum of the lengths of all the honeycomb block energy-absorbing units in the first buffer zone 1 is less than the length of the crash buffer vehicle's cargo compartment; and the width of each honeycomb block energy-absorbing unit is less than the width of the crash buffer vehicle's cargo compartment.

[0099] In this embodiment of the application, the sum of the lengths of all the honeycomb block energy-absorbing units in the first buffer zone is <4.80m, and the thickness of each honeycomb block energy-absorbing unit is 0.30~0.50m.

[0100] In this embodiment, the anti-collision buffer pad adopts a split, retractable structure design. In the 0° operating state, the anti-collision buffer pad unfolds and lowers behind the vehicle's rear, forming an effective rearward anti-collision energy absorption area to buffer the impact of rear-end collisions. In the 90° passage state, the anti-collision buffer pad flips upwards 90° via a flipping connection mechanism and is stored above the vehicle's rear, reducing the overall rear overhang length and space occupation, facilitating normal vehicle relocation. Specifically, in the 90° passage state, with the anti-collision buffer pad folded and stored above the vehicle's rear, the overall vehicle height (measured from the road surface) is less than 4.00m, and the overall vehicle width is less than 2.55m, meeting the limits of GB 1589-2016 "Limits of External Dimensions, Axle Loads and Mass of Motor Vehicles, Trailers and Vehicle Combinations," and also complying with current Chinese road transport management requirements regarding a total vehicle and cargo height not exceeding 4.00m for oversized transport, ensuring good traffic adaptability and regulatory compliance during non-operational relocation.

[0101] In this application, a three-dimensional finite element model was established based on the designed crash buffer pad to verify the effectiveness of the crash buffer pad designed by this method. In this experiment, the solid model of the crash buffer pad was created by three-dimensional modeling software and then imported into finite element preprocessing software for geometric cleanup, connection definition, and mesh generation; a pickup truck finite element model provided by a publicly available collision safety research institution was used as the rear-impact vehicle model, such as... Figure 14 As shown. The rear-impact vehicle model has a mass of 2270 kg, 721 parts, 979598 nodes, 53294 solid elements, 907067 shell elements, 3113 beam elements, and a total of 963474 elements; the vehicle's pitch inertia is 6059 kg·m. 2 The lateral inertia is 6537 kg·m. 2 The moment of inertia is 1049 kg·m. 2 The z-axis coordinate of the center of gravity is 730.3 mm.

[0102] In this experiment, the main thin-walled components of the crash buffer pad were simulated using Belytschko-Tsay (BT) shell elements with Shell163 elements. The honeycomb block energy-absorbing elements, serving as the primary deformation and energy-absorbing parts, employed a hybrid mesh with quadrilaterals as the main component and triangles as secondary components. In this experiment, the honeycomb block energy-absorbing elements used approximately 19mm × 19mm shell elements, while the mesh size of other components with smaller deformations was controlled within 100mm. The possible contact area between the rear-impact vehicle and the crash buffer pad was set as surface-to-surface contact, and both the rear-impact vehicle and the crash buffer pad were set to single-sided self-contact to prevent local penetration, element inversion, and negative volume phenomena. Furthermore, since most of the thin-walled metal components of the crash buffer pad undergo bending, crushing, and plastic deformation during the collision, a piecewise linear plastic material model was used to define their mechanical response. For rigid supports, equivalent mass blocks, or locally connected structures with relatively small deformation effects in the calculation, rigid body material models or equivalent rigid bodies were used. The material properties of the core components are shown in Table 7. The equivalent plateau stress, yield strength, and plasticity curves of the honeycomb aluminum are imported from material compression tests or supplier data.

[0103]

[0104] In this experiment, for conditions 50 to 53 in MASH-2016 provided in Table 4, condition 51, which involves a frontal collision and the largest rearward-impacting vehicle mass, was selected as the main collision simulation verification condition. A conservative calculation was performed using a 14t equivalent anti-collision buffer vehicle mass. The anti-collision buffer vehicle was simplified to a 14t cuboid or equivalent mass block. Road surface z-direction constraints were applied to the rearward-impacting vehicle and the anti-collision buffer vehicle. The initial speed of the rearward-impacting vehicle was set to 120km / h, the height of the anti-collision buffer pad from the ground was set to 200mm, and the collision calculation time was 0.15s. In the initial state of the collision, the rearward-impacting vehicle and the anti-collision buffer pad were located on the same longitudinal centerline.

[0105] In the compression stability simulation, the anti-collision buffer pad was stable in the overall compression process under the set boundary conditions, without extreme deformation or overall instability. It showed a gradual and uniform crushing without obvious instability.

[0106] In whole-vehicle collision simulation, the B-pillar acceleration of a rear-impacting vehicle is extracted as an occupant safety evaluation indicator. For example... Figure 15 As shown, under the 120km / h condition, the B-pillar acceleration in the low-strength zone is approximately 10g, while the peak B-pillar acceleration in the high-strength zone is approximately 20.1g (after conversion, the occupant deceleration is less than the maximum permissible occupant deceleration of 20.49g), and the B-pillar acceleration is below 20g for most of the collision events. Therefore, it can be determined that the crash buffer still meets the occupant deceleration control requirements under the most unfavorable condition 51, and can thus be used for design verification covering the remaining conditions 50, 52, and 53.

[0107] The dynamic response shows that at 120km / h, the first buffer zone completes the main crushing at about 0.1s and the second buffer zone begins to absorb energy. By 0.15s, the second buffer zone has a large-scale crushing. The vehicle does not show obvious pitch instability and the acceleration response is relatively stable, indicating that the gradient energy absorption structure provided in this application can achieve relatively uniform energy dissipation under high-speed impact.

[0108] In addition, such as Figure 16As shown, in this collision simulation experiment of the crash buffer vehicle, the total energy of the system remained stable at approximately 1260 kJ, and the overall energy change trend during the collision conformed to the law of conservation of energy. In the initial stage of the collision, the system energy mainly existed in the form of vehicle kinetic energy; as the collision progressed, the vehicle kinetic energy gradually decreased and was continuously converted into internal energy through vehicle structural deformation, plastic deformation of the crash buffer honeycomb units, and contact collisions. When the collision lasted for 0.15 seconds, the entire collision process was basically completed, with most of the initial kinetic energy converted into internal energy, and only a small portion dissipated in the form of hourglass energy. In summary, the total energy of the system remained constant during the collision, the conversion process from kinetic energy to internal energy conformed to the energy transfer and dissipation laws in actual collisions, and the proportion of hourglass energy was extremely low, effectively verifying the rationality, numerical stability, and reliability of the calculation results of the crash buffer vehicle collision simulation model established in this application.

[0109] In summary, this invention provides a design method for a crash buffer pad, a crash buffer pad itself, and a crash buffer vehicle. The method uses regulatory crash test conditions as design input, and through quantitative calculations of the theoretical maximum and minimum energy absorption, determines a clearly defined target design energy absorption. Based on this, it employs multi-layered honeycomb block-shaped energy-absorbing units with the axial direction of the honeycomb cells aligned with the main impact direction. The cell wall thickness-to-length ratio of the honeycomb block-shaped energy-absorbing units is progressively increased along the impact direction, forming a gradient energy-absorbing structure from front to back and from weak to strong. This ensures that each layer of energy-absorbing units collapses sequentially, achieving smooth control of occupant deceleration and maximizing energy absorption efficiency throughout the entire collision process. Simultaneously, it incorporates deceleration constraints, slip distance limitations, and energy absorption requirement calculations into a unified design framework, and through a closed-loop process of "design-verification-output," makes the design process repeatable, verifiable, and traceable. This invention has achieved substantial breakthroughs in the precise calibration of energy absorption requirements for anti-collision buffer pads, honeycomb gradient structure design, and parametric engineering implementation. It can be widely applied to maintenance operations, accident handling, and temporary work area protection for highways, urban expressways, and ordinary trunk roads, and has good engineering application prospects and promotion value.

[0110] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A design method for an anti-collision buffer pad, characterized in that, Includes the following steps: S1. Determine the various core collision conditions and the corresponding design parameters for each core collision condition; S2. Based on the design parameters corresponding to each core collision condition, calculate the theoretical maximum energy absorption of the anti-collision buffer pad under the assumption of a completely inelastic collision, and the theoretical minimum energy absorption under the constraints of the maximum allowable slip distance and the maximum allowable occupant deceleration, thereby determining the target design energy absorption under various core collision conditions. Specifically, step S2 is as follows: S21. If the rear-impacting vehicle is the main kinetic energy input, the total kinetic energy of the system before the collision in each core collision scenario is as follows: ， In the formula, j is the index of the number of core collision conditions. Let be the total kinetic energy of the system before the collision in the j-th core collision scenario. Let be the mass of the vehicle in a rear-end collision under the j-th core collision scenario. Let be the rearward collision speed of the vehicle in the j-th core collision scenario. S22. Calculate the theoretical maximum energy absorption of the anti-collision buffer pad under the assumption of a completely inelastic collision under each core collision condition. Specifically: S221. Based on the law of conservation of momentum, calculate the common velocity of the front and rear vehicles after a perfectly inelastic collision under each core collision condition, as shown below: ， In the formula, Let be the common velocity of the front and rear vehicles after a completely inelastic collision under the j-th core collision condition. The mass of the crash buffer vehicle for the j-th core collision condition; S222. Based on the common velocity of the front and rear vehicles after a fully inelastic collision under each core collision condition, calculate the post-collision system kinetic energy under the fully inelastic collision condition for each core collision condition, as shown below: ， In the formula, Let be the post-collision system kinetic energy under the completely inelastic collision condition of the j-th core collision condition; S223. Based on the total kinetic energy of the system before collision under each core collision condition and the kinetic energy of the system after collision under the completely inelastic collision condition, calculate the theoretical maximum energy absorption of the anti-collision buffer pad under the assumption of a completely inelastic collision under each core collision condition, as shown below: ， In the formula, The theoretical maximum energy absorption of the anti-collision buffer pad under the assumption of a completely inelastic collision under the j-th core collision condition; S23. Calculate the theoretical minimum energy absorption under the constraints of the maximum allowable slip distance and the maximum allowable occupant deceleration for each core collision condition. Specifically: S231. Based on the maximum permissible occupant deceleration for each core collision scenario, calculate the limit deceleration distance for a rear-impact vehicle to decelerate from the collision speed to zero under each core collision scenario, as shown below: ， In the formula, Let be the limit deceleration distance for a rear-impact vehicle to decelerate from its collision velocity to zero under the j-th core collision condition. Let be the maximum permissible occupant deceleration for the j-th core collision scenario; S232. Based on the maximum permissible slip distance, road surface adhesion coefficient, and the ultimate deceleration distance corresponding to the rear-impact vehicle's deceleration from the collision speed to zero for each core collision condition, calculate the energy dissipated by the crash buffer vehicle through tire-road friction within the maximum permissible slip distance, and the energy dissipated by the rear-impact vehicle through tire-road friction within the ultimate deceleration distance. The sum of these two values ​​is taken as the permissible frictional dissipation energy for each core collision condition, as shown below: ， In the formula, Let the allowable frictional dissipation energy be for the j-th core collision condition. Let be the road surface adhesion coefficient for the j-th core collision condition. The gravitational acceleration of a vehicle in a rear-end collision. Let be the maximum permissible slip distance for the j-th core collision condition; S233. Based on the total kinetic energy of the system before the collision and the allowable frictional dissipation energy under each core collision condition, calculate the theoretical minimum energy absorption under the constraints of the maximum allowable slip distance and the maximum allowable occupant deceleration, as shown below: ， In the formula, The theoretical minimum energy absorption under the constraints of the maximum allowable slip distance and the maximum allowable occupant deceleration under the j-th core collision condition; S24. Based on the theoretical maximum energy absorption of the anti-collision buffer pad under the assumption of a completely inelastic collision under various core collision conditions, and the theoretical minimum energy absorption under the constraints of the maximum allowable slip distance and the maximum allowable occupant deceleration, the target design energy absorption under various core collision conditions is determined as follows: ， In the formula, Energy absorption is designed for the target under various core collision conditions, where J is the total number of core collision conditions. S3. Design an energy absorption module, which consists of multiple layers of honeycomb block-shaped energy absorption units. The effective energy absorption of each layer of honeycomb block-shaped energy absorption units is shown below: ， In the formula, This is the layer index for the honeycomb block energy-absorbing unit. For the first The effective energy absorption of layered honeycomb block-shaped energy-absorbing units For the first The effective energy absorption efficiency coefficient of the layered honeycomb block energy absorption unit. For the first The average plateau stress of the layered honeycomb block energy-absorbing unit, For the first The effective cross-sectional area of ​​the layered honeycomb block energy-absorbing unit, which is perpendicular to the main impact direction of the rear-impacting vehicle and actually participates in load transfer, is subjected to pressure. For the first Effective crushing stroke of layered honeycomb block energy-absorbing units; S4. Based on the effective energy absorption of each layer of honeycomb block energy absorption unit, calculate the total energy absorption of the energy absorption module, as shown below: ， In the formula, n is the total number of layers in the honeycomb block energy-absorbing unit. This represents the total energy absorbed by the energy absorption module. S5. Based on the target design energy absorption under multiple core collision conditions, check the total energy absorption of the energy absorption module. If the total energy absorption of the energy absorption module is greater than the target design energy absorption under multiple core collision conditions, and the maximum allowable occupant deceleration and crush stability meet the preset requirements, output the design parameters of the energy absorption module; otherwise, return to step S3 to redesign the energy absorption module.

2. The design method of an anti-collision buffer pad according to claim 1, characterized in that, Based on the target protection level, applicable road scenarios, and regulatory test conditions, multiple core collision conditions are determined; based on the target protection level, applicable road scenarios, relevant road traffic safety protection regulations, and technical standards, the design parameters corresponding to each core collision condition are determined. The design parameters for each core collision scenario include the mass of the rear-impact vehicle, the collision speed of the rear-impact vehicle, the mass of the crash buffer vehicle, the maximum permissible occupant deceleration, the maximum permissible slip distance, and the road surface adhesion coefficient. The design parameters of the energy absorption module include the total number of layers of honeycomb block energy absorption units, the nominal thickness of the honeycomb cell wall, the side length, thickness, width, length, effective energy absorption efficiency coefficient, effective crushing stroke, yield stress of the honeycomb substrate, equivalent compression rate, characteristic strain rate parameter, strain rate sensitivity index, equivalent density, and substrate density of each layer of honeycomb block energy absorption unit. The standard for both the maximum allowable occupant deceleration and crush stability to meet the preset requirements is as follows: the maximum allowable occupant deceleration is less than the preset safety threshold; at the same time, in the compression stability simulation, the overall compression process of the energy absorption module is stable, exhibits gradual and uniform crushing, and no obvious instability phenomenon is observed. The design method of the anti-collision buffer pad is applicable to all speed conditions from 60km / h to 120km / h.

3. The design method of an anti-collision buffer pad according to claim 1, characterized in that, When the allowable frictional dissipation energy is greater than or equal to the total kinetic energy of the system before the collision, the anti-collision buffer pad no longer needs to provide additional minimum energy absorption from the perspective of satisfying the sliding distance and occupant deceleration constraints. The theoretical minimum energy absorption under the corresponding working condition that satisfies the allowable maximum sliding distance and allowable maximum occupant deceleration constraints is taken as 0.

4. The design method of an anti-collision buffer pad according to claim 1, characterized in that, The multi-layer honeycomb block energy absorption units are arranged starting from the rearward impact surface of the vehicle and distributed along the main impact direction of the rearward impact vehicle. The effective energy absorption of the next layer of honeycomb block energy absorption units is greater than that of the previous layer of honeycomb block energy absorption units, thus forming a gradient energy absorption structure that is softer in the front, stable in the middle and enhanced in the rear along the main impact direction of the rearward impact vehicle. The energy absorption module also includes multiple partitions, each partition being disposed between two adjacent honeycomb block energy absorption units, at the beginning of the first honeycomb block energy absorption unit, and at the end of the last honeycomb block energy absorption unit, to form multiple compartments for accommodating each layer of honeycomb block energy absorption units. Each layer of honeycomb block energy-absorbing unit is an integral block honeycomb aluminum structure, including multiple honeycomb cells with a regular hexagonal cross-section; multiple honeycomb cells are periodically arranged in a plane perpendicular to the honeycomb hole axis, adjacent honeycomb cells share a cell wall and extend through along the honeycomb hole axis; the honeycomb hole extension direction of each layer of honeycomb block energy-absorbing unit is in the same direction as the impact load. The width, thickness, yield stress of the honeycomb substrate, characteristic strain rate parameters, strain rate sensitivity index, and substrate density of each layer of honeycomb block energy-absorbing unit are all the same; the cell wall thickness-to-length ratio of the subsequent layer of honeycomb block energy-absorbing unit is greater than that of the previous layer of honeycomb block energy-absorbing unit, that is, the cell wall thickness-to-length ratio of each layer of honeycomb block energy-absorbing unit increases stepwise along the crushing direction, wherein the cell wall thickness-to-length ratio is the ratio of the nominal thickness of the honeycomb cell wall to the side length of the honeycomb cell of that layer of honeycomb block energy-absorbing unit.

5. The design method of an anti-collision buffer pad according to claim 4, characterized in that, The effective energy absorption efficiency coefficient of each layer of honeycomb block energy absorption unit is obtained through experimental calibration or simulation calibration and is an empirical value coefficient; the effective energy absorption efficiency coefficient of the next layer of honeycomb block energy absorption unit is greater than that of the previous layer of honeycomb block energy absorption unit, that is, the effective energy absorption efficiency coefficient of each layer of honeycomb block energy absorption unit increases in a stepwise manner along the crushing direction. The average plateau stress of each layer of honeycomb block energy-absorbing unit was obtained through material testing, honeycomb component compression testing, finite element simulation, or theoretical calculation. Furthermore, considering the strain rate strengthening effect of the honeycomb substrate during dynamic impact, the average plateau stress of each layer of honeycomb block energy-absorbing unit is as follows: ， In the formula, For the first Yield stress of the honeycomb substrate of the layered honeycomb block energy-absorbing unit; For the first The nominal thickness of the cell wall of the layered honeycomb block energy-absorbing unit, in mm; For the first The side length of the cell in the layered honeycomb block energy-absorbing unit, in mm; For the first The equivalent compression velocity of the layered honeycomb block energy-absorbing unit during major crushing, in mm / s; This is a characteristic strain rate parameter for honeycomb substrates, used to characterize the strain rate scale corresponding to significant dynamic strengthening of the material, with units of 1000 μm. ; is the strain rate sensitivity index of the honeycomb substrate, used to characterize the nonlinearity of the increase in platform stress with increasing equivalent compressive strain rate, and is a dimensionless parameter; The effective cross-sectional area of ​​each layer of honeycomb block energy-absorbing unit, which is perpendicular to the main impact direction of a rear-impacting vehicle and actually participates in load transfer, is calculated as follows: ， In the formula, For the first The width of the layered honeycomb block energy-absorbing unit, For the first The thickness of the layered honeycomb block energy-absorbing unit; The effective crushing stroke of each layer of honeycomb block energy-absorbing unit is calculated using the following formula: ， ， In the formula, For the first The length of the layered honeycomb block energy-absorbing unit, For the first Densification strain of layered honeycomb block energy-absorbing units; For the first The equivalent density of layered honeycomb block energy-absorbing units, in kg / m³. 3 ; The density of the substrate for the honeycomb block energy-absorbing unit is expressed in kg / m³. 3 ; For the first The relative density of layered honeycomb block-shaped energy-absorbing units, .

6. A shock-absorbing pad, characterized in that, The impact buffer pad is obtained by the design method of any one of claims 1-5, wherein the impact buffer pad includes an energy-absorbing module and a skin covering the energy-absorbing module, wherein: The energy absorption module consists of a first buffer zone and a second buffer zone arranged sequentially along the main impact direction of the rearward-impacting vehicle, and the first buffer zone and the second buffer zone are connected by a first flipping connection mechanism. Both the first and second buffer zones are arranged with the rearward impact surface of the vehicle as the starting point, and multiple layers of honeycomb block-shaped energy-absorbing units are distributed along the main impact direction of the rearward-impacting vehicle. Within the same buffer zone, the effective energy absorption of the next layer of honeycomb block energy-absorbing units is greater than that of the previous layer of honeycomb block energy-absorbing units; at the same time, the effective energy absorption of the first layer of honeycomb block energy-absorbing units in the second buffer zone is greater than that of the last layer of honeycomb block energy-absorbing units in the first buffer zone.

7. The anti-collision buffer pad according to claim 6, characterized in that, The cell wall thickness-to-length ratio of the first layer of honeycomb block energy-absorbing units in the second buffer zone is greater than the cell wall thickness-to-length ratio of the last layer of honeycomb block energy-absorbing units in the first buffer zone. All honeycomb block energy-absorbing units in each buffer zone have the same width and thickness; the lengths of honeycomb block energy-absorbing units in each layer within the same buffer zone are equal, while the lengths of honeycomb block energy-absorbing units in different buffer zones are not equal. Each buffer zone has a partition between two adjacent honeycomb block energy-absorbing units, at the beginning of the first honeycomb block energy-absorbing unit, and at the end of the last honeycomb block energy-absorbing unit. The first buffer zone and the second buffer zone are connected by a first flipping connection mechanism. The first flipping connection mechanism is used to support the first buffer zone to flip between the 0° working state and the 90° passage state relative to the second buffer zone. When the first buffer zone switches from the 0° working state to the 90° passage state, the first buffer zone flips upward around the first flipping connection mechanism. The anti-collision buffer pad also includes a guide portion disposed on the impact end face of the first buffer zone. The guide portion is a trapezoidal block that is narrow at the front end and wide at the rear end. Its wide end is fixed to the impact end face of the first buffer zone, and its narrow end faces the direction of the rearward impact vehicle. The first and second buffer zones are each independently covered by a skin, while the guide section and the first buffer zone are integrally covered by a skin.

8. A collision buffer vehicle, characterized in that, The vehicle has a collision buffer pad as described in any one of claims 6-7, wherein the collision buffer pad is connected to the bottom of the vehicle body via a second flip-connecting mechanism.

9. A collision buffer vehicle according to claim 8, characterized in that, The second buffer zone of the anti-collision buffer pad is connected to the bottom of the vehicle body through the second flipping connection mechanism. The second flipping connection mechanism is used to support the second buffer zone to flip between the 0° working state and the 90° passing state relative to the vehicle body. When the second buffer zone switches from the 0° working state to the 90° passing state, the second buffer zone flips upward around the second flipping connection mechanism. In the 0° operating state, the first buffer zone and the second buffer zone are arranged collinearly in the horizontal direction, and the longitudinal axis of the anti-collision buffer pad is parallel to the road surface; at the same time, in the 0° operating state, the ground clearance between the bottom surface of the anti-collision buffer pad and the road surface is 200mm. The rear of the crash buffer vehicle is detachably equipped with a support bracket in the shape of a "bench". When both the first buffer zone and the second buffer zone are flipped to the 90° passage state, the first buffer zone is flipped upward 90° around the first flipping connection mechanism and stacked on top of the second buffer zone and the vehicle body and in contact with the support bracket. The support bracket provides vertical support to the first buffer zone. The sum of the lengths of all the honeycomb block energy-absorbing units in the first buffer zone is less than the length of the crash buffer vehicle's cargo compartment; the width of each honeycomb block energy-absorbing unit is less than the width of the crash buffer vehicle's cargo compartment.

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