One-dimensional granular chain shock absorber with prolonged action time

Abstract

This invention discloses a one-dimensional particle chain buffer that prolongs the impact time, belonging to the field of smart materials design. The invention consists of a composite particle chain composed of three uniform particle chains, all with identical particle material parameters except for yield strength. The delay in impact time can be adjusted by changing the yield strength of the middle particle material; that is, as the yield strength of the middle particle material decreases, the shock wave propagation speed in the particle chain gradually decreases, thereby prolonging the impact time at the output end. This invention provides a novel technical approach for structural protection under low-speed and high-speed impact conditions. By placing this invention between the impact loading end and the impacted structure, the impact resistance of the structure is enhanced by prolonging the impact response time of the impacted structure.

Description

Technical Field

[0001] This invention belongs to the field of smart material design and mainly relates to a one-dimensional particle chain buffer that prolongs the impact time. Background Technology

[0002] Impact phenomena, such as earthquakes, explosions, and car collisions, frequently occur in nature and in engineering applications. These impacts not only damage buildings but also endanger human life and health. Therefore, how to implement impact protection is an important aspect of impact problem research.

[0003] Based on their different mechanisms of action, common impact protection falls into two categories: one is to limit the impact energy to an acceptable range for the impacted object; the other is to reduce the propagation speed of the shock wave and prolong the time it takes for the shock wave to reach the impacted object, giving the impacted object sufficient time to respond to the impact.

[0004] Particulate materials have become a hot topic in impact protection research due to their unique highly nonlinear solitary wave propagation characteristics and excellent designability. By designing the size, density, elastic modulus, and arrangement of particles, the solitary waves in the particle chain can be actively controlled, thereby reducing impact energy and prolonging impact time. Summary of the Invention

[0005] The purpose of this invention is to design a one-dimensional particle chain buffer that prolongs the impact time. By changing the yield strength of the middle section of the particle material, the particle chain slows down the propagation speed of the shock wave after being impacted, thus prolonging the impact time and achieving the purpose of mitigating the impact.

[0006] To achieve the above objectives, the solution of the present invention is:

[0007] A one-dimensional particle chain buffer that prolongs the impact time is provided. The buffer is a three-segment composite particle chain composed of particles with the same spherical diameter. In the three-segment composite particle chain, the yield strength of the middle segment particle material is different from that of the preceding and following segments particle materials, while the yield strength of the preceding and following segments particle materials is the same.

[0008] Furthermore, the particle materials in the three-segment composite particle chain have completely identical material parameters except for the yield strength.

[0009] Furthermore, the other material parameters include sphere diameter, elastic modulus, density, and Poisson's ratio.

[0010] Furthermore, in the three-segment composite particle chain, each segment consists of five or more particles.

[0011] Furthermore, the diameter of the particles in the three-segment composite particle chain is 20 mm.

[0012] Furthermore, the three-segment composite particle chain controls the impact time by adjusting the yield strength of the middle segment particle material to change the propagation speed of the incident shock wave.

[0013] Furthermore, when the yield strength ratio λ of the middle segment particle material to that of the front and rear segment particle materials is less than 1, as λ decreases, the propagation speed of the incident shock wave in the three-segment composite particle chain decreases, and the time for the incident shock wave to reach the output end of the three-segment composite particle chain gradually increases. However, the amplitude ratio η of the contact force between the output end and the input end of the three-segment composite particle chain gradually decreases, and the energy dissipation gradually increases. When λ > 1, as λ increases, the propagation speed of the incident shock wave in the three-segment composite particle chain increases, and both the time for the incident shock wave to reach the output end and the amplitude ratio η gradually decrease.

[0014] Furthermore, the three-segment composite particle chain is placed between the impact loading end and the impacted structure end to delay the impact time of the impacted structure and achieve structural protection.

[0015] Compared with existing technologies, the significant advantages of this invention are: In the one-dimensional three-segment composite particle chain designed in this invention, by altering the yield strength of the middle segment particle material, the particle chain slows down the propagation speed of the shock wave and prolongs the impact time after being subjected to impact, thereby achieving the purpose of mitigating the impact. During the propagation of the shock wave throughout the particle chain, the yield strength of the middle segment particle material decreases. The overall energy loss of the one-dimensional three-segment particle chain does not increase monotonically, but the overall shock wave arrival time at the boundary can be continuously extended, thus prolonging the impact time. This invention has broad application prospects in fields such as earthquake resistance and structural protection. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of a one-dimensional three-segment composite particle chain buffer structure;

[0017] Figure 2 These are the contact force-time curves of the incident and output interfaces under different yield strength ratios: (a) is λ = 3.68, (b) is λ = 1.98, (c) is λ = 1.34, (d) is λ = 1.00, (e) is λ = 0.40, and (f) is λ = 0.23.

[0018] Figure 3 It is the wave velocity throughout the entire particle chain;

[0019] Figure 4 These are the shock wave input and output curves of the composite particle chain;

[0020] Figure 5 It represents the relationship between the amplitude ratio of the output wave to the incident wave and the delay time and the yield strength ratio. Detailed Implementation

[0021] The present invention will be further described in detail below with reference to specific embodiments.

[0022] This invention provides a one-dimensional particle chain buffer that prolongs the impact duration. The buffer is a three-segment composite particle chain composed of particles with uniform spherical diameters. In this three-segment composite particle chain, the yield strength of the middle segment particles differs from that of the preceding and following segments, while the yield strengths of the first and third segments are the same. For the one-dimensional three-segment composite particle chain, the number of particles in the first and third segments must be greater than or equal to 5, and their material properties must be completely identical. The middle segment particles, except for their yield strength, have the same material parameters as the first and second segments.

[0023] In one embodiment, such as Figure 1 As shown, a one-dimensional particle chain buffer that prolongs the impact time is provided. It consists of a three-segment composite elasto-plastic particle chain composed of particles with uniform spherical diameter. Each segment of the particle chain comprises five spherical particles with identical geometric dimensions and material properties, each particle having a diameter of 20 mm. Except for yield strength, all material parameters of the particles in the three-segment composite particle chain are identical, including diameter, elastic modulus, density, and Poisson's ratio. The yield strengths of the particles in the first and third segments are exactly the same, while the particles in the middle segment differ only in their yield strength.

[0024] Define λ as the ratio of the yield strength of the second segment of particle material to the yield strengths of the first and third segments, and define η as the ratio of the contact force amplitudes at the output and input ends of the three-segment composite particle chain. For example... Figures 2 to 5 As shown, when λ = 1, a stable shock wave exists in the homogeneous elastic particle chain, and its energy and wave velocity do not attenuate. When λ < 1, as λ decreases, the propagation velocity of the incident shock wave in the three-segment composite particle chain decreases, the time for the incident shock wave to reach the output end of the three-segment composite particle chain gradually increases, but the amplitude ratio η decreases rapidly, and the energy dissipation gradually decreases. When λ > 1, as λ increases, the propagation velocity of the incident shock wave in the three-segment composite particle chain increases, and both the time for the incident shock wave to reach the output end and the amplitude ratio η gradually decrease.

[0025] In summary, during the propagation of the shock wave along the entire particle chain, the yield strength of the middle segment of the particle material is reduced. The overall energy loss of the one-dimensional three-segment particle chain does not increase monotonically, but the overall shock wave arrival time at the boundary can be continuously extended, thereby prolonging the impact time.

[0026] By placing a three-segment composite particle chain between the impact loading (input) end and the impacted structure (output) end, the propagation speed of the incident shock wave can be changed by adjusting the yield strength of the particle material in the middle segment, thereby controlling the impact duration.

[0027] This invention relates to a one-dimensional particle chain buffer that prolongs the impact time. Placed between the impact loading input and the output of the impacted structure, it effectively extends the impact time of the shock wave entering the impacted structure. The delay in impact time can be adjusted by changing the yield strength of the intermediate particle material; that is, as the yield strength of the intermediate particle material decreases, the propagation speed of the shock wave in the particle chain gradually decreases, thereby prolonging the impact time at the output end.

[0028] This invention provides a novel technical approach for structural protection under low-speed and high-speed impact conditions. By placing the invention between the impact loading end and the impacted structure, and by changing the yield strength of the intermediate granular material, the particle chains slow down the propagation speed of the shock wave after being impacted. This extends the response time of the impacted structure against the impact, thereby mitigating the impact and enhancing the structure's impact resistance.

[0029] The above embodiments are merely illustrative of the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications made to the technical solutions based on the technical concept proposed in this invention shall fall within the scope of protection of this invention.

Claims

1. A one-dimensional particle chain buffer that prolongs the impact duration, characterized in that, The buffer is a three-segment composite particle chain composed of particles with uniform diameter. In the three-segment composite particle chain, the yield strength of the middle segment particle material is different from that of the preceding and following segments particle materials, while the yield strength of the preceding and following segments particle materials is the same. The three-segment composite particle chain controls the impact time by adjusting the yield strength of the middle segment particle material to change the propagation speed of the incident shock wave. When the yield strength ratio λ of the middle segment particle material to that of the front and rear segments particle materials is less than 1, as λ decreases, the propagation speed of the incident shock wave in the three-segment composite particle chain decreases, and the time for the incident shock wave to reach the output end of the three-segment composite particle chain gradually increases. However, the amplitude ratio η of the contact force between the output end and the input end of the three-segment composite particle chain gradually decreases, and the energy dissipation gradually increases. When λ > 1, as λ increases, the propagation speed of the incident shock wave in the three-segment composite particle chain increases, and both the time for the incident shock wave to reach the output end and the amplitude ratio η gradually decrease.

2. The one-dimensional particle chain buffer for prolonging impact time according to claim 1, characterized in that, In the three-segment composite particle chain, the particle materials of each segment of the particle chain have completely identical material properties except for the yield strength.

3. A one-dimensional particle chain buffer for prolonging impact time according to claim 2, characterized in that, Other material properties include sphere diameter, elastic modulus, density, and Poisson's ratio.

4. A one-dimensional particle chain buffer for prolonging impact time according to claim 1, characterized in that, In the three-segment composite particle chain, each segment consists of more than 5 particles.

5. A one-dimensional particle chain buffer for prolonging impact time according to claim 1, characterized in that, The sphere diameter of the particles in the three-segment composite particle chain is 20 mm.

6. A one-dimensional particle chain buffer for prolonging impact time according to claim 1, characterized in that, The three-segment composite particle chain is placed between the impact loading end and the impacted structure end to delay the impact time of the impacted structure and achieve structural protection.

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