Interlaced distributed corrugated fiber shield for intercepting multiple fragments

Abstract

The present application belongs to the technical field of fragment protection, and particularly relates to an interlaced distributed corrugated fiber protection structure for intercepting multiple fragments. The protection structure comprises interlaced upper and lower corrugated fiber plates, the two ends of the upper and lower corrugated fiber plates are in plane contact and are fixed through a fixing structure, the cross section of the upper corrugated fiber plate is trapezoidal, the cross section of the lower corrugated fiber plate is inverted trapezoidal, and the cell structure size of the upper and lower corrugated fiber plates is the same. The interlaced distribution makes each fragment experience the interception of the corrugated web section and the corrugated flange section. In the present application, the in-plane excess material of the corrugated fiber improves the ability of the structure to deform out of the plane, and especially for multiple fragment strikes, the impact hazards can be dispersed to provide sufficient protective material for each impact area. The interlaced structure design can effectively avoid the defect of unstable protection performance caused by the difference in the impact position, and improve the protection stability and reliability of the structure for multiple fragment multi-point distributed impact.

Description

Technical Field

[0001] This invention belongs to the field of fragment protection technology, specifically relating to an interlaced distributed corrugated fiber protective structure for intercepting multiple fragments. Background Technology

[0002] While the mechanisms and structural design of protective structures against single fragments are becoming increasingly sophisticated, real-world scenarios involving high-speed rail, space debris, and explosions often involve multiple fragments or debris impacts. Research indicates that effective protective structures designed for single fragments often experience a significant decrease in their interception rate when subjected to multiple fragment impacts. Therefore, it is necessary to design protective structures that address the synergistic destructive characteristics of multiple fragments. Especially for irregularly shaped targets, designing flexible protective structures based on more flexible materials to intercept multiple fragments is of great significance.

[0003] One known bulletproof device (US2022 / 0107161 A1) uses a continuous V-shaped arrangement to create a corrugated appearance. It primarily utilizes its uneven surface to increase the contact area with fragments and employs techniques to deflect them, achieving efficient protection. However, this design limits its applicability to rigid materials (such as steel, aluminum, and ceramics), resulting in a larger mass and limited flexibility for protection in irregular spaces. Another patent filed earlier by the inventor, "A Corrugated Annular Flexible Composite Explosion-Proof Device (CN 114459306A)," utilizes corrugated fibers to provide lateral restraint for embedded foam, thereby increasing the foam's energy dissipation from impacts and promoting synergistic protection against blast waves and fragments. However, the protection efficiency against multiple fragments still needs improvement. Summary of the Invention

[0004] In view of this, the purpose of this invention is to provide a staggered distributed corrugated fiber protective structure for intercepting multiple fragments. In this invention, the corrugated fibers pre-store excess in-plane material to enhance the structure's ability to deform outwards, particularly effective against multi-fragment impacts, dispersing the impact damage and providing sufficient protective material to each impact zone. The staggered structural design effectively avoids the instability in protective performance that may be caused by differences in impact location, improving the structure's stability and reliability against multi-fragment, multi-point distributed impacts; simultaneously, it provides assembly conditions for modular engineering applications.

[0005] To achieve the above objectives, the technical solution of the present invention is as follows.

[0006] A staggered distributed corrugated fiber protective structure for intercepting multiple fragments includes staggered upper and lower corrugated fiber plates. The two ends of the upper and lower corrugated fiber plates are in planar contact and fixed by a fixing structure. The cross-section of the upper corrugated fiber plate is trapezoidal, and the cross-section of the lower corrugated fiber plate is inverted trapezoidal. The cell structure dimensions of the upper and lower corrugated fiber plates are the same. The staggered distribution ensures that each fragment is intercepted by the corrugated web section and the corrugated flange section.

[0007] Furthermore, the number of cells n × cell span m ≥ the smallest circumcircle diameter d among the multiple fragments. i Cell span m ≥ minimum spacing between two fragments, corrugated web width d = (0.8~1.2) × corrugated flange width b, corrugated height h = (0.6~1.0) × corrugated web width d, single-layer fiber thickness ≤ unidirectional thickness t of corrugated fiberboard < 0.2 × corrugated height h.

[0008] Furthermore, the ratio of fragment spacing to fragment diameter is >10.

[0009] Furthermore, the corrugated web width d = (0.9~1.0) × corrugated flange width b, and the corrugation height h = (0.9~1.0) × corrugated web width d.

[0010] Furthermore, the width of the corrugated web d = the width of the corrugated flange b = the height of the corrugations h.

[0011] Furthermore, the fiber is ultra-high molecular weight polyethylene fiber. More preferably, the molecular weight of the polyethylene fiber is 1.8 million to 3.8 million.

[0012] Furthermore, the fiberboard is obtained by laminating multiple layers of non-woven unidirectional fabric.

[0013] Beneficial effects

[0014] This invention provides an interlaced distributed corrugated fiber protective structure for intercepting multiple fragments. The interlaced distributed corrugated fiber structure fully utilizes the concave and convex shape characteristics of the corrugations, reducing the probability of multiple fragments simultaneously impacting the protective structure and reducing the degree of damage caused by multiple fragments competing for a limited number of fibers. On the one hand, it provides greater out-of-plane deformation capability by increasing the in-plane fiber content, thereby increasing the energy absorption time of the fibers; on the other hand, it increases the complexity of the impact process of the fragments by utilizing the spatial interlaced arrangement, so that each fragment can be intercepted by the corrugated web section and the corrugated flange section, while also improving the uniformity and stability of the interlaced distributed corrugated structure in intercepting multiple fragments.

[0015] This invention provides an interlaced distributed corrugated fiber protective structure for intercepting multiple fragments. The protective advantages of this structure are specifically manifested in the following ways: During fragment interception, the corrugated structure first utilizes its concave-convex shape to reduce the probability of simultaneous impact from multiple fragments. This promotes out-of-plane deformation of the fiber layer first impacted by the fragment, which in turn drives the adjacent fiber layers that have not yet been impacted, allowing them to achieve an out-of-plane expansion velocity in the same direction as the fragment impact. This results in the adjacent fiber layers providing active protection against incoming fragments. The corrugated fiber, with its unique corrugated configuration, enhances the stress propagation distance and propagation coefficient between corrugated units within the layer, effectively reducing or avoiding vicious competition among multiple fragments and ensuring sufficient protective fiber content for each fragment. As the corrugated fibers flow within the plane, the proportion of tensile failure under projectile impact is significantly increased. Compared to traditional flat fiber protection, which is primarily based on shear failure (generally, the energy absorbed by tensile failure per unit volume is much higher than that corresponding to shear failure), this shift in the dominant failure mode further improves the energy absorption efficiency of the corrugated fiber structure. Meanwhile, this design of in-plane fiber allowance reduces the sensitivity of structural protection performance to surrounding constraints. In other words, in practical applications, different levels of constraints have little impact on the protective ability of corrugated fibers (traditional flat fiber is more sensitive to constraints, and its protection efficiency will decrease as the degree of constraint increases). This is beneficial for corrugated fibers to be flexibly adapted to existing constraint devices or structures. Attached Figure Description

[0016] Figure 1 This is a schematic diagram illustrating the interlaced distributed corrugated fiber structure.

[0017] Figure 2 A schematic diagram illustrating the cross-section of an interleaved distributed corrugated fiber structural unit: where d is the width of the corrugated web, b is the width of the corrugated flange, h is the corrugated height, m ​​is the span of the structural unit, and t is the unidirectional thickness of the interleaved distributed corrugated fiber structure.

[0018] Figure 3 This is a schematic diagram illustrating the model for numerical simulation, where 1-fixation device, 2-fragment, and 3-fiber protective structure.

[0019] Figure 4 This is a schematic diagram of the distribution of multiple fragment impacts, where d i denoted as the smallest circumcircle diameter among the multiple fragments, and s is the minimum distance between any two fragments.

[0020] Figure 5 This diagram illustrates the dynamic response of an interlaced distributed corrugated fiber structure and a traditional flat fiber structure when subjected to impact from multiple fragments.

[0021] Figure 6This diagram illustrates the stress distribution when an interlaced distributed corrugated fiber structure and a traditional flat fiber structure are impacted by multiple fragments.

[0022] Figure 7 A schematic diagram of the velocity-time history curves of multiple fragments impacting an interlaced distributed corrugated fiber structure and a traditional flat fiber structure. Detailed Implementation

[0023] The present invention will be further described in detail below with reference to specific embodiments.

[0024] like Figure 1-3 As shown, an interleaved distributed corrugated fiber protective structure 3 for intercepting multiple fragments includes an upper corrugated fiber plate and a lower corrugated fiber plate that are interleaved. The two ends of the upper and lower corrugated fiber plates are in planar contact and are fixed by a fixing structure 1. The cross-section of the upper corrugated fiber plate is trapezoidal, and the cross-section of the lower corrugated fiber plate is inverted trapezoidal. The cell structure dimensions of the upper and lower corrugated fiber plates are the same. The interleaved distribution ensures that each fragment 2 is intercepted by the corrugated web section and the corrugated flange section.

[0025] Furthermore, the number of cells n × cell span m ≥ the smallest circumcircle diameter d among the multiple fragments. i Cell span m ≥ minimum spacing s between two fragments, corrugated web width d = (0.8~1.2) × corrugated flange width b, corrugated height h = (0.6~1.0) × corrugated web width d, single-layer fiber thickness ≤ unidirectional thickness t of corrugated fiberboard < 0.2 × corrugated height h.

[0026] Furthermore, the fragment spacing / fragment diameter ratio is ≥10.

[0027] Furthermore, the corrugated web width d = (0.9~1.0) × corrugated flange width b, and the corrugation height h = (0.9~1.0) × corrugated web width d.

[0028] Furthermore, the width of the corrugated web d = the width of the corrugated flange b = the height of the corrugations h.

[0029] Furthermore, the fiber is ultra-high molecular weight polyethylene fiber. More preferably, the molecular weight of the polyethylene fiber is 1.8 million to 3.8 million.

[0030] Furthermore, the fiberboard is obtained by laminating multiple layers of non-woven unidirectional fabric.

[0031] Example 1:

[0032] In this embodiment, the fragments are made of tungsten carbide alloy with a density of 16 g / m³. 3 The diameter is 6mm, and the minimum circumcircle diameter d of the three fragments is... iThe fragments are 220mm thick, and their impact velocity is set to 400m / s. The interlaced distributed corrugated fiber structure consists of positive and negative corrugations, each composed of 9 layers of ultra-high molecular weight polyethylene fiber (molecular weight of 3 million) non-woven unidirectional polyethylene fiber fabric, with each layer being 0.15mm thick. The number of units (n) in the corrugated fiber structure is 3, the unit span (m) is 160mm, the corrugated web width (d) is 40mm, the corrugated flange width (b) is 40mm, the corrugation height (h) is 40mm, and the unidirectional thickness (t) of the interlaced distributed corrugated fiber structure is 1.35mm. The minimum spacing (s) between any two fragments is 120mm. Figure 4 As shown.

[0033] Comparative Example 1: The impact conditions were the same as in Example 1. The flat fiber consisted of 20 layers, and its total mass was the same as that of the interlaced corrugated structure in Example 1.

[0034] Figure 5 Comparative Example 1: Traditional flat fiber ( Figure 5 (a1), (a2)) and the staggered distributed corrugated fiber structure of Example 1 ( Figure 5 Comparison of response morphologies of (b1) and (b2) after being impacted by fragments: Among them, the flat fiber has a limited in-plane fiber content, resulting in a large overlap of out-of-plane bulges caused by different fragments, which means that vicious competition between multiple fragments cannot be avoided, and fragment perforation is eventually formed; in contrast, the out-of-plane bulges of the interlaced distributed corrugated fiber structure after being impacted by different fragments are more dispersed, which means that more fibers are obtained for each fragment to participate in tensile interception, thus no fragment perforation is caused.

[0035] Within 0.8 ms after the impact, the Mises stress in Comparative Example 1 propagated extremely rapidly in the plane, forming an interwoven network distribution. Figure 6 In Example (a), its influence range is much larger than the high stress range corresponding to Example 1; in Example 1, the three-dimensional shape characteristics of the corrugations are used to hinder the propagation efficiency of stress between different corrugated elements, while also better protecting the constraint boundary ( Figure 6 (b) avoids the boundary tearing phenomenon that is easily caused by fragment impact on traditional flat fibers.

[0036] like Figure 7 As shown, the residual velocities of the fragments in Example 1 are all 0, achieving complete interception. Furthermore, the velocity curves of the three fragments are similar, and their effective energy absorption time is greater than 1 ms. This indicates that the interlaced distributed corrugated fiber structure provides high protection and stability against multiple fragments. Figure 7(b) In Comparative Example 1, the remaining velocities of the three fragments were 174 m / s, 115 m / s, and 174 m / s, respectively, all of which could not be intercepted. Furthermore, the velocity curves of the three fragments differed significantly, and their effective energy absorption time was less than 0.5 ms. This indicates that the traditional flat fiber has low protective efficacy and stability against multiple fragments. Figure 7 (a)

[0037] In summary, the invention includes, but is not limited to, the above embodiments. Any equivalent substitutions or partial improvements made under the spirit and principles of this invention shall be considered to be within the protection scope of this invention.

Claims

1. A staggered distributed corrugated fiber protective structure for intercepting multiple fragments, characterized in that: It includes an upper corrugated fiberboard and a lower corrugated fiberboard that are staggered. The two ends of the upper and lower corrugated fiberboards are in planar contact and fixed by a fixing structure. The cross-section of the upper corrugated fiberboard is trapezoidal, and the cross-section of the lower corrugated fiberboard is inverted trapezoidal. The cell structure dimensions of the upper and lower corrugated fiberboards are the same. The staggered distribution ensures that each fragment is intercepted by the corrugated web section and the corrugated flange section. Number of cells n × cell span m ≥ minimum circumcircle diameter d among multiple fragments i Cell span m ≥ minimum spacing s between two fragments, corrugated web width d = (0.8~1.2)×corrugated flange width b, corrugated height h = (0.6~1.0)×corrugated web width d, single-layer fiber thickness ≤ unidirectional thickness t of corrugated fiberboard < 0.2×corrugated height h.

2. The interlaced distributed corrugated fiber protective structure for intercepting multiple fragments as described in claim 1, characterized in that: The width of the corrugated web is d = (0.9~1.0) × the width of the corrugated flange b, and the height of the corrugation is h = (0.9~1.0) × the width of the corrugated web d.

3. The interlaced distributed corrugated fiber protective structure for intercepting multiple fragments as described in claim 1, characterized in that: The width of the corrugated web d = the width of the corrugated flange b = the height of the corrugation h.

4. The interlaced distributed corrugated fiber protective structure for intercepting multiple fragments as described in claim 1, characterized in that: The fiber is polyethylene fiber.

5. The interlaced distributed corrugated fiber protective structure for intercepting multiple fragments as described in claim 4, characterized in that: The molecular weight of the polyethylene fiber is 1.8 million to 3.8 million.

6. The interlaced distributed corrugated fiber protective structure for intercepting multiple fragments as described in claim 1, characterized in that: The fiberboard is obtained by laminating multiple layers of non-woven unidirectional fabric.

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