Lightweight bionic discontinuous fiber spiral composite protection structure

Abstract

The invention relates to a light bionic discontinuous fiber spiral composite protection structure, and belongs to the technical field of light protection structure design. The light, high-strength and high-toughness bionic discontinuous fiber spiral composite protection structure is formed by stacking unit discontinuous fiber fabrics according to different arrangement angles and arrangement modes, under the condition that local stress concentration in layers is relieved, shear stress is distributed to discontinuous connecting parts in all the layers, the concentration of interlayer shear stress is relieved, and the stability of the protection structure is improved. By means of an in-layer tensile stress and interlayer shear stress distribution mechanism of the composite material, cracks frequently deflect when the composite material bears loads, failure and damage of the material can be delayed, and the bearing capacity and the energy absorption capacity of the composite protection structure are greatly improved.

Description

Technical Field

[0001] The invention relates to a lightweight bionic discontinuous fiber spiral composite protective structure, belonging to the technical field of lightweight protective structure design. Background Art

[0002] In modern science and engineering applications, the demand for high-performance protective structures in the fields of military protection, aerospace, rail transportation and special equipment manufacturing is becoming increasingly urgent. Equipment and personnel in these fields often face extremely dangerous situations such as high-speed impact, collision and explosion, so the protective structure is required to be lightweight, high-strength, high-toughness and excellent energy absorption characteristics. Traditional protective structures mainly use metal materials (such as steel, aluminum alloy) and single polymer materials. Although metal materials have high strength, they have high density, which makes the protection system too heavy, and it is easy to produce stress concentration and local damage when dealing with high-speed impact, and it is impossible to effectively absorb and dissipate impact energy. Although the density of polymer materials is relatively small, it is difficult for a single polymer material to meet the high-strength protection requirements in terms of strength and toughness, and its structural stability and durability are poor. Summary of the invention

[0003] The technical problem solved by the invention is: to overcome the deficiencies of the prior art and to provide a lightweight bionic discontinuous fiber spiral composite protective structure.

[0004] The technical solution of the present invention is:

[0005] A lightweight bionic discontinuous fiber spiral composite protective structure, the composite protective structure is formed by stacking several layers of unit discontinuous fiber fabrics, and the adjacent layers are rotated at a set angle in a set direction;

[0006] The unit discontinuous fiber fabric is composed of more than one layer of single-layer discontinuous fiber fabric;

[0007] The shearing positions of adjacent single-layer discontinuous fiber fabrics are staggered by the same distance; the staggered distance is any distance that the single-layer discontinuous fiber fabric can withstand within the surface;

[0008] If the unit discontinuous fiber fabric is composed of more than two layers of single-layer discontinuous fiber fabrics in a way that the shearing lines do not overlap, it is required that the shearing positions cannot all overlap;

[0009] The single-layer discontinuous fiber fabric is composed of unidirectional continuous fibers and polymers. The continuous fibers are discontinuous by shearing, and the shearing direction is not parallel to the unidirectional fiber direction.

[0010] Beneficial Effects

[0011] (1) The single-layer discontinuous fiber fabric of the present invention is different from the conventional single-layer continuous fiber fabric in that the fibers are discontinuous, which can effectively alleviate the local stress concentration within the layer;

[0012] (2) The unit discontinuous fiber fabric of the present invention is composed of more than one layer of single-layer discontinuous fiber fabric, which can effectively alleviate the local stress concentration in the layer on the basis of the single-layer discontinuous fiber fabric, and at the same time improve the toughness and energy absorption characteristics of the protective structure;

[0013] (3) The lightweight, high-strength and high-toughness bionic discontinuous fiber spiral composite protective structure of the present invention is formed by stacking unit discontinuous fiber fabrics according to different arrangement angles and arrangement methods. While effectively alleviating the local stress concentration within the layer, the shear stress is distributed to the discontinuous connecting parts within each layer, thereby alleviating the concentration of shear stress between layers. The intra-layer tensile stress and inter-layer shear stress distribution mechanism of the composite material is utilized to make the cracks deflect frequently when it is subjected to load, which can delay the failure of the material and greatly improve the load-bearing and energy absorption capacity of the composite material. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a schematic diagram of a unit discontinuous fiber fabric composed of 1 layer of single-layer discontinuous fiber fabric;

[0015] Figure 2 It is a schematic diagram of a unit discontinuous fiber fabric composed of three layers of single-layer discontinuous fiber fabrics;

[0016] Figure 3 It is a schematic diagram of a unit discontinuous fiber fabric composed of 5 layers of single-layer discontinuous fiber fabrics;

[0017] Figure 4 It is a schematic diagram of stacking unit discontinuous fiber fabrics according to different interlayer rotation angles and arrangements;

[0018] Figure 5 for Figure 4 Schematic diagram when θ1=θ2=θ3=……=45°;

[0019] Figure 6 for Figure 4 Schematic diagram when θ1=θ2=θ3=……=90°;

[0020] Figure 7 It is a schematic diagram of the unit discontinuous fiber fabric being laid layer by layer with an interlayer rotation angle θ=15°. DETAILED DESCRIPTION

[0021] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0022] Example

[0023] A lightweight bionic discontinuous fiber spiral composite protective structure, by laying discontinuous fibers at a set spiral angle, can not only fully utilize its lightweight advantage, but also use the bionic structure to optimize the mechanical properties within and between layers, effectively improve the energy absorption and dissipation efficiency of the protective structure when facing high-speed impact, significantly enhance the overall protective performance, and provide innovative solutions for the protection needs of key fields such as military, aerospace, etc.

[0024] The light-weight, high-strength, and high-toughness protective structure of the present invention can reduce the weight of the protective system while improving the impact resistance and energy absorption performance. By optimizing the arrangement of discontinuous fibers, the synergistic improvement of the mechanical properties within and between layers is achieved. The defects of the existing continuous fiber spiral laminated structure in stress concentration, interface bonding, and stress transfer under impact loads are overcome, and the comprehensive protective performance and durability of the material are significantly improved. The special needs of military protection, aerospace and other fields under extreme conditions such as high-speed impact and collision are met, and the development and application of protective structure technology are promoted.

[0025] The present invention provides a lightweight bionic discontinuous fiber spiral composite protective structure. Multiple layers of discontinuous fiber fabrics are stacked and arranged in different ways and at different angles. In the composite material, the tensile stress in the single-layer discontinuous fiber is discontinuously distributed when subjected to load, which can effectively alleviate the local stress concentration in the layer; the layers are arranged at different angles to distribute the interlayer shear stress to the discontinuous connecting parts in each layer, thereby alleviating the concentration of interlayer shear stress. The intralayer tensile stress and interlayer shear stress distribution mechanism of the composite material allows the cracks to deflect frequently when subjected to load, which can delay the failure of the material and greatly improve the load-bearing and energy absorption capacity of the composite material.

[0026] Single-layer discontinuous fiber fabrics are composed of unidirectional fibers and polymers, and the continuous fibers are interrupted by shearing. Figure 1 FIG. 1 is a schematic diagram of a specific example of a single-layer discontinuous fiber fabric, wherein the unidirectional fiber direction is along the X direction in the figure, and the shear direction is along the Y direction in the figure. In the actual implementation process, the shear direction is not parallel to the unidirectional fiber direction.

[0027] The unit discontinuous fiber fabric is composed of one or more layers of single-layer discontinuous fiber fabric.

[0028] Figure 1 An example diagram of a unit discontinuous fiber fabric consisting of 1 layer of single-layer discontinuous fiber fabric is given;

[0029] Figure 2 An example diagram of a unit discontinuous fiber fabric consisting of three layers of single-layer discontinuous fiber fabric is given;

[0030] Figure 3An example diagram of a unit discontinuous fiber fabric consisting of 5 layers of single-layer discontinuous fiber fabric is given;

[0031] exist Figure 2 and Figure 3 In the method, the shearing positions of each adjacent layer of the single-layer discontinuous fiber fabric are staggered by the same distance.

[0032] The shearing positions between adjacent and non-adjacent layers can be the same or different, and the staggered distance can be any distance that can be tolerated within the surface of a single-layer discontinuous fiber fabric.

[0033] If the unit discontinuous fiber fabric is composed of two or more layers of single-layer discontinuous fiber fabrics in a way that the shearing lines do not overlap, it is required that the shearing positions cannot all overlap.

[0034] The lightweight, high-strength and high-toughness bionic discontinuous fiber spiral composite protective structure material is composed of unit discontinuous fiber fabrics stacked according to different layer rotation angles and arrangements. Figure 4 The figure shows an example of a lightweight, high-strength and high-toughness bionic discontinuous fiber spiral composite protective structure material, where θ1, θ2, θ3, ... are the angles between adjacent unit discontinuous fiber fabrics, and the angles can be any value.

[0035] Figure 5 and Figure 6 These are two other examples of lightweight, high-strength and high-toughness biomimetic discontinuous fiber spiral composite protective structural materials. Figure 5 in, θ1=θ2=θ3=……=45°; in Figure 6 In, θ1=θ2=θ3=……=90°.

[0036] Single-layer discontinuous fiber fabrics are different from previous single-layer continuous fiber fabrics. Their characteristics are that the fibers are discontinuous, which can effectively alleviate the local stress concentration within the layer; unit discontinuous fiber fabrics are characterized by being composed of one or more layers of single-layer discontinuous fiber fabrics, which can maintain and alleviate the local stress concentration within the layer on the basis of single-layer discontinuous fiber fabrics; lightweight, high-strength, high-toughness bionic discontinuous fiber spiral composite protective structure materials are characterized by being stacked according to different arrangement angles and arrangement methods of unit discontinuous fiber fabrics. While alleviating the local stress concentration within the layer, the shear stress is distributed to the discontinuous connection parts within each layer, alleviating the concentration of shear stress between layers. The intra-layer tensile stress and inter-layer shear stress distribution mechanism of the composite material makes it possible for the cracks to deflect frequently when it is subjected to load, which can delay the failure of the material and greatly improve the load-bearing and energy absorption capacity of the composite material. Single-layer discontinuous fiber fabrics and unit discontinuous fiber fabrics can effectively alleviate local stress concentration within the layer due to the presence of broken fibers; the lightweight, high-strength, high-toughness bionic discontinuous fiber spiral composite protective structure material formed by stacking unit discontinuous fiber fabrics according to different arrangement angles and arrangement methods can distribute shear stress to the discontinuous connecting parts within each layer due to its certain arrangement angles and arrangement methods, thereby alleviating the concentration of shear stress between layers. The intra-layer tensile stress and inter-layer shear stress distribution mechanism of the composite material causes frequent crack deflection when it is subjected to load, which can delay material failure and damage, and greatly improve the load-bearing and energy absorption capacity of the composite material.

[0037] Example

[0038] This embodiment provides a lightweight bionic discontinuous fiber spiral composite protective structure. It can reduce the weight of the protective structure while having high strength, high toughness and excellent energy absorption characteristics. Figure 4 shown.

[0039] In this embodiment, the material of the lightweight bionic discontinuous fiber spiral composite protection structure is T700 unidirectional carbon fiber prepreg with a single layer thickness of 0.1 mm;

[0040] In this embodiment, the T700 unidirectional carbon fiber prepreg is cut into a square with a side length of L, where L=140 mm;

[0041] In this embodiment, a square unidirectional carbon fiber prepreg with a side length of L is prepared as follows: Figure 7 The 2 sizes shown are cut into discontinuous fiber thin (a), (b);

[0042] In this embodiment, the discontinuous fiber thin (a), (b) is pressed Figure 7 The structure shown in is staggeredly laid to obtain a unit discontinuous fiber fabric, each unit discontinuous fiber fabric consists of 2 layers (a) and 1 layer (b);

[0043] In this embodiment, the lightweight bionic discontinuous fiber spiral composite protection structure has 75 layers with a total thickness of 7.5 mm;

[0044] In this embodiment, the unit discontinuous fiber fabric is laid layer by layer in a rotation manner with an angle θ between adjacent layers of 15°. Figure 7 As shown, the sample was prepared by high temperature hot pressing and curing.

[0045] The prepared bionic discontinuous fiber spiral composite protective structure specimens were subjected to static compression bending mechanical property tests on an Instron 5544 material tension and compression testing machine. The experimental process and settings were similar to ASTM D6264. The results show that the hierarchical composite material with both "brick-mud" staggered laminated structure and spiral laminated structure has improved load-bearing capacity and energy absorption, which is closely related to the discontinuous fiber structure within the layer. The discontinuous distribution of tensile stress within the layer effectively alleviates the local stress concentration within the layer and delays material failure. At the same time, this "interlayer discontinuity-interlayer spiral" structure distributes the interlayer shear stress to the discontinuous connection parts within each layer, alleviating the concentration of interlayer shear stress. These mechanisms will have an important impact on the load-bearing and energy absorption of the structure. The combination of the two biological structures has positive significance for the design and performance optimization of lightweight structural materials, and is expected to be applied in aerospace, new energy and other fields.

[0046] In summary, the above are only preferred embodiments of the present invention and are not intended to limit the protection scope of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A lightweight bionic discontinuous fiber spiral composite protective structure, characterized by: The composite protective structure is formed by stacking a plurality of layers of unit discontinuous fiber fabrics, and adjacent layers are rotated at a set angle in a set direction.

2. The lightweight bionic discontinuous fiber spiral composite protective structure according to claim 1, characterized in that: The unit discontinuous fiber fabric is composed of more than one layer of single-layer discontinuous fiber fabric.

3. The lightweight bionic discontinuous fiber spiral composite protective structure according to claim 1, characterized in that: The shearing positions of adjacent single-layer discontinuous fiber fabrics are staggered by the same distance.

4. The lightweight bionic discontinuous fiber spiral composite protective structure according to claim 3, characterized in that: The staggered distance is any distance that can be tolerated within the surface of a single-layer discontinuous fiber fabric.

5. The lightweight bionic discontinuous fiber spiral composite protective structure according to claim 1, characterized in that: The unit discontinuous fiber fabric is composed of more than two layers of single-layer discontinuous fiber fabrics in a way that the shear lines do not overlap, and it is required that the shear positions cannot all overlap.

6. The lightweight bionic discontinuous fiber spiral composite protective structure according to claim 1, characterized in that: The single-layer discontinuous fiber fabric is composed of unidirectional continuous fibers and polymers. The continuous fibers are discontinuous by shearing, and the shearing direction is not parallel to the unidirectional fiber direction.

7. The lightweight bionic discontinuous fiber spiral composite protective structure according to claim 1, characterized in that: Adjacent layers in the composite protective structure are rotated 45 degrees in the same direction.

8. The lightweight bionic discontinuous fiber spiral composite protective structure according to claim 1, characterized in that: Adjacent layers in the composite protective structure are rotated 90° in the same direction.

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