Composite impact-resistant material based on Budded oak bionic structure and application of composite impact-resistant material in helmet

Abstract

The invention discloses a composite impact-resistant material based on a Budded oak bionic structure and application of the composite impact-resistant material in a helmet, and belongs to the technical field of human body protection articles. The material comprises a buffer layer and a bionic structure layer, the bionic structure layer is composed of a bionic toughening layer and a bionic protective layer, and the bionic toughening layer and the bionic protective layer are laid according to a Budded oak bionic structure; and the bionic structure layer is formed by alternately laying organic polymer fibers by using thermosetting resin as an adhesive. The buffer layer is made of EPS foaming materials. The organic polymer fiber is Kevlar K-49, and the thermosetting resin is epoxy resin. The invention designs and develops a multilayer bionic impact-resistant material with a bionic impact-resistant surface layer, a bionic energy-absorbing transfer layer and a bionic toughening crack-arresting base layer based on a strength-toughness-rigidity synergistic interaction principle of a bionic composite material. The original single cloth stand bionic structure design is improved, and the impact resistance protection level of the bionic composite material is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of human body protection products, and in particular relates to a bionic multilayer bionic impact-resistant material designed based on the synergistic enhancement principle of strength-toughness-rigidity of bionic composite materials. Background Art

[0002] Data show that high-speed projectiles or fragments on the battlefield can cause about 80% of fatal injuries, of which 45% are on the head, and wearing bulletproof helmets can reduce the mortality rate by about 20%. Bulletproof helmets absorb and decompose the kinetic energy of projectiles or fragments, reduce penetration, prevent penetration, protect the heads of combatants, and improve the survivability of soldiers on the battlefield. They are one of the important equipment for individual combat.

[0003] In recent years, biomimetic-inspired materials have been developed to achieve unprecedented mechanical properties. Bouligand-type structures exist in various crustaceans, including mantis shrimp, coelacanth and crab exoskeletons, and the microstructures of these organisms' low-weight protective armor can provide ultra-high mechanical properties. The Bouligand structure consists of individual layers made of composite layers reinforced with unidirectional chitin fibrils, which are stacked in a spiral shape relative to the fiber orientation. The angle formed between two adjacent layers is the pitch angle. This bio-inspired spiral configuration has also been used to design composite metamaterials that have shown excellent performance in fracture toughness, ultimate strength, impact resistance and energy absorption. However, current Bouligand biomimetic helmets are mostly single applications of single or double helices. The single helix is ​​mainly used for impact energy absorption; the double helix structure can significantly improve the fracture toughness of the material due to its special configuration; if the two can be combined, the comprehensive mechanical properties of the material in extreme environments will be significantly improved; based on the synergistic principle of strong-tough-rigid bionic composite materials, the bionic multilayer bionic impact-resistant material is improved and designed, and applied to the outer shell of the helmet, which is conducive to improving the usability and strength of the helmet and providing full protection for soldiers in combat. To this end, the present invention is based on the ACH helmet structure and uses a new bionic composite material to improve it. Summary of the invention

[0004] The purpose of the present invention is to solve the above-mentioned problems existing in the background technology part and to provide a composite impact-resistant material based on the Brigan bionic structure and its application in a helmet.

[0005] Based on the synergistic enhancement principle of strength-toughness-rigidity of bionic composite materials, the present invention designs and develops an ultra-thin high-strength-toughness-rigid bionic helmet made of a multi-layer bionic impact-resistant material with a bionic impact-resistant surface layer, a bionic energy absorption and transfer layer, and a bionic toughening and crack arresting base layer.

[0006] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0007] A composite impact-resistant material based on a Brigan bionic structure, the material comprising a buffer layer and a bionic structure layer; the bionic structure layer consists of a bionic toughening layer and a bionic protective layer (the bionic toughening layer is adjacent to the buffer layer), the bionic toughening layer and the bionic protective layer are laid according to the Brigan bionic structure; the bionic structure layer is formed by alternately laying organic polymer fibers using a thermosetting resin as an adhesive, and the organic substrate units on the two adjacent bionic structure unit layers are all arranged in one direction.

[0008] Furthermore, the buffer layer is EPS foam material.

[0009] Furthermore, the buffer layer has a thickness of 10-15 mm.

[0010] Furthermore, the organic polymer fiber is Kevlar K-49, and the thermosetting resin is epoxy resin.

[0011] Furthermore, the thickness of a single layer of Kevlar K-49 does not exceed 0.20 mm.

[0012] Furthermore, the bionic structure layer is formed by laying out the unidirectional prepreg according to the Brigan bionic structure to obtain a preform, which is then hot-pressed in one step.

[0013] Furthermore, the bionic structure layers are all symmetrically laid.

[0014] Furthermore, the preform is laid according to a bionic configuration, and the bionic protective layer follows a single spiral laying: the angle between two adjacent substrate units is 10°, every 18 layers are one unit, and a total of 2 units are set; the bionic toughening layer follows a double spiral laying, that is, the adjacent odd-numbered substrate layers are orthogonal to the even-numbered substrate layers, the angle between two adjacent odd-numbered layers is 5°, every 36 layers are one unit, and a total of 1 unit is set.

[0015] An application of the composite impact-resistant material based on the Brigan bionic structure in a helmet, wherein the total thickness of the helmet body is 20-25 mm, and the surface density of the helmet body is ≤8 kg / m 2 .

[0016] The beneficial effects of the present invention compared with the prior art are as follows: based on the synergistic principle of strength-toughness-rigidity of bionic composite materials, the present invention designs and develops a multi-layer bionic impact-resistant material having a bionic impact-resistant surface layer, a bionic energy absorption and transfer layer, and a bionic toughening and crack-stopping base layer, and applies it to ACH helmets. The previous single Buligaon bionic structure design is improved, the impact protection level of bionic composite materials is improved, and the strength of the helmet is greatly increased while the surface density of the helmet is reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 is a schematic diagram of the pitch angle;

[0018] Figure 2 This is a structural diagram of a single spiral ply.

[0019] Figure 3 This is the structure diagram of the double spiral ply cloth;

[0020] Figure 4 For the control test of various isotropic materials;

[0021] Figure 5 The double helix group impact test setup and result diagram;

[0022] Figure 6 This is a schematic diagram of the helmet structure;

[0023] Figure 7 This is a research diagram of high-strength-toughness-rigidity bionic impact-resistant fiber composite materials;

[0024] Figure 8 Bilinear traction-separation relationship diagram of the CZM model. DETAILED DESCRIPTION

[0025] The technical solution of the present invention is further described below in conjunction with the accompanying drawings and embodiments, but is not limited thereto. Any modification or equivalent replacement of the technical solution of the present invention that does not depart from the spirit and scope of the technical solution of the present invention should be included in the protection scope of the present invention.

[0026] Based on the synergistic principle of strength-toughness-rigidity of bionic composite materials, the present invention improves the Buligaon bionic structure and designs an ultra-thin high-strength-toughness-rigid bionic helmet; first, the composite material ply adopts a gradient bionic structure design; single-helix small helix angle paving is selected to achieve energy absorption and impact resistance; double-helix small helix angle paving is selected to achieve toughening and crack arrest. In each unidirectional (UD) ply, fiber breakage and matrix cracking are considered through the 3D Ashin failure criterion and evolution law integrated in the ABAQUS / Explicit solver. The damage initiation and evolution values ​​used for the intra-layer damage model are listed in Table 1. For the inter-layer damage model, the ideal bilinear traction-separation softening cohesive zone model (CZM) based on the continuous damage mechanics theory is used to simulate the delamination damage between adjacent layers.

[0027] The repeated impact resistance of bionic Bouligand-type composite laminates was studied by combining experimental and numerical simulation methods. Bouligand-type and quasi-isotropic (QI)-type specimens were subjected to single impacts of 20, 30 and 40 Joules and five repeated impacts. The damage characteristics of all specimens were obtained by C-scan technology, and the influence of Bouligand structure on the impact energy absorption capacity was further studied using a three-dimensional finite element model.

[0028] Finally, after obtaining the optimal energy-absorbing single and double helix models, the helmet design is optimized, and the bionic helmet is modeled and simulated through the material's energy absorption evaluation function, design scheme optimization, etc. Based on the structure-function design scheme, the present invention selects the coupled Buligang bionic structural composite material, conducts simulation experiments, obtains impact response, and reveals the damage mechanism, providing reference and reference for the structural design and manufacturing of high-performance composite-coupled bulletproof helmets in the future.

[0029] Example 1

[0030] 1. By using ABAQUS / Explicit commercial software and symmetric boundary conditions, a 1 / 4-size physical model (75 mm × 50 mm) was created to improve computational efficiency. A 10 × 10 mm area was divided in the target area to increase the mesh density to improve the accuracy of the contact analysis. The hemispherical impactor was simulated using rigid body constraint properties, and the hammer was discretized for simulation (FE) using 4-node 3D solid elements with a total of 2397 elements. Each laminate was meshed by 8-node quadrilateral continuous shell elements (SC8R), and the mesh size in the impact area was set to 0.25 mm × 0.25 mm × 0.2 mm. The mesh density gradually decreased outward, and the maximum size did not exceed 1 mm to obtain converged results. The simulation results of the finite element model provided highly accurate residual velocity and energy absorption predictions for laminates with different stacking sequences.

[0031] 2. In each unidirectional (UD) laminate, fiber fracture and matrix cracking are considered by the 3D Hashin failure criterion and evolution law integrated in the ABAQUS / Explicit solver. The damage initiation and evolution values ​​for the intra-layer damage model are listed in Table 1. For the inter-layer damage model, the ideal bilinear traction-separation softening cohesive zone model (CZM) based on the continuum damage mechanics theory is used to simulate the delamination damage between adjacent layers, as shown in Figure 8 shown.

[0032] Table 1T700 / SYT49S-12K material properties

[0033]

[0034] Where: G It G represents the energy release rate of tensile failure in the opening mode; IIt G represents the energy release rate of tensile failure in sliding mode; Ic represents the critical energy release rate of the opening mode; G IIc represents the critical energy release rate of the sliding mode; the other direction refers to the plane whose outer normal is parallel to direction 2 and parallel to direction 3.

[0035] The constitutive relation in CZM (cohesive zone model) can be expressed as the following equation:

[0036]

[0037] The initiation of damage is predicted by using the secondary traction failure criterion:

[0038]

[0039] Among them, K ij Indicates the stiffness of the material in different directions, δ ii denote the displacement in the normal direction and two tangential directions, t ii is the traction force component, represents the critical traction force value, nn represents the normal direction, tt and ss represent two tangential directions respectively, and <> means that only tensile stress contributes to the damage.

[0040] Once the failure criterion is met, the initiation of interface damage is reached. The critical energy release rate G is calculated using the Benzeggagh and Kenane (BK) model combined with the evolution law. c and simulate interface degradation.

[0041]

[0042] Among them, G I represents the energy release rate of the opening mode; G II represents the energy release rate of the scratching mode; G III represents the energy release rate of the tearing mode; η represents an empirical parameter used to adjust the contribution of different modes to the total energy release rate.

[0043] 3. The sample was made by wet laying and vacuum bag process. Then the test bench was built to carry out impact test on the sample. The specific experimental settings are shown in Table 2 and Table 3. The maximum displacement, energy absorption ratio and other experimental data were collected by the sensors of the experimental equipment (such as Figure 4 ), and damage data was collected by C-scan. Under a single impact of 40 joules, the specific energy absorption (SEA) of the double-helix Bouligand configuration was approximately 20.3% and 12.7% higher than that of the QI and single-helix specimens, respectively, and exhibited obvious petal-like delamination characteristics, indicating that the bionic design method of the double helix can significantly improve the energy absorption capacity of CFRP laminates. At the same time, the double-helix configuration with a smaller pitch angle is superior to the configuration with a larger pitch angle in terms of energy absorption capacity and peak load. Under the same impact energy and impactor shape, for the 5° pitch angle specimen, as the impactor mass decreases, a more dispersed damage distribution can be obtained, thereby enhancing the impact resistance, such as Figure 4 and 5 shown.

[0044] Table 2 shows the 10°, 20° single and double helix angles and various quasi-isotropic laminates

[0045] abbreviation Stacking method Pitch angle (°) Stacking angle (°) Thickness(mm) QI Quasi-isotropic 45 <![CDATA[[0 / 45 / 90 / 135 / 0] 2s ]]> 4 B10 Single-twisted Bouligand 10 [0 / 10 / … / 90 / 90 / … / 170 / 180] 4 B20 Single-twisted Bouligand 20 <![CDATA[[0 / 20 / 40 / … / 160 / 180] s ]]> 4 D10 Double-twisted Bouligand 10 [0 / 90 / 10 / 100 / … / 90 / 180] 4 D20 Double-twisted Bouligand 20 <![CDATA[[0 / 100 / 20 / 120… / 90 / 180] s ]]> 4

[0046] Table 3 shows the settings for 5°, 10°, and 22.5° double helix angle laminates

[0047]

[0048] 4. A helmet model was established by constructing a sensitivity analysis of design parameters. Based on the ACH helmet model, the properties of the single and double helix coupled Burigang high-strength-toughness-rigid bionic material obtained in the above experimental study were applied. The bullet size was set to 7.62mm and the impact speed was set to 840m / s for a simulation experiment.

[0049] 5. According to the ACH helmet model ( Figure 6 ) is shown in the figure, and a helmet is prepared according to the claims.

[0050] Example 2

[0051] A composite impact-resistant material based on a Brigan bionic structure, the material comprising a buffer layer and a bionic structure layer; the bionic structure layer consists of a bionic toughening layer and a bionic protective layer (the bionic toughening layer is adjacent to the buffer layer), the bionic toughening layer and the bionic protective layer are laid according to the Brigan bionic structure; the bionic structure layer is formed by alternately laying organic polymer fibers using a thermosetting resin as an adhesive.

[0052] The buffer layer is made of EPS foam material with a thickness of 12-14 mm.

[0053] The organic polymer fiber is Kevlar K-49, and the thermosetting resin is epoxy resin. The thickness of a single layer of Kevlar K-49 is 0.18 mm.

[0054] The bionic structure layer is formed by laying out the unidirectional prepreg according to the Brigan bionic structure to obtain a preform, which is hot pressed once. The bionic structure layer is symmetrically laid out.

[0055] The preform is laid according to the bionic configuration, and the bionic protective layer follows the single spiral laying: the angle between two adjacent substrate units is 10°, every 18 layers are one unit, and a total of 2 units are set; the bionic toughening layer follows the double spiral laying, that is, the adjacent odd-numbered substrate layers are orthogonal to the even-numbered substrate layers, the angle between two adjacent odd-numbered layers is 5°, every 36 layers are one unit, and a total of 1 unit is set.

[0056] An application of the composite impact-resistant material based on the Brigan bionic structure in a helmet, wherein the total thickness of the helmet body is 20-25 mm, and the surface density of the helmet body is ≤8 kg / m 2 .

Claims

1. A composite impact-resistant material based on the Brigan bionic structure, characterized in that: The material includes a buffer layer and a bionic structure layer; the bionic structure layer consists of a bionic toughening layer and a bionic protective layer (the bionic toughening layer is adjacent to the buffer layer), and the bionic toughening layer and the bionic protective layer are laid according to the Brigan bionic structure; the bionic structure layer is formed by alternately laying organic polymer fibers using thermosetting resin as an adhesive.

2. The composite impact-resistant material based on the Brigan bionic structure according to claim 1, characterized in that: The buffer layer is EPS foam material.

3. The composite impact-resistant material based on the Brigan bionic structure according to claim 1, characterized in that: The thickness of the buffer layer is 10-15 mm.

4. The composite impact-resistant material based on the Brigan bionic structure according to claim 1, characterized in that: The organic polymer fiber is Kevlar K-49, and the thermosetting resin is epoxy resin.

5. The composite impact-resistant material based on the Brigan bionic structure according to claim 3 is characterized in that: The thickness of a single layer of Kevlar K-49 does not exceed 0.20mm.

6. The composite impact-resistant material based on the Brigan bionic structure according to any one of claims 1 to 5, characterized in that: The bionic structure layer is formed by laying out unidirectional prepreg according to the Brigan bionic structure to obtain a preform, which is hot-pressed in one step.

7. The composite impact-resistant material based on the Brigan bionic structure according to claim 1, characterized in that: The bionic structure layers are all symmetrically laid.

8. The composite impact-resistant material based on the Brigan bionic structure according to claim 1 or 6, characterized in that: The preform is laid according to the bionic configuration, and the bionic protective layer follows the single spiral laying: the angle between two adjacent substrate units is 10°, every 18 layers are one unit, and a total of 2 units are set; the bionic toughening layer follows the double spiral laying, that is, the adjacent odd-numbered substrate layers are orthogonal to the even-numbered substrate layers, the angle between two adjacent odd-numbered layers is 5°, every 36 layers are one unit, and a total of 1 unit is set.

9. Application of the composite impact-resistant material based on the Brigan bionic structure according to any one of claims 1 to 8 in a helmet, characterized in that: The total thickness of the helmet body is 20-25 mm, and the surface density of the helmet body is ≤8 kg / m 2 .

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