Research On High Speed Impact Damage And Numerical Simulation Of Structural Biomimetic Fiber Reinforced Composites

Fiber-reinforced composite have been common used in aerospace,rail transit,protective armor and other fields due to their high strength,light weight,and excellent comprehensive mechanical properties and impact resistance.In this paper,ultra-high molecular weight polyethylene(UHMWPE)fibers and Kevlar(Kevlar)fibers,which are used in protective armor design and are sensitive to strain rate,are selected as the research objects.Using the idea of structural biomimicry,by studying the biological tissue structures with excellent mechanical properties such as mantis shrimp claw sticks and shellfish in nature,and applying these structures to the molding design of fiberreinforced composite materials.And then,the dynamic mechanical performance test of structural biomimetic fiber reinforced composite materials and the ballistic performance test of fragments penetrating different biomimetic structural fiber reinforced composite materials were carried out.Finally,finite element simulation was used to analyze the high-speed impact resistance of structural bionic fiber reinforced composite materials and predict damage.The major research result of this article were shown as follows.According to the principle of biomimetic design,the helical structure of the periodic region of the mantis shrimp claw and the gradient structure of the shellfish biological tissue were applied to the forming and manufacturing of fiber-reinforced composite materials,respectively.The reinforced laminate was subjected to dynamic tensile,dynamic compression and dynamic shear mechanical performance tests,and its damage and failure morphology was analyzed.The results show that both UHMWPE fibers and Kevlar fibers are strain rate sensitive materials,and their peak stress varies with the strain.promote with the increase of the rate.The helical structure and the gradient structure will have a significant impact on the properties of the material.The tensile strength of the gradient hybrid structure sample is generally higher than that of the single-component material sample,and increases with the number of UHMWPE fiber layers.There will be a slight drop in performance.The tensile strength of the helical structure specimens is slightly lower than that of the orthogonal structure specimens,but the shear and compressive performance are better than those of the orthogonal structure specimens,and increase with the decrease of the helical lay-up angle.And then through the damage morphology analysis,it was found that when the sample was subjected to high-speed impact load,the fibers mainly occurred in the form of matrix squeezing,fiber fracture and fiber delamination.Inspired by the inner helical structure of the mantis shrimp claw,the antipenetration performance of the bionic helical UHMWPE fiber and the Kevlar fiber target plate was studied,and the high-speed fragment penetration test was carried out.The test results show that the target plate with the orthogonal structure has the highest ballistic limit performance,which is 10.2%-16.2% higher than that of the target plate with the bionic helical structure.Compared with the target plate of the orthogonal structure,the target plate of the helical structure can evenly transmit the impact force to each fiber direction when penetrating,absorb the impact force caused by the diffusion fragment,and make the occurrence of damage and the expansion of the crack more difficult.In addition,the injure deformation of the composite is reduced,and the damage deformation of the target plate is reduced by 48%-61% compared with the orthogonal structure target plate.Inspired by the bio-gradient structure of shellfish,the anti-penetration performance of UHMWPE fiber and Kevlar fiber hybrid target with different hybrid ratios was studied.From the analysis of the results after the ballistic penetration test,it can be seen that the target ballistic limit performance of the hybrid structure varies with the increase of UHMWPE fiber ratio,when K:U is 1:2,the target plate has the highest ballistic limit performance,and its damage deformation is more serious.Kevlar fiber can reduce the damage deformation and also reduce the ballistic limit.performance.And then,the impact of different penetrations on the ballistic resistance mechanism and ballistic limit performance of the hybrid composite target plate under the same hybrid ratio was studied.Using ABAQUS finite element analysis software and VUMAT material user subroutine to establish the dynamic penetration finite element model of the structural bionic composite target plate,and introducing the Cohesive interface element to simulate the interlayer delamination phenomenon of the target plate in the process of ballistic penetration,combined with three-dimensional Hashin failure criterion,simulates the damage process of composite laminates at high speed impact,and uses numerical analysis to deeply discuss the mutual synergistic effect between different structures and their influence on ballistic performance and damage characteristics.The finite element simulation results are in good agreement with the penetration test results,which provides a reference value for the design and application of new structural protective armor.