Study On The Anti-Bullet Property Properties Of Carbon Fiber Composites

Carbon fiber composites have excellent physical and chemical properties and are widely used in aerospace and defense military fields.Compared with metal materials,carbon fiber composites are still relatively weak in related research due to their anisotropy,non-uniformity caused by multi-phase structure of materials and complex damage modes.In this paper,the penetration test and the numerical method are combined with the theoretical model to study the ballistic performance of carbon fiber composite materials for the case of cuboid fragments as damage elements.In this paper,the ballistic penetration test of fragment penetrating carbon fiber composite material is carried out.The ballistic limit and failure mechanism of steel fragment and tungsten fragment penetrating 6mm,10 mm and 14 mm carbon fiber composite material are studied when the penetration angle is 0°,30° and 45°.Through the analysis of the test results,the research shows that the failure mechanism of the surface fiber of the carbon fiber composite laminate is basically the same,mainly shear failure.The failure mechanism of the perforation tunnel and the back elastic surface of the fragment changes with the increase of the speed.The greater the speed,the greater the proportion of shear failure of the fiber material.When the speed is low,the carbon fiber composite material will have matrix delamination,fiber tensile failure,fiber tearing and other failure forms.When the fragment penetrates the carbon fiber composite laminate at a certain angle,the velocity projection direction of the laminate will be subjected to additional compression force,and the opposite direction will be subjected to additional tensile force,resulting in different failure modes in the velocity projection direction and the opposite direction.Based on the ballistic test,the numerical simulation of fragment penetrating carbon fiber composite material is carried out by establishing the numerical simulation model corresponding to the test.The established numerical simulation model can well reproduce the penetration process of fragment penetrating target plate.Based on the residual velocity obtained by numerical simulation under different working conditions,the residual velocity formula based on THOR equation is established,and the ballistic limit calculation formula is derived.The research shows that the process of fragment penetrating the target plate can be divided into the contact and stress wave propagation stage,the damage stage of the fragment to the target plate,and the subsequent penetration stage of the fragment to the target plate.The duration of the first stage is mainly related to the thickness of the target plate,and the duration of the second and third stages is related to the impact velocity and penetration angle of the fragment.Based on the results of ballistic test and numerical simulation,the theoretical study of fragment impact on carbon fiber composites was carried out.The response of carbon fiber composite laminates under high-speed impact and the failure mechanism of laminates were analyzed.The main energy loss in the process of fragment penetrating carbon fiber composite material is analyzed,and the relationship between different types of energy loss and fragment impact parameters and mechanical properties of carbon fiber composite laminates is obtained.The results show that under the load of high-speed impact,the stress wave of carbon fiber composites will diffuse around the center of the fragment impact area,and the response of the laminate will decrease with the increase of the distance from the impact position.After being impacted,carbon fiber composite laminates absorb the kinetic energy of fragments in various forms.The main forms of energy absorption are : kinetic energy and strain energy in the deformation zone caused by impact,fiber bundle fracture energy required for fiber layer failure of carbon fiber composite laminates,and energy absorbed by delamination damage and matrix cracking.