Multi-Scale Numerical Simulation Of Anti-Penetration Performance Of Fiber Reinforced Composites

The production of armor has existed since ancient times.Among the many kinds of armor made by the ancients,paper armor and silk armor,which are made of fiber-reinforced composite materials,are still vital in today’s era when weapons become more and more lethal,and have become a hot research topic in many countries.In order to further understand the bullet-proof mechanism of fiber reinforced composites,understand the influence of interface in fiber reinforced composites on anti-penetration performance,and develop bullet-proof composites with higher performance,in this paper a multi-scale numerical model of carbon fiber composites is established,and the micro,meso,macro multi-scale simulation research is carried out.The parameters were transferred between different scales.The corresponding relationship between microstructure and macroscopic was established to find the best interface bonding performance between carbon fiber and resin under the bullet penetration.At the micro-level,the acquisition of interface parameters is realized.At the meso-level,the meso-simulation of projectile impact and the optimization of interface parameters are realized.At the macro-level,the simulation research on the anti-penetration performance of laminate angle is realized,and the anti-penetration simulation research of carbon fiber reinforced composite is achieved.The results of molecular dynamics simulation on the micro-scale show that the tensile/shear rate and the thickness of the confinement layer have a great influence on the interfacial properties of carbon fiber/polyethylene,and both of them affect the interfacial properties by affecting the free responding layer of resin.With the increase of the tensile/shear rate and the thick of confinement layer,the interfacial bonding strength increased.With the increase of temperature,the lower the interfacial bonding strength is.At the same time,the interfacial tensille/shear properties under different grafting ratios of hydroxyl and amino groups were also studied.The meso impact model of carbon fiber/polyethylene was established,and the interface parameters obtained from micro simulation were transferred to the cohesive element material parameter in the micro model to simulate the anti-penetration performance under different interface properties.It is found that the effect of meso impact on fiber/resin composites is locality,and the stress is mainly distributed along the fiber.The damage modes include fiber fracture,matrix crack and interface debonding.Under the impact of the projectile,the interfacial debonding mainly occurs on the fiber directly impacted by the projectile.There is a large damage in the center of the fiber,which indicates that the fiber buckling is also a mode of interface damage when the fiber is impacted by the projectile.The results show that the energy absorption of the target increases first and then decreases with the grafting of hydroxyl group,and the maximum energy absorption is obtained when the grafting ratio of hydroxyl group is 1.43/nm2.The anti-penetration performance of the target does not increase with the increase of the interface bonding strength.With the increase of impact velocity,the energy absorption ratio of the target decreases gradually.The numerical model of anti-penetration performance of ceramic/fiber composite armor is established,and the experimental study is carried out.The simulation results are in good agreement with the experimental results.The meso model was used as RVE to get the material parameters of the macro carbon fiber laminate.The simulation and optimization of the fiber ply angle and different ceramic types/thickness were carried out,and the best fiber ply angle was found.It was found that the reasonable use of 45 °layer would increase the bullet-proof performance of the fiberboard.The bullet-proof performance will be best when using the B₄C ceramic with the thickness of 10mm.