Molecular Dynamics Simulation Of Impact Behavior Of Graphene Reinforced Composites

Graphene-reinforced composites are often subjected to various impacts during daily production,operation and maintenance,and the design of protective materials with high penetration resistance has become a hot topic of research.According to the impact speed,the impact process can be divided into low-speed impact and high-speed impact,and there are relatively more studies on low-speed impact,but few studies on high-speed impact.In the process of high speed impact,the impact speed is fast and the time is very short,and it is difficult to observe the evolution of the microstructure of the material during the impact process by nanoscale test,and it is difficult to test the impact test due to the harsh test conditions and high experimental cost,so the high speed impact process can be studied by computer simulation.In this paper,the behavior of projectile impact on different graphene-reinforced composite structural systems(graphene/epoxy resin structural system and epoxy resin/graphene/epoxy resin structural system)is investigated by using molecular dynamics simulation(MD)to analyze the microscopic damage evolution mechanism of graphene-reinforced composites during the impact process.The main research of this paper is as follows:In this paper,we constructed the models of projectile impact graphene/epoxy resin and epoxy resin/graphene/epoxy resin,and simulated the impact behavior by applying different initial velocities(10,20,30,40,50,60 km/s)to the projectile,and studied the mechanical behavior of graphene-reinforced composites when impacted by the projectile,analyzed the velocity,displacement,kinetic energy,resistance with time,the relative change value of potential energy(VPE)of graphene in the target model,the temperature change of graphene and epoxy resin,the conversion of potential energy,kinetic energy and total energy in the simulated system,the bond breaking of graphene and the final structure of the model,the results of the study showed that:(1)When the projectile velocity is small(10,20,30 km/s),all fail to penetrate the target model of graphene/epoxy,epoxy/graphene/epoxy,and finally stay in the target model and move with the target model;when the projectile velocity is larger(40,50,60 km/s),the projectile completely penetrates the target model and continues to move downward,the larger the initial velocity of the projectile,the more the projectile is subjected to The greater the initial velocity of the projectile,the greater the resistance to the projectile,and the greater the remaining velocity when it finally passes through the target model,7.18,13.48,36.97 km/s(graphene/epoxy),5.41,17.31,40.55 km/s(epoxy/graphene/epoxy),respectively.(2)When the projectile impacts the target model,some of the chemical bonds of graphene will break and absorb a certain amount of impact energy,which makes the relative change value of potential energy of graphene increase,and the greater the impact velocity of the projectile,the more the VPE of graphene increases.When graphene/epoxy is used as the target model,the VPE peaks of graphene at 10,20,30,40,50,and 60 km/s are 3927.08,5372.89,8064.05,6879.69,7134.53,and 8060.96 Kcal/mol,respectively;when epoxy/graphene/epoxy is used as the target model,the The peak VPE of graphene at 10,20,30,40,50,and 60 km/s are 0,1059,5684,10638,12195,and 11705 Kcal/mol,respectively.(3)During the impact process,the temperature around the impact point of the projectile will increase due to frictional heat generation.When the projectile impacts the target model,some of the chemical bonds of the epoxy resin will be broken,forming irrecoverable "holes" inside the target model.During the whole impact process,the kinetic and potential energy of the projectile decreases and the kinetic and potential energy of the target model increases,and the energy is always conserved.