Numerical Simulation Of Projectile Impact On Honeycomb Aluminum Waveform And Waveform Optimization Design

Based on the National Pre-Research Foundation of China,to cope with the difficulties of simulating a large energy impact test environment under high overload and wide pulse,numerical simulations of impact waveform are studied with an air gun providing initial velocity of a projectile and honeycomb aluminum receiving and buffering the projectile.The out-of-plane mechanical properties of honeycomb aluminum is analyzed.A model with a projectile penetrating honeycomb aluminum is established through LS-DYNA to simulate the process of penetration waveform.The penetration resistance against the projectile during the impact process is theoretically calculated,and the influence of different velocity of the projectile on penetration depth is studied.The finite element results are compared with the theoretical results which verify the validity of the finite element model.Through the simulation under different working conditions,the influences of different parameters on impulse response are compared including relative density and cell wall angle of aluminum honeycomb,and initial velocity and shape of the projectile.The results show that the relative density,cell wall angle,initial velocity have a great effect on the acceleration peak and pulse width,as well as the projectile shape has a great effect on impact wave shape.With the full parameter testing,three frequently-used approximation models are compared.EBF and the optimization strategy combining ASA with LSGRG are employed to optimize the impact peak and pulse width whose optimized results meet the standard.Based on series honeycomb structure,a model with a projectile penetrating honeycomb aluminum sandwich panels is established to simulate the impact process of the sandwich plate.The energy absorption properties of honeycomb sheets and honeycomb core are compared.The research indicates that the impact load is increased with thickening of honeycomb sheets.On the premise of appropriate sheet thickness and the honeycomb core density as design variable,a design method of shock wave based on series honeycomb structure is proposed.By this method,a half-sine shock wave satisfying the tolerance criterion is obtained.The results of this paper have significant references to the design of impact devices with honeycomb aluminum as buffer materials and the selection of impact test parameters.