Simulation Of Projectile Penetrating Moving Target Based On Material Point Method

Projectile penetration and armor protection are a key issue in the military field.The reliable prediction of penetration effect and the improvement of penetrating ability are the research core for conventional weapons.The effect of the low velocity or high velocity movement of the object(the ship,tanks,cars,aircraft et.al.)on penetration ability,damage efficiency and posture of projectile is great.Projectile penetration is a very complex physical process.The large deformation,broken,fracture and so on is taken place under strong impact load,which has brought great challenges for numerical simulation.Material point method is a new meshless method.It has both the advantages of Euler and Lagrangian method.Finite element grid distortion is avoided in dealing with large deformation,discontinuity problems,material damage and fracture and so on.The process of projectile penetrating moving-target is simulated based on material point method to study the effect of the target's transverse movement on penetration effect of the different nosed shapes projectile in this paper.The weak form of the governing equation of the MPM and its discrete form are derived by using the weighted residual method.A method for solving penetration problems is established.The computation code is written and steps of solving problems by MPM are given.Many examples(hypervelocity impact,the projectile penetrating static thin and thick plates)of penetration stationary target have been simulated.The simulation results are compared with the experimental results as well as those by using FEM.It has good agreement with the experiment and FEM results.The results show that simulating penetration problem by material point method be validity and suitability.In order to analyze the influence rule of penetrating damage effect in process of the projectile penetration moving target,the process of different nosed shape projectile penetrating vertical or oblique moving target is simulated,respectively.By the simulation of the projectile vertical penetration,the influence of target's velocity and attack angle on the penetration effect of flat-nosed projectile,spherical-nosed projectile and ogive-nose projectile is analyzed.The penetration damage effect of flat-nosed projectile is compared with ogive-nose projectile as well as spherical-nosed projectile in the same working condition.By the simulation of the projectile obliquepenetration,the influence of projectile initial velocity,the ratio of projectile velocity to target velocity,length-diameter ratio and attack angle on the projectile's residual velocity and the target damage area is analyzed.The rules of ricochet phenomenon of flat-nosed projectile,spherical-nosed projectile and ogive-nose projectile are analyzed.The results show that when the attack angle is zero,the higher the target velocity is,the better the damage effect of the target plate is,and the damage effect of the oval shell is the best.When the attack angle is not zero and constant,the target velocity is larger,the effect of the target plate is worse.The penetration ability of the projectile is the better.Especially when the attack angle is 15 ° or so,the penetration effect is the best.When the attack angle is larger,the velocity loss of oval shells is maximum.The greater the speed ratio of the target is,the weaker the effect of the target movement on the projectile penetration effect is.When the aspect ratio of the projectile is equal to10,the penetration ability of the projectile is best.The larger the dip angle is,the greater the loss of the projectile velocity is and the decrease of the oval velocity is the maximum.The ricochet critical angle increases as the initial velocity of the projectile increases.The ricochet critical angle of oval nosed projectile is least.The research in this paper provides some guiding significance for the design of the moving target and the shape of the projectile nosed shape.