Research On Damage Effect Of Oval Projectile Penetrating Multi-layer Targets

At present,the damage effect of a ship usually comes from the implosion stage of a semi-armor-piercing projectile,and less attention is paid to the penetration of a ship's target plate in the previous stage.However,in the penetration stage,the impact of the target plate,especially the multi-layered/stiffened target plates,on the attitude and trajectory of the projectile body will eventually affect the penetration ability of the projectile body.The main research contents are as follows:1?From the theoretical point of view,the one-dimensional shockwave theory of the projectile penetrating the metal target plate is summarized to calculate the impact pressure,and the interface pressure is obtained according to the interface continuity condition through the mass and momentum conservation of the shockwave.The stress state of the impact point is represented by polar coordinates,and the damage of the target plate caused by the coupling of normal stress and shear stress is obtained.The damage of the target plate is elliptical.2?The numerical simulation model was established by ANSYS/LS-DYNA finite element software.The calculation results obtained under the same calculation conditions as the experiment,such as residual velocity,break shape and overload,are checked to ensure the validity of the model parameters.The minimum grid size is determined by using reasonable numerical parameters.3?In this paper,ANSYS/LS-DYNA is used to simulate the damage of the projectile body penetrating the target plate of multi-layer ships.The stress,strain,residual velocity and overload of the target plate were obtained by LS-PREPOST post-processing software.The formation process of the target plate fracture is analyzed,and two main factors of the target plate fracture in the same target system are obtained by dimensional analysis: Angle of impact and Angle of attack.In order to simplify the problem,the penetration mode was divided into angular penetration mode and Angle of attack penetration mode,and the deflection Angle variation,angular velocity and ballistic direction of the projectile body through the target plate under different penetration modes were obtained through a large number of working conditions,so as to determine the Angle of attack and Angle of impact of the projectile body through geometric relations.Through fitting,the formula for calculating the size of the target plate under the penetration mode including Angle of attack,Angle of impact and velocity is obtained,and the size of the target plate can be predicted.4?The penetration process of the stiffened target plate is simulated,and the stiffened target plate is equivalent to the mean target plate by mass equivalence.The velocity change and energy loss distribution of the projectile body to the two different structural target plates,the projectile body attitude and trajectory change,and the target plate rupture and damage are compared and analyzed.