Particle Generation Method For SPH And The Application Of SPH To Penetration Of Metal Targets By Projectiles

Metal materials are widely used in military vehicles,such as protective armor.As this kind of protection structure is often threatened by bullets,explosive fragments and so on,it is very important for the design of this structure to study the protective performance of metal target plate under the penetration of projectiles.The penetration of projectile into target plate is a large deformation problem of high temperature,high pressure and high strain rate.Numerical simulation is an economical and efficient approach to the study of the problem.Smoothed particle hydrodynamics(SPH),as a meshless Lagrange particle method,has advantages over other conventional numerical methods in dealing with such problems.However,the calculation of SPH requires regular and uniform particles to ensure the accuracy and stability of the calculation.However,for complex structures,it is difficult to generate.Therefore,this paper carried out the research on particle generating method of SPH and application development of the generation of projectile penetrating steel target Weldox 460 E target.The SPH method was used to carry out numerical simulation with parametric analysis,systematic study of the influence of projectile target structure on projectile penetrating steel target of Weldox 460 E.Specifically,the following work is accomplished:(1)Study of particle generation method.A new particle generation method for SPH was proposed,and it was achieved based on the secondary development of ABAQUS.Several typical particle generation examples were given.The superiority of the present method was verified through a comparison of particle distributions obtained by different methods.A twodimensional automatic SPH particle generation software was developed based on the present particle generation method.(2)Study of influence of projectile structure on the perforation process of Weldox 460 E target.Particle models for the perforation of Weldox 460 E targets by projectiles with different nose shapes and aspect ratios were efficiently generated with the proposed particle generation method.SPH models were established for the problem and solved with an axisymmetric SPH method.The effectiveness of simulation results was validated by existing experimental data.Then,parametric numerical simulations were carried out.The effects of nose shape and aspect ratio on residual velocity of projectile and failure mode and ballistic limit velocity of target were analyzed.In addition,an analytical method was used to calculate ballistic limit velocities of targets perforated by projectiles with different structures.The obtained results were compared with SPH simulation results.(3)Study of influence of target structure on the perforation process of Weldox 460 E target.SPH models for blunt and conical projectiles penetrating into monolithic targets with different thickness and layered targets with different layering schemes were established.The axisymmetric SPH method was used to solve the models.Based on the SPH simulation results,an empirical formula was established for ballistic limit velocity of monolithic target.Also,effects of number of layers,total thickness,thickness configuration and spacing between layers on the ballistic performance of layered targets were revealed.In addition,an analytical method was used to calculate the ballistic limit velocities of layered targets.The obtained results were compared with SPH simulation results.(4)Study of Weldox 460 E steel target under repeated penetration of multiple projectiles.SPH models for Weldox 460 E steel target subjected to repeated penetration of multiple projectiles was established.The ballistic limit velocity of the target was obtained.The critical energy required for the perforation of the target was calculated and compared with that for a single projectile.The particle generation method developed in this paper can improve the pre-processing efficiency and modeling accuracy for SPH,consequently facilitate its application.The results for effects of projectile and target structure on ballistic resistance of Weldox 460 E steel target can provide reference and guidance for the design of protective structures with the studied material or similar materials.