Simulation Investigation On Penetration Based On Element Free Galerkin Method

Armor piercing research has been an active field on impact dynamics and military science and technology. As kinetic energy projectile would be an important direction of anti-tank weapons in the future, needed to be studied deeply, and the numerical simulation has been used popularly in armor piercing research in resent years because of the advantages of its economy and repeated observations. A numerical simulation investigation was studied based on Element Free Galerkin method in penetration in this paper. The main courses were summarized as follows:Firstly, the developments of the method in penetration and the application to Element Free Galerkin (EFG) method in the field of engineering were summarized in this article. On the basis of the advantages and disadvantages in EFG, the proposal was proposed to deal with the negative volume phenomenon, which was usually occurred in numerical simulation process in finite element method.Secondly, according to the moving least-square method, the relationship between stress and strain under the condition of elastioplastic, the equations of projectile motion were derived. And then, the numerical discrete equations of EFG method were shown in the condition of the elastioplastic behavior and deformation of the thin plates. After that, the calculation steps were illustrated with the necessary boundary conditions and integration scheme.Thirdly, the computational model was established by the physical model with necessary assumptions and simplification, geometry model and material model with Johnson-Cook equation and Gruneisen state equation. The simulation analysis was finished by rigid spherical projectile penetrating double-infinite steel targets in three-dimensional. The simulation results, especially the velocity and acceleration of the rigid projectile, were compared with cavity expansion theory and finite element method (FEM) in the same conditions, confirmed that the EFG method was feasibility and superiority, but low efficiency in the simulation.At last, because of a large number of computations and relatively lower efficiency to finite element method, a method, called element free Galerkin-finite element method (EFG-FEM) based on coupling shape function, was proposed. The numerical simulation analysis was completed again with the coupling algorithm in the same conditions. And the coupling algorithm in penetration was proved its not only high efficiency but also correct by comparing the results with finite element method, the exiting experimental pictures, empirical formula and so on. After that, the factors that affect the result in numerical simulation were researched by calculating and comparing, such as the different nodal distribution, area size in the zone with the EFG method and the thickness of thin plate.In a word, the EFG method was used to deal with the negative volume phenomenon in penetration in numerical simulation. In order to improve efficiency, the element free Galerkin-finite element method was adopted. However, the coupling algorithm was not perfect, needed further improvement.