基于自适应 FEM-SPH 耦合算法的飞机典型部位破片冲击战伤的数值研究

A numerical simulation study is carried out on the overall battle damage circumstances of structures and the residual behavior of fragments after the typical parts of aircraft are attacked by high-velocity fragments. An adaptive FEM-SPH coupling simulation method is established by using the LS-DYNA software and combining the advantages of finite element method (FEM) and smoothed particle hydrodynamics (SPH). Using this coupling simulation method, the computational model of two typical parts of the aircraft is set up, and the accurate simulation of the core position is realized by a local refinement method of hexahedral FEM grids. Experiments were carried out to verify the numerical model. A series of high-velocity impact (HVI) battle damage simulations are carried out. The debris cloud and crater appearance formed after fragment impacting on structure at high velocity under different working conditions are compared, while the residual velocity and mass of the fragment are analyzed. The critical ricochet angles of the fragment on the skin are also determined. The major conclusions are given below. The calculation results of the adaptive FEM-SPH coupling algorithm are in good agreement with the experimental results, and it can simulate fragment HVI damage effectively and precisely. The distribution shape of debris cloud becomes narrow and long with the increase of fragment incident velocity, and the incidence angle can change the shape orientation of debris cloud and crater on the structure. The variation trends of height and spread velocity of debris cloud with incident velocity or angle are basically consistent and linear. The velocity reduction of the fragment does not change with the incident velocity, and the mass reduction is positively correlated with it, both of which are negatively correlated with the incidence angle. The critical ricochet angle of fragment varies almost linearly with the incident velocity. The research results can provide a reference for the damage prediction and rapid maintenance of aircraft after air combat.