The Explosively Formed Penetrator And Its Engineering Damage Effects Research

EFP(Explosively Formed Projectiles) is an useful weapon and has bright future in the development of end sensitive bullet and second series bullet as well as in the field of clearing away the engineering barriers and destruction of weapons. To develop good EFP, therefore, is always a popular topic in the weapon design and explosion mechanics. According to the demands of clearing away the engineering barriers and attacking the firm military objectives, The dissertation aims at the objective to develop an efficient EFP ammunition with small weight, low cost and easy to use and to carry. Both the exterior ballistic trajectory and the cost of EFP are considered and stressed, and in the meantime the importance to increase the penetration capability of EFP is taken into consideration. Three steps are adopted in the developments of EFP, i.e. the primary design on the basis of theory and experience, the feedback design related to the numerical simulation, and finally the optimizing design based on the experiments. Finally, the available EFP ammunition is obtained and its efficiency in the penetration and performation are studied. A convenient engineering method to estimate the penetration depth is proposed and some effective protective measure are suggested.Firstly, we described and summarized systematically the research fruits in the shaped charge technology both at home and abroad, such as the research history and classification of EFP, the criterion to form congregated jet and its related theory, the research method of shaped charge, the advantages and its applications of EFP, the main factors and its function in the formation of EFP, and so on. Considering the outstanding performance of EFP in attacking composite armors, the strong pentration capability in the concrete and insensitive to the detonation hight, a clear aim of the dissertation is determined.Then, the method to design EFP warfare is studied thoroughly and the deformation characteristics of charge liner in the formation of jet is investigated. It is concluded that the primary condition to determine EFP mode is the velocity distribution along the charge liner. Based on the driven model of flyer flat, formulas for the velocity and deformation of charge liner are derived and a tentative warefare of EFP is designed. LS-DYNA is used to simulate the formation of congregated jet and the penetration of formed projectiles. The key point in the simulation is that the whole calculation is subdivided into two steps, i.e. the first to simulate the explosively formed projectile and the second to simulate the penetration of the projectile into target. In the numerical simulation several effective measures are used, such as, hourglass deformation is controled by anti-hourglass nodal force, penalty function is used in the simulation of slidding surface, adaptive method is adopted for severe distortion meshes, and so that the whole simulations go through smoothly. After a series tests and analysis of the shape and flying posture of EFP, an ideal composite charge liner consisted of a part of sphere liner with variable thickness and a big angle cone liner is developed, which meets the demands of shape and penetration performance of EFP. Combining the numerical computations and bullet tests,...