Experimental And Simulation Study On The Process That Deflagration Boosting Projectile Penetrates Into Concrete Targets

The deflagration boosting projectile, which is composed of multi-stage deflagration boosting mechanisms, is a new concept Earth Penetrating Weapon. Owing to the multi-stage deflagration boosting, it can obtain much deeper penetration depth. Through experimental methods and numerical simulations, the process that deflagration boosting projectile penetrates into concrete targets is across-the-board researched in this dissertation, and the research results can afford some important reference and theoretical basis for the manufacturing of deflagration boosting projectile. The followings are the main contents of this dissertation:1) The movement and damage situations of the fracture-zone concrete are researched. In the research, the subscale test is designed and multilayer colorized concrete target is made. After been penetrated by the kinetic energy projectile, the target is cut. Because the concrete in different part has different color, the displacement of the concrete in the region which is the part surrounding the bullet-hole and is more than triple projectile diameter is easily found. Basing on dry and wet dividing line on the concrete cut surface, the damage of the fracture zone is obtained. The experiment is simulated with LS-DYNA3D, and the numerical analysis tallies closely the experiment. Then the simulation study method is used in the penetrating study of the real projectile, and the movement and damage situations of the fracture-zone concrete are obtained. It affords some important references for design of the deflagration boosting mechanism.2) The keyhole delayed ignition technology in deflagration boosting mechanism is researched, and its interior ballistics model is established. The interior ballistic experiment of double-chamber fire mechanism is done, and the changing situations of pressure in two chambers are measured in the experiment. Then the working process of the keyhole delayed ignition device and the change laws of pressure in each chamber are discussed. After that, the interior ballistics model is established and the calculation is done. Comparing the pressure-time curve which is obtained by the theoretic calculation with the curve which is measured in the experiment, it shows that the model is correct. So the interior ballistics model of the deflagration boosting mechanism is established by this method.3) The semi-empirical calculation formula of penetration resistance which can be used for deflagration boosting projectile penetrating into concrete targets is researched, and its engineering calculation model is established. Li and Chen deduce the Forrestal resistance modified model, but the acceleration term affecting the resistance is ignored in their researches. Basing on the cavity-expansion theory and considering the influences of projectile acceleration on penetration resistance in the penetrating process, it solves the acceleration term and deduces the semi-empirical calculation formula of penetration resistance. Then combining the study of the interior ballistics model, the engineering calculation model of the penetrating process is established.4) The numerical simulation model of the Process that deflagration boosting projectile penetrating into concrete targets is established. The process is simulated with LS-DYNA3D. The model which is built in finite element simulation is reasonable and the material model which is chosen is suitable. Then combining the research of this dissertation, the interior ballistics model is used to simulate the deflagration boosting process, and the technique of data exchange in simulation is determined. After that, the penetrating process is simulated.5) The kinetic energy and deflagration boosting penetrating into concrete targets experiments of the three-level deflagration boosting projectile are done. The kinetic energy penetrating experiment not only verifies that the projectile structure and the main components can endure the overload in the kinetic energy penetrating, but also provides the test data for the parameter selection in the theoretical research. The deflagration boosting penetrating experiment shows that the penetration depth increases by nearly20%through the deflagration boosting, the design scheme is rational, and the model is proper.6) The research of influence factor in the deflagration boosting projectile’s penetration depth is done. Through the calculation, the influences of technical points on penetration depth are researched. The technical points include the ignition timing of fuse, the keyhole delayed ignition, the mass distribution of the projectile, the charge weight of each deflagration boosting mechanism distribution, the species of gunpowder, and so on. Also the design principles of technical points are obtained. Then improved design scheme of the three-level deflagration boosting projectile is put forward.