The Dynamic Simulation Upon Impact Of Torpedo And Target In Different Medium

Modern torpedos can attack underwater target by a variety of launch methods,but in either case,torpedo must navigate in the water before hit the target.At the moment of hitting the target,a relatively larger impact load will be generated,which will bring a great negative influence on the shell and the internal acceleration detection device of the torpedo.In serious case,the corresponding parts will be destroyed,and the detonation signal can not be output,leading the torpedo can not be detonated after hitting the target.Therefore,it is of great significance to improve the reliability of the torpedo system by studying the influencing factors of the impact load and the acceleration response of the detection device.In response to the dynamics of the impact between torpedoe and target.Firstly,this paper reviews the research progress of torpedoe,torpedo water-entry and impact at home and abroad.Secondly,the spring-mass mechanics model is used to study the impact vibration problem,and the effects of initial velocity,mass and material stiffness on the impact load are compared and discussed.At the same time,the centroid acceleration of the rod is abtained according to the wave equation of the one-dimensional elastic rod,and compared with the rigid rod,the effect of the stress wave on acceleration is relatively larger,then the acceleration response is analyzed by changing the pulse load.Finally,from the perspective of the finite element theory of dynamic analysis software LS-DYNA,this paper mainly introduced the theory of explicit algorithm,contact collision and fluid-solid coupling.The above contents provide powerful support for the later impact simulation analysis of the torpedo and target in multi-media.Based on the above research contents.LS-DYNA is used to simulate the impact of torpedo and target in the air.The details are as follows: 1.The effect of torpedo's head material on the impact results are compared and discussed.When the aluminum alloy is selected,the impact load is higher than that of the rubber material,and the impact load increased with hardness of the rubber material.2.The effect of initial velocity,angle and torpedo quality on the impact load and the acceleration response of detection device are quantitatively analyzed.3.The situation of stress wave delay is discussed when the torpedo impact with target,and then checked by the theory of wave velocity.In order to obtain more realistic results,the fluid-solid coupling simulation technology is used to simulate the impact of torpedo and targets in water.The details are as follows: 1.A water model is built around the torpedo and target,and the far-field boundary conditions are set at the periphery of the water field to simulate the torpedo in the infinite water environment.Then the whole model is treated with the hydrostatic pressure balance to realize a water pressure environment.2.A variety of simulation methods of impact in the water are discussed,such as the additional mass method,the fluid-solid coupling method and the fluid-solid coupling with water pressure.The results show that the impact load is larger when the water pressure is considered.3.Different depths of water are selected to observe the change of impact load,which shows that the impact load increased with the water depth.4.The result of the impact,whose collision conditions are the same as in the air,is compared with the result in the air.