The Study On Simulation And Protection Of High Speed Water Entry Of Structure

The problem of structural high-speed entry into water is widely existed in ship,aviation,military industry and other aspects.The research on structural entry into water impact is also one of the hot research issues at present.When the movement of body contact surface with high speed movement experience strong transient impact load,impact load of can lead to the serious deformation of structure and even the internal damage caused a certain structure,so the accurate prediction of high-speed water entry about the structure of the shock response and the efficient protection is of great significance for structural designers.This paper adopts the method of numerical simulation study of the impact of high-speed water entry about the structure problem,based on explicit dynamic software provided by the ALE method in ls-dyna,includes structure,water and air of fluid-solid coupling model of three parts,and may affect the accuracy of calculation in the process of solving the related control parameters are discussed analysis,this paper discusses the important keyword file specific meaning of the relevant parameters as well as the method of use.To verify that the software and the use of high-speed water entry about the keyword file in a simulated structure impact question the accuracy of the numerical simulation model is set up,respectively,from the water after the maximum acceleration of moving body,enters the water velocity decay curve,and pressure peak valley three aspects,compared with the related test data collected by validation,the calculated results was coincident with the experimental results,using numerical simulation method can be for subsequent experiment provide important reference value to the design and structure.This paper then briefly discusses the protective structure of the water entry moving body and discusses the excellent performance of the porous metal sandwich structure in the impact resistance problem.Three representative materials were selected from disordered and ordered porous metal materials to be used in the sandwich structure,including metal foam aluminum sandwich structure,regular hexagonal honeycomb sandwich structure and internal hexagonal negative poisson's ratio honeycomb sandwich structure.The feasibility of in-plane equivalent method in dealing with large deformation of structure is analyzed by means of numerical simulation.Finally,also using the ALE method in ls-dyna,respectively,set up the finite element model of high-speed water entry about the three kinds of sandwich structure,with quality,speed under normal structure into the water,such as comparative analysis of the bearing state,after finally verified the porous metal sandwich structure in the water under the action of impact load of shock resistance,it can be used in high speed into the protective structure of water movement.