Research On Random Of Underwater Explosion Problem Based On Material Point Method

The dynamic response of underwater explosion and structure under the action of underwater explosion involves the problems of detonation physics,impact dynamics,large deformation and nonlinear fluid structure coupling multiphase media.The traditional numerical method based on grid algorithm is obviously challenging.This paper is based on a new meshless algorithm--material point method.It inherits the advantages of both Lagrangian method and Euler method,all material information by the material carrying,overcomes the problem of mesh distortion of traditional calculation method,the material interface can be accurately described,these advantages make the material point method in the analysis of explosion shock involving large deformation and attracted a lot of attention,however,there is little research on solving stochastic problems with matter point method,uncertainty exists in practical engineering problems.In this paper,therefore,the stochastic analysis theory is introduced into the material point method,developed a stochastic material point method,considering the parameter randomness of the equation of state for detonation products and the equation of state of water,then illustrate the applicability and effectiveness of the stochastic material point method by compared with Monte-Carlo simulation results.Firstly,the basic theory of the material point method is introduced,such as the space discrete form,the mapping function and the time discrete form of the control equation of the material point method.Then the basic theory of the random variable and the Monte-Carlo simulation is introduced.On this basis,the stochastic material point method and Monte-Carlo simulation are used to simulate the shock wave pressure of underwater explosion of high energy explosives.The mean and variance of explosion shock wave pressure are calculated and compared by choosing different coefficient of variation.The results show that the stochastic material point method and Monte-Carlo simulation result are in good agreement,and the correctness of stochastic material point method is explained.Then the problem of underwater explosion is studied,and the randomness of the parameters of the equation of state of water is considered.considering the parameter randomness of the equation of state of water,the mean and variance of shock wave pressure of water are calculated by stochastic matter point method and Monte-Carlo simulation.Select the different coefficient of variation calculate shock wave pressure mean and variance of water were compared.The results show that the stochastic simulation of material point method and Monte-Carlo calculation results are in good agreement.For the computation time,it showed that the stochastic material point method is much lower than that of Monte-Carlo simulation time,shows the correct and efficient stochastic material point method.