Research On Material Point Method For Gas Explosion Shock Problems

Gas explosions frequently happen in everyday life,industrial production,and military operations.The research of gas explosion impact is of great significance for preventing and reducing explosion disasters in life,industrial production and transportation,and enhancing the power of related military weapons.With the rapid development of computer science and technology and numerical calculation,numerical simulation has become an important way to research gas explosion.Material point method(MPM)is described by both Lagrange particle and Euler grid.MPM avoids the grid distortion problem when the Lagrange grid method is used to calculate the large deformation problem,and solves the problem of the difficult coupling and numerical dissipation when using Euler grid method.In view of the advantages in impact,contact,fluid structure coupling and other problems involving large deformation and material failure,the material point method(MPM)is extended to the numerical simulation of flammable gas explosion after a thorough study MPM.The control equation of material point method is derived in this paper.The linear interpolation function is selected for the mapping function between the particle and the background grid.In order to avoid the problem of numerical noise caused by discontinuous interpolation function,the generalized interpolation material point method(GIMP)is introduced.Based on the material point method and the related knowledge of gas explosion,a calculation program is written to simulate the detonation of combustible gas.The ignition growth model is selected as the detonation model of flammable gas.The ideal gas equation of state is chosen to describe the flammable gas detonation.Artificial volume viscosity is introduced to smooth cross section.The detonation process of acetylene air mixture is calculated by the material point method.The numerical results are in good agreement with the experimental data within 10%,which indicates that the material point method has high feasibility in the calculation of gas detonation.The explosion of acetylene air mixture with different concentrations was calculated by the material point method.The results showed that the maximum explosive pressure of the mixture was the largest when the concentration was 9.7%(about 1.25 times the equivalent chemical concentration).The influence of two kinds of obstacles on the power of gas explosion is compared.The results show that the detonation wave increases greatly when the detonation wave propagates near the obstacle.The constitutive model,state equation and damage model of solid material are established,and The dynamic response analysis of the structure is carried out.When using the material point method,the solid and fluid are in the same solution domain,and the fluid solid coupling algorithm is very simple.So MPM is suitable for solving the fluid solid coupling problem related to gas explosion.The study of material point method is still in its infancy,and there are still many places to be perfected.At present,the numerical analysis software based on the material point method is very rare.It is of great significance to develop the material point method procedure for explosion shock.The material point method is extended to the calculation of gas explosion,and the material point method is further perfected and developed.At the same time,it also provides a new thought for the calculation of gas explosion.