Mechanism Research Of Combustion Reaction Of Multi-component Explosives At Mesoscale Based On Material Point Method

With the development of modern military,aerospace and other national defense fields,it is of great significance for national defense security and industrial development to carry out research on energetic materials,and also has higher requirements for the study of combustion performance of energetic materials in storage,service or working stage.Because the transient dynamics problems,e.g.combustion process,of energetic materials are very complex,it is difficult to carry out theoretical analysis and experimental research.With the development of computer,the research of simulation-based engineering science in transient dynamics has received more and more scholars' attention,but the research on the combustion stage of energetic materials under mesoscopic scale is still at the exploratory stage.It is of great significance for theoretical research and engineering application of energetic materials in military fields to carry out research on the combustion mechanism of energetic materials such as explosives and to establish a numerical method for analyzing the combustion response mechanism of energetic materials under the mesoscopic scale.Based on the basic theory of the meshless method--Material Point Method(MPM),this paper studies the combustion response structure of multi-component explosives under the mesoscopic scale,and the specific research content includes the following aspects:(1)The calculation program for explosion and shock dynamical problems based on the theory of MPM is given,the algorithm theory and the programming program are verified by using specific numerical calculations,and the calculation efficiency of the material point method on solving specific problems such as axis symmetry and large deformation is discussed and studied.(2)Numerical studies are carried out on the properties of multi-component explosives under the mesoscopic scale,geometric models of multi-component explosives are established,the constitutive model,named as “Viscoelastic-Statistical Crack Mechanics”,of explosive damage are studied,stress renewal algorithm and pressure wave propagation mechanism of multi-component explosives under the mesoscopic scale are given.(3)The combustion characteristics and combustion laws of energetic crystal particles under mesoscopic scale are studied,the thermodynamic properties of the combustion process of energetic crystal particles are analyzed,and the chemical reaction thermal and mechanical coupling analysis algorithm are given,the combustion mechanism of energetic crystal particles under mesoscopic scale is analyzed.(4)The equation of state of multi-component explosives under mesoscopic scale are given,the numerical algorithm of multi-material MPM in the combustion process of multi-component explosives is proposed,the formation of "hot spots" of multi-component explosives under mesoscopic scale is analyzed by using heat balance equation,and the numerical algorithm of combustion process of multi-component explosives under mesoscopic scale based on material point method is established,and the correctness of the algorithm and program is verified.(5)A new mathematical model of deflagration to detonation transition of energetic materials is proposed,the basic assumptions and conservation equations of this model are given,the equation of state of the deflagration to detonation transition phase of energetic materials are established,the discriminant conditions for the deflagration to detonation transition are given,and the correctness of this new method is verified by specific numerical calculations.