Numerical Analysis On Bebonding Of TATB Based Polymer Bonded Explosive Caused By Heating And Cooling Process

Polymer bonded explosive(PBX)is a kind of heterogeneous compound material composed of energetic crystals and binder,which has microstructure.Under the influence of thermal environment,the interface between energetic particles and binder will be debonded,which would affect the macroscopic mechanical properties,safety performance and detonation performance of PBX.In order to explore the relationship between temperature changing and interfacial damage,five PBX two-dimensional geometric models with different volume fraction of energetic particles were generated based on Voronoi theory and Monte Carlo grading idea and three PBX two-dimensional geometric models with similar volume fraction and different particle sizes and arrangement of energetic particles were established.In the selection of constitutive model of PBX,the influence of temperature change on the thermodynamic properties of energetic particles and binder was considered and the bilinear cohesive force constitutive model was introduced to describe the mechanical properties of energetic particles-binder interface.The phenomenon and mechanism of PBX damage on the interface during the heating and cooling process were studied and discussed by means of numerical analysis.The results of numerical analysis showed that the interfacial debonding behavior around energetic particles was more likely to be dominated by shear stress when the temperature increased and the interfacial debonding behavior around energetic particles with larger particle size is more likely to be dominated by tensile stress when the temperature decreased.Compared with the heating stage,PBX explosive with the same geometric model was more likely to generate interfacial debonding when it was cooled down,which was consistent with the experimental results.The results showed that the increase of PBX particle volume fraction was helpful to reduce the interfacial debonding while the closer the particle volume fraction was,the more uniform the particle sizes were.The smaller the interfacial damage generated,and the smaller the particle size is.When the particle sizes were very different from that of the surrounding particles,the interface around the larger particles was more likely to be damaged during cooling process.