Study On Dynamic Mechanical Properties And Ignition Behavior Of PBX

Recently,ammunitions safety is a hot research issue.Under low speed impact,explosives could ignite accidentally or even explode.In this paper,the dynamic mechanical properties,damage evolution and ignition behavior of a typical press-mounted PBX explosive were studied by combining experiment,theory and numerical simulation.It mainly includes the following aspects:Firstly,the uni-axial compression and passive confining pressure experiments of PBX-1explosive were designed based on Hopkinson bar,and the mechanical properties of PBX-1explosive under different loading conditions and strain rates were obtained.The compressive stress-strain curves of PBX explosive under quasi-static loading conditions were obtained by using a quasi-static testing machine.The damage morphology of the recovered samples was observed by SEM,the damage mechanism of PBX explosive was revealed,and the internal relationship between micro-crack evolution and macroscopic mechanical response under different stress states was studied.Secondly,the micro-crack damage evolution equation was established based on generalized energy release rate and dynamic fracture theory.The stress and strain relationship of material bulk element was deduced by coupling micro-crack bulk element and generalized viscoelastic bulk element in series,and the visco-elastic statistical micro-crack damage constitutive relationship of PBX-1 explosive was established.The VUAMT subroutine was compiled with Fortran language and substituted into ABAQUS to simulate the dynamic compression and passive confining pressure of PBX-1 explosive,which verified the correctness of the model.Finally,the PBX-1 explosive multi-axis impact test device was designed based on the light gas gun device,and the load history curves under different bullet velocities were recorded to obtain the critical ignition velocity of PBX-1 explosive.The numerical simulation was carried out by using the damage model,which further verified the correctness of the damage model under multi-axis loads.The difference method was used to solve the micro-crack friction hot spot model,and the PBX-1 ignition process was numerically solved and analyzed.The ignition temperature history curve of PBX explosive under low speed impact was obtained.