Measurement and Modification of Dynamic Friction Coefficient of Pressed Explosive

In order to investigate the effect of dynamic friction coefficient on the friction ignition of pressed explosive, 8701 pressed explosive is tested on the friction testing system based on the drop hammer apparatus, and tthe coefficients of dynamic friction between 8701 pressed explosive and 45^# steel at different normal pressures are studied. The experimental results show that, when the normal pressure is increased from 1 MPa to 10 MPa, the dynamic friction coefficient is reduced from 0.28 to 0.10, indicating that the dynamic friction coefficient is dependent on pressure. A calculation model of the friction coefficient is proposed based on the experimental results and introduced into the LS-DYNA through secondary development. The thermo-chemo-mechanical coupling numerical simulation is conducted for the skid test of 8701 pressed explosive. The calculated results show that the improved calculation model of friction coefficient prolongs the ignition delay time, increases the critical ignition velocity and raises the critical ignition temperature. The proposed model can be used to study the non-shock friction ignition problem.