The mechanical response of a PBX and binder: combining results across the strain-rate and frequency domains

D R Drodge (1) , D M Williamson (1) , S J P Palmer (1) , W G Proud (2) , R K Govier (3)

1 CAM - University of Cambridge [UK]
2 Institute of Shock Physics
3 AWE Aldermaston

The mechanical response of a polymer bonded explosive has been measured using a Split Hopkinson Pressure Bar at a strain-rate of 2000 s -1, across a range of temperatures from 173 to 333 K, with the aim of observing its behaviour in the glassy regime. The yield stresses increased monotonically with decreasing temperature and no plateau was found. The failure mechanism was found to transition from shear-banding with crystal debonding fracture to brittle failure with some evidence of crystal fracture. Similar experiments were performed on samples of its nitrocellulose-based binder material, at a strain-rate of 3000 s -1 across a temperature range of 173-273 K. The failure stresses of the binder approach that of the composite at temperatures near -70°C. The elastic moduli were estimated from post-equilibrium regions of the stress-strain curves, and compared to those obtained for the composite using 5 MHz ultrasonic soundspeed measurement, and powder DMA measurements and quasi-static behaviour reported in a previous paper. The moduli were plotted on a common frequency axis: a temperature-shift was applied to collapse the curves, which agreed with the Cox Merz rule.

Mots clés: Physical Sciences

D R Drodge, D M Williamson, S J P Palmer, W G Proud, R K Govier. The mechanical response of a PBX and binder: combining results across the strain-rate and frequency domains. Journal of Physics D: Applied Physics, 2010, 43 (33), pp.335403. ⟨10.1088/0022-3727/43/33/335403⟩. ⟨hal-00569681⟩