Mechanical properties characterization of Polymer bonded explosives based on Dynamic elastic modulus measurement

In this paper, for nondestructive and quick investigation of the dynamic elastic modulus of PBX, a measurement system based on ultrasound velocity technique has been presented. The accuracy and reliability of the dynamic elastic modulus calculated by the velocity of ultrasonic longitudinal and transverse wave, which synchronizing received and transmitted by a new integrated sensor have been studied. Thermal cycling tests of different formulations of PBX, HMX and TATB based PBX, are undertaken at the scope from -54～74℃. Dynamic elastic modulus is measured by the nondestructive measurement system to compare with static elastic modulus. The results show that dynamic elastic modulus, dynamic/static elastic modulus ratio reflect the difference of mechanical properties and material consistency. Dynamic elastic modulus quickly decreases to a low value and vibrates as the thermal cycling being in progress and mechanical properties decrease to a lower degree. After resting for a month, dynamic elastic modulus recovers in some degree along with mechanical properties. At preliminary stage of the thermal cycling, dynamic/static elastic modulus ratio increases and material consistency decreases, with micro-defects’ initiation, as cracks and voids et. Along with the increase of the thermal cycling, dynamic/static elastic modulus ratio decreases on the contrary. PBX recovers consistency, with micro-defects’ self-healing, in a lower level of mechanical properties.