Application of acoustoelasticity in studying compressive stress state in Polymer bonded explosive

The acoustoelastic technique is a nondestructive technique for analyzing the stress state in materials using ultrasonic waves. The velocities of the ultrasonic waves propagating through Polymer bonded explosive (PBX) change depending on the applied stress (compression or tension). In this paper, PBX specimens at close range of densities and ultrasonic wave velocities under similar initial conditions are applied in the compressive loading tests. Ultrasonic longitudinal wave propagation direction is parallel and perpendicular to applied stress direction respectively. Longitudinal wave velocities are accurately and efficiently achieved by real-time Ultrasonic time differences (velocity) measurement unit. In the range of stress evaluated under compression between 0 and 15MPa, these relations between the relative variation of the longitudinal wave velocity and the applied stress vary linearly. The value of acoustoelastic constant (K) can be determined by the compression tests. These founds suggest the potential of applying the acoustoelastic effect to determine the compressive stress condition of PBX in a certain stress range.