Measurement and analysis of stress waves in concrete target under hypervelocity impact

To investigate the stress wave characteristics within concrete targets under hypervelocity impact, a stress wave testing system based on polyvinylidene difluoride (PVDF) piezoelectric stress gauges was established. A calibration method for PVDF piezoelectric stress gauges was proposed and conducted. The stress waveforms within concrete targets impacted by kilogram-scale cylindrical 93W tungsten alloy projectiles at hypervelocity were measured, and the generation and propagation mechanisms of stress waves were analyzed using numerical simulation methods. The following conclusions were drawn: (1) the dynamic characteristic parameters of the PVDF piezoelectric stress gauge were calibrated to yield a dynamic sensitivity coefficient of (17.5±0.5) pC/N for the PVDF piezoelectric stress gauge; (2) high signal-to-noise ratio stress waveforms within the concrete target under hypervelocity impact conditions were obtained using the PVDF piezoelectric stress gauge; (3) the stress waveforms obtained from numerical simulation were in good agreement with the experimentally measured waveforms where the maximum deviation of the stress wave peak values between simulation and experimental results is less than 20%, providing a useful tool for mechanism exploration; (4) the characteristics of stress waves within the concrete target and the mechanisms of generation and attenuation were further explored using numerical simulation methods.