Continuous measurement of the projectile velocity during ballistic impact in flexible body armour

In the experimental research on the response of ballistic fabric on impact the measurement of the projectile velocity is generally limited to a discrete measurement of impact and residual velocity. In this paper a technique for the continuous measurement of the projectile velocity during the penetration is presented. This is important for the validation of numerical simulations and development of analytical models. The technique is based on the Doppler effect and involves the use of a continuous wave radar. This technique is combined with high-speed video images to obtain a detailed description of the penetration process. Results show that the velocity doesn't decrease immediately after impact. This is probably due to the way the fabric is fixed in the frame and indicates that a standardised fixation method for fabric behaviour testing is needed.