An efficient method for continuous measurement of projectile motion in ballistic impact experiments

Abstract

This paper provides a description of a simple and cost-effective continuous measurement system for impact. Originally developed at Johns Hopkins university for use in flyer plate impact experiments, the measurement system has been enhanced for the continuous, non-contact measurement of projectile displacement during ballistic impact events. A sheet of laser light is progressively blocked and unblocked by the projectile, and the corresponding change in total intensity is measured and converted to a displacement–time curve. Through the use of simple mathematical operations, the system can be used to determine the time histories of projectile velocity and acceleration, impact force and projectile energy loss during an impact event. While this technique can be applied to a wide range of engineering materials, this paper presents examples of measurement results for impact of composite and textile targets.