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

This paper provides a description of a simple and cost-effective continuous measurement system for impact. Originally developed at Johns Hopkins unive rsity for use in flyer plate impact experiments, the measurement system has been enhanced for the continuous, non-contact measurement of projectile di splacement during ballistic impact events. A sheet of laser light is progre ssively blocked and unblocked by the projectile, and the corresponding chan ge in total intensity is measured and converted to a displacement-time curv e. Through the use of simple mathematical operations, the system can be use d 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 pap er presents examples of measurement results for impact of composite and tex tile targets. (C) 2000 Elsevier Science Ltd. All rights reserved.