HOLE SIZE FROM IMPACTS AT SIMULATED VELOCITIES TO 23 KM S/

A method is described that allows penetration of thin aluminum plates at velocities up to 23 km/s to be simulated in experiments conducted a t actual velocities below 7 km/s. This is accomplished by replacing th e impactor and plate materials by an appropriate surrogate material th at reproduces, at modest impact velocities, the important physical mec hanisms that occur in a higher-velocity aluminum impact. Dimensional a nalysis is used to identify the similarity conditions that must be sat isfied by the surrogate material. Cadmium is shown to be an excellent surrogate of aluminum that provides a velocity magnification factor of 3.1. Measurements of hole size from aluminum impacts at velocities up to 7 km/s are found to agree well with cadmium tests at the correspon ding reduced velocities. Cadmium results are used to provide estimates of hole size for aluminum impacts at velocities up to 23 km/s.