IMPACT FLASH EVALUATION OF STEEL AND ALUMINUM PLATES AT VARYING ANGLES WITH MILLIMETER SIZED IMPACTORS

Significant work has been done on characterizing the flash from hypervelocity impacts for space and defense applications. However, singular small impactor events on the 1 mm scale are difficult to perform and characterize due to challenges in launching them and setting up diagnostics that can capture the small flash. Spurred by interest and funding from Johns Hopkins University Applied Physics Laboratory to look at impact flash with small projectiles on different materials at two angles of impact (45 and 90 degrees), the HyFIRE lab at JHU ran trial experiments to launch 1 mm spheres form a 30-caliber barrel at aluminum and steel plates. Steel sphere launches were performed, and the impact flash was viewed using high speed video from a side perspective as well as broadband photodetectors and a spectrograph from 2 viewing angles. Experiments were done at 45 and 90 degrees impact angles. Variation in the viewing angle and flash magnitudes were seen as well as variation in the material spectra. Tunable spectral equipment was useful in capturing the differences between materials, and future work will be done for magnitude calibration to help with temperature calculations.