Statistical analysis of NRL 1964–1969 hypervelocity rod-plate impact data and comparison to recent data

The previously reported Naval Research Laboratory hypervelocity rod-plate impact database was studied to derive the statistical variation that could be assigned to measurements of rod erosion for various impact conditions and impacting materials. The database covers impacts of 3.175 mm diameter rods having diameter-to-length ratios of 10 at velocities between 2.6 and 6.1 km/s upon targets whose thickness varied from 0.0355 to 6.5 rod diameters. Seven different projectile materials and 10 different target materials as well as alloys of aluminum and steel were tested. Of the 275 individual impacts reported, 157 were selected for statistical analysis. It was found that all of the data were normally distributed with a mean of 0.966 and standard deviation of 7.6% of the mean when the individual experimental measurements of rod erosion were normalized to predicted values calculated for the same impact conditions using the semi-empirical equation reported by Baker. Using this normalization, recent data from a multiple plate impact experiment was found to lie well within the uncertainty band. Subsets of the data are discussed.