Dynamic response of cylindrical shells to impulsive loading

Abstract

A program was undertaken to investigate the dynamic response of cylindrical shell panels to impulsive loads. Hot--rolled mild steel and aluminum 6061-T6 panels of various thicknesses and two panel sector sizes were loaded internally with DuPont "Detasheet" explosive. Calibration tests were conducted to determine the specific impulse of the explosive. The explosive impulse was sufficiently high to result in permanent plastic deformation of the shell panels. The final permanent deflections of the panel specimens were measured. Plots were made of the center deflection of the specimen as a function of the initial velocity and of the center deflection as a function of a nondimensional impulse parameter. Comparison of the results of tests on specimens made from mild steel, a strain-rate sensitive material, to those of aluminum 6061-T6, which is insensitive to strain-rate, revealed that the permanent deflections of the mild steel specimens were reduced. Thus it is concluded that the effect of material strain-rate sensitivity is important and must be considered in analyzing the response of cylindrical shells to impulsive loads. It is also concluded that the influence of geometry changes is insignificant on the cylindrical shell deflections in these tests. Although, to the author's knowledge, there are no present theoretical methods of analysis with which these results may be compared, rigid-plastic methods of analysis are bring developed at the Massachusetts Institute of Technology. It is hoped that the results reported here will aid in assessing these methods of analysis.