Linear elastic response of tubes to internal detonation loading

Abstract

This paper deals with the structural response of a tube to an internal gaseous detonation. An internal detonation produces a pressure load that propagates down the tube. Because the speed of the gaseous detonation can be comparable to the flexural wave group speed, excitation of flexural waves in the tube wall must be considered. Flexural waves can result in much higher strains and stresses than static loading with the same loading pressures. Experiments and numerical simulations were used to determine the structural response. In the experiments, a detonation tube was instrumented with a number of strain gages. A series of experiments was carried out under different conditions. Strains were measured that exceeded the equivalent static strain by up to a factor of 3·9. Special attention was paid to the influence of the detonation speed, reflection and interference of structural waves at flanges and also at the tube end, the linearity of the response, the transient development of the deflection profile, and the influence of detonation cell size. Analytical models and finite element models were used to interpret the observations and to make quantitative predictions of the peak strain.