Spall of cylindrical copper by converging sliding detonation

The dynamic tensile fracture of cylindrical OFHC copper subjected to converging waves induced by sliding detonation was experimentally investigated.The inner surface (or free-surface) velocity profiles were measured by the displacement interferometer system for any reflector (DISAR).Analysis to velocity profiles gives some lights on the spalling characteristics of copper. Firstly, if the thickness of the spall scab and the high explosive (HE) thicknesshe are both divided by the wall thickness h of OFHC copper, it follows that the relative thickness /h of the spall scab increases with the relative HE thickness he/h. This accords with the research results of the steel cylindrical shell under the similar loading, however, the critical value of he/h for shell spalling is dependent on its material. Secondly, by comparing with other literatures, it can be seen elementarily that the spall strength of OFHC copper depends weakly on the geometric structure but mainly on the pressure and duration of impact loading. Lastly, the spall strength of OFHC copper is slightly lowered when its thickness increases, where material viscosity and Taylor triangular wave attenuation both contribute, also the dispersion of material.