Dynamic response of thin triangular plates under gaseous detonation loading

During a high-velocity plate forming process accompanied by dynamic loading, a large deformation is generated in a very short time. Gaseous detonation in an obstructed channel is a good way of producing interior shock waves. Pressure waves with high strength have interacted with a plate as a fundamental mechanism of the whole forming process. This study investigates the response of thin steel plates with three different thicknesses clamped on two different triangular frames under various pre-detonation pressures of acetylene-oxygen mixture experimentally and analytically to determine the permanent deformation profiles of plates. Deflection profiles showed large plastic deformations with the maximum deformation happening at the center of mass of the triangular plate. By adopting an energy method approach developed earlier for circular plates, and incorporating a newly developed condition, upper bounds are obtained for the center of mass deformation of the triangular plate. Besides, the influences of some important parameters including plate thickness, steel yield strength, and triangular clamp sizes on the displacement of the plate were evaluated. The results from analytical studies demonstrated a good agreement compared with experiments and showed that the center of mass displacement decreases greatly involving thicker plates and strain rate. It is indicated that the uniform deflection of the plate induced by the interaction of shock waves and the structure can be promoted by gaseous detonation in a confined truncated conical space. Energy method as a useful tool in the evaluation of the hindrance caused by the limited geometry of the triangular clamp on deformation illustrated that midpoint deflection was suppressed by the smaller size of the exposed area of the plate.