Multiple Fracture of Plates Under Localized Impulsive Loading

An investigation was performed to determine the fracture patterns produced by localized impulsive loading on brittle plates and their dependence on the intensity and area of the load. Experiments were performed on effectively infinite plates loaded over a finite area with sheet explosive. The mechanisms, location, and time sequence of deformation and fracture were determined by terminal observation, high-speed framing camera photographs, and strain gages. It was found that all fractures were initiated by bending stress; two different fracture patterns in plates were produced experimentally. The plate response was also predicted analytically by numerically integrating the characteristic equations of Mindlin plate theory. It was found analytically that, depending on loading intensity and duration, a total of five fracture patterns in plates, including both those observed experimentally, can be produced by localized impulsive loads.