A theoretical and experimental investigation of impulsively loaded clamped circular viscoplastic plates

Abstract

Experiments are described in which clamped circular plates of 6061-T6 aluminum alloy and H.R. steel A285 were subjected to uniformly distributed impulses to cause permanent central deflections ranging from one to several plate thicknesses. A viscoplastic theory of plates is presented that takes into account large deflections; the theory includes the rigid-perfectly plastic plate as a special case. By correlating predicted and experimental permanent deflections of the strain-rate insensitive aluminum and the strain-rate sensitive steel plates it is found that the effects of large deflections (which give rise to significant membrane forces) and strainrate sensitivity are comparably responsible for the deflections being below those predicted by the bending theory of rigid-perfectly plastic plates.