Petalling of plates under explosive and impact loading

Failure by petalling occurs when thin plates are struck by cylindro-conical projectiles. Similar deformation mode is produced by a localized explosion on a plate. In either case, high circumferential strains induced in the ta rget material cause radial cracking and the subsequent rotation of the affe cted plate material resulting in a number of symmetric petals. A new analyt ical method of treating this problem is proposed by developing a simple and realistic velocity and displacement fields. The progressive tearing is qua ntified using the CTOD criterion while bending deformation of cylindrical p etals is described by the propagating hinge line with decreasing local curv ature. The above two modes are coupled through the local bent radius of the petal. Closed form solution is derived for the total energy absorbed by th e system, the number of petals, and the final deformed shape of the plate a s a function of plate flow stress, thickness, and parameters of the externa l loading. The present solution compares well with experimental results of Nurick and Radford (In: Reddy ED (editor) Recent developments in computatio nal and applied mechanics. A volume in honour of John B. Martin. 1997: p. 2 76-301) and Landkof and Goldsmith (Int J Solids Struct 1993;21:245-66) as w ell as empirical equations published in the literature. (C) 1999 Elsevier S cience Ltd. All rights reserved.