Effects of strain rate and strain hardening on a cantilever under impact

Abstract

An investigation is carried out to assess the response of elastic–plastic and ductile circular section cantilevers subjected to blast wave loading. A mathematical equation is formulated for the effects of strain rate and strain hardening for ductile (rigid–plastic) cantilever subjected to impact. It is assumed that the cantilever deforms when the moment produced by drag force about the clamped end exceeds the maximum resisting moment of the material, resulting in an equation for deformation. For the transient and modal phase, a correction factor is proposed, which improves the accuracy of response prediction. Full-scale explosion tests are carried out at Woomera (Australia) to investigate the response of cantilevers subjected to air-blast loading, where sixty cantilever test specimens were tested. The test specimens used were designed on the basis of different approaches such as elastic, elasto-plastic, quasi-static, impulse technique and plastic approach. Correction factor ‘K’ for the effects of strain rate and strain hardening were developed and used during the design of cantilever specimens. The prediction of a mathematical model for the response of cantilevers was in line with the response of test specimens during field explosion tests due to the modification factor for the effects of strain rate and strain hardening.