Inelastic failure of fully clamped beams and circular plates under impact loading

Abstract

An experimental investigation is reported on the impact loading of fully clamped mild steel beams and circular plates struck by relatively heavy masses. The impact energies are sufficient in some tests to cause material failure and, thus, to provide the threshold conditions for cracking and severance for impact velocities up to 6.74m/s for beams and 15.66m/s for plates. The beams were struck at several locations across the span, and a significant reduction in the threshold energy is observed for strikes near to a support. Round-nosed impactors require more energy to induce failures than flat-nosed ones. Furthermore, they cause failure to develop at the supports of both beams and plates rather than initiating rupture at the impact point, which is the case for a blunt striker. Reasonable agreement is obtained between the predictions of an elementary theory, which uses rigid-plastic methods of analysis, and the experimental results for the deflection and failure of beams struck at the mid-span. The experimental data, which include static and dynamic material properties, are suitable for calibrating numerical schemes and for further study on the accuracy of criteria for the dynamic inelastic failure of structures.