An analytical model for predicting permanent plastic deflection and strain distributions in aluminium-alloy plates under low velocity impact loading

This paper proposes a new analytical model to predict plastic deformation and strain distributions in aluminium-alloy plates under low velocity impact loading. The low velocity impact load on the fully clamped circular plate was idealized as a quasi-static normal point force acting at the centre of plate. Based on apt geometrical approximation and assumptions, governing equations were established to predict the out-of-plane deflection and the radial tensile, radial and circumferential flexure strains in fully clamped conditions. From the deformation theory of plasticity, a new formula was derived to estimate the impact load by incorporating strain-energy approach, bilinear strain-hardening constitutive model and the one-dimensional Tresca yield criterion. Low velocity impact tests were performed to confirm the proposed model and good correlation was achieved between the predictions and actual experiments, demonstrating the practical and effective use of the proposed model.