Polarization response characteristics of 6061Al under impact loading

Abstract

At present, the mechanism of metal impact polarization is still unclear. A new method for measuring the electric polarization characteristics of metal materials under impact load based on electromechanical theory have been proposed in this paper. The electromechanical response characteristics of 6061Al under different loading conditions, thicknesses and electrode parameters are studied using the split Hopkinson pressure bar (SHPB) system. Combining with the ANSYS/LS-DYNA numerical simulations corresponding to the experimental conditions, the strain gradients and electromechanical coefficients of 6061Al with different thicknesses and electrode geometric parameters are obtained. The results show that polarization voltages first increase then decrease with time, but their maximum value is first decreases then increases with the increasing of loading speed; the polarization voltages of 6061Al with cross-shaped electrode are larger than that with annular notched electrode or fully covered electrode; with the increasing of strain rate, the response times of the maximum polarization voltage time t(${U_{{\text{Max}}}}$) and the maximum strain ratio time t(${\dot {\varepsilon }_{{\text{Max}}}}$) are increased; the strain gradients decrease with the increasing of thickness but the polarization intensities tend to be opposite; the polarization intensities of 6061Al with fully covered electrodes and annular notch electrodes are close, however, the polarization intensities of 6060Al with cross-shaped electrode are larger; the electromechanical coefficients of 6061Al are about 10⁻²–10¹ C/m.