Multi-thickness target plate impact experimental approach to failure waves in soda-lime glass and its numerical simulation

A multi-thickness target plate impact experimental technique is proposed in this paper and adopted in the research on the so-called failure wave phenomenon in soda-lime glasses, in which, four sub-targets in different thicknesses embedded in the target ring are impacted simultaneously and the longitudinal stress temporal curves at the backing surface of each of the sub-targets are measured by four manganin piezo-resistive stress sensors. Hence, the failure wave trajectory under a certain dynamic loading can be obtained by only one test, which can reduce considerably the experimental expense as well as the experimental period, and, more importantly, the measurement uncertainty resulted from different loading conditions in repetitious impact experiments is avoided. It is found that the propagating velocity of failure wave is approximate to a constant and increases with the magnitude of the impact loading, and there always exists an initial delay time for the initiation of failure wave behind the precursory shock wave, which decreases with the magnitude of impact loads. Moreover, a numerical simulation for the failure wave propagation is carried out by using the LS-DYNA applied software, together with a statistical isotropic elastic microcrack model to describe the dynamic damage evolvement of soda-lime glasses. It is demonstrated that both the critical damage value distributions and the free surface particle velocity temporal curves can be used to determine the failure wave trajectory, and the numerical results are consistent substantially with the experimental data.