Underwater explosion in centrifuge Part II: Dynamic responses of defensive steel plate

Part II of this paper is focused on the dynamic response of a steel plate of the centrifuge model which is fixed on the container. This plate is 5 cm thick, allowing for non-destructive elastic response to all the 19 blasts. Three accelerators and 10 sets of strain gauges are installed on the plate to monitor the acceleration and deformation histories induced by shock waves and bubble oscillations. This article presents the characteristic values measured for shock waves and bubble oscillations response. The detailed information can be found in a database available on the web. In order to obtain the correct acceleration time history, the cut-off frequency of low-pass filtering by Fourier transformation was applied. The results indicated that the acceleration and strain induced by shock wave was nearly unaffected by the increasing gravity, while the effect of gravity has remarkable influence on those induced by bubble oscillation. A preliminary study of comparing the measured dynamic response with numerical simulations has been carried out using ANSYS LS-DYNA. The results captured the dynamic response in terms of characteristics and trends, but deviated in magnitude due the theoretical and technological limitations involved in both the physical and numerical models. It certainly deserves further studies.