Honeycomb sandwich panels for centrifugal underwater explosion model tests
Zhuofeng Li, Dequan Lei, Zhijie Huang
Abstract
• Honeycomb sandwich panels (HSPs) are proposed to reduce shock waves and reflection. • Performance of HSPs with different core geometries is examined. • Effects of core direction and layer designs on HSP performance are investigated. • Application of HSP in centrifugal UNDEX model tests on concrete dams is evaluated. Centrifugal model tests serve as a straightforward method to reveal the failure mechanism of concrete gravity dams subjected to underwater explosions (UNDEXs), which has received tremendous attention in recent years. In centrifugal UNDEX model tests, shock waves pose a great risk to the safety of the container and centrifuge apparatus, and the wave reflection significantly influences the experimental results. However, no research in the open literature has been conducted to address these issues. Therefore, this study aims to propose honeycomb sandwich panels (HSPs) to reduce reflected wave pressure and incident shock loads on centrifugal containers, thereby minimising the wave reflection effect and protecting the centrifuge apparatus. In this study, HSP numerical models were first established in LS-DYNA and calibrated. After verification of the numerical models, the performance of the proposed HSPs was then investigated, focusing on the reflected waves, deformation, energy absorption, and transmitted force. The numerical results indicate that the HSP with a 4-pointed star-like geometry (Case 4 in this study) in a horizontal placement direction exhibits the best performance in reducing the reflected wave pressure and transmitted force to the container. The proposed HSPs could reduce the peak reflected wave pressure by up to 73.3 %, transmitted force by up to 94 %, and the peak displacements of the dam and centrifugal container by up to 40 % and 90.3 %, respectively. This study offers an improved methodology to mitigate the wave reflection effect on experimental results and reduce incident shock loads on containers in centrifugal UNDEX model tests.