Response of Cellular Core Sandwich Panels to UNDEX Loading: The Influence of Shock Factor Variation

¹ Department of Mechanical Engineering, Universitas Sebelas Maret, Surakarta, Indonesia
² Laboratory of Design and Computational Mechanics, Faculty of Engineering, Universitas Sebelas Maret, Surakarta, Indonesia
³ Research Center for Hydrodynamics Technology, National Research and Innovation Agency (BRIN), Surabaya, Indonesia
⁴ Department of Naval Architecture and Ocean Engineering, Nha Trang University, Nha Trang, Viet Nam
⁵ Department of Civil Engineering, Gifu University, Gifu, Japan

^* Corresponding author: aditya@ft.uns.ac.id

Abstract

The Underwater Explosion (UNDEX) phenomenon generates high-pressure shock waves that pose a serious threat to the structural integrity of ships and marine infrastructure. Building on previous studies that examined the response of sandwich panels with four cellular core configurations under the same Shock Factor (SF) scenario, this study investigates the effect of varying SF resulting from changes in TNT mass while keeping the stand-off distance constant. This approach reflects a realistic condition in which the blast source position remains fixed, but the threat severity increases. Numerical simulations were carried out using a finite element-based coupled acoustic-structural analysis to explore the relationship between increasing SF and the resulting maximum deformation, received impulse, and potential structural damage. The results indicate that a higher SF significantly accelerates the onset of deformation and intensifies local damage. Among the configurations, X-core and U-core demonstrate greater resistance than Y-core, and are markedly superior to S-core, both in terms of lower maximum deflection and reduced impulse. These findings reinforce the conclusions of previous studies and offer valuable insights for optimizing sandwich panel designs to mitigate the impact of UNDEX on critical infrastructure.