Session: 02-04-02 Extreme Loads and Response 2

Submission Number: 181537

Numerical Study on the Structural Damage of Naval Vessels Under Near-Field Undex 

Ensuring the survivability of naval vessels against near-field underwater explosion (UNDEX) threats is a critical design requirement in modern maritime defense. This study presents an integrated computational framework that performs a comprehensive survivability assessment of naval combatants by sequentially coupling structural damage analysis from a near-field UNDEX with subsequent progressive flooding simulations. The first stage involves nonlinear dynamic analysis of the hull subjected to near-field UNDEX loading. Since hull cavitation and free surface cavitation significantly affect the hull behavior under near-field UNDEX, the fluid domain, explosive charge, and hull were modeled based on the Coupled Eulerian-Lagrangian (CEL) method. The fluid domain and explosive were modeled using Eulerian elements. The behavior of the fluid under high-pressure shock loading was described by the Us-Up equation of state, and the explosive behavior was represented by the Jones-Wilkins-Lee (JWL) equation of state. The hull was modeled with Lagrangian elements. To improve the reliability of the damage analysis, flow stress and fracture criteria were implemented using the combined Swift-Voce model (SV model) and combined Hosford Coulomb - Localized Necking model (HC-LN model). The material properties of these models were determined from actual tests. In the second stage, flooding simulations were conducted based on the structural damage from the near-field UNDEX simulation. These simulations tracked seawater ingress into damaged compartments according to the keel impact coefficient and monitored the ship's trim and heel response histories. Furthermore, a critical keel impact coefficient leading to final sinking due to flooding was proposed. This integrated analysis framework is expected to facilitate structural reinforcement strategies to enhance survivability in future naval vessel designs.

Keywords: Near-field underwater explosion, Coupled Eulerian-Lagrangian, Breach, Progressive Flooding, Survivability

Funding: This research was funded by the Korea Energy Technology Evaluation and Planning and the Korea Ministry of Trade, Industry and Energy (MOTIE) (Nos. 20213000000030, RS-2023-00238996, RS-2024-00450063, and RS-2025-25450859) and by the Korea Ministry of Oceans and Fisheries (MOF) (No. RS-2025-02220608).

Presenting Author: Sujin Oh Inha University

Presenting Author Biography: UNDEX (under water explosion)

Authors:

Sujin Oh Inha University
Hojin Yoon Inha University
Joonmo Choung Inha university