Session: 08-01-02 Maneuvering Simulation

Paper Number: 132883

132883 - Rapid Turning and Capsizing Simulation of Ferry Sewol Sailng at a Constant Speed: Application of Fsi Technique and Controlled Propulsion Algorithm 

On April 16, 2014, the Ferry Sewol sank while operating on a regular route between Incheon and Jeju, South Korea. The Maritime Safety Committee of the Society of Naval Architects of Korea (SNAK), composed of ship safety experts, addressed the most likely causes as a reduced hydrostatic stability due to elevated centre of gravity and rapid and excessive steering of rudder. The purpose of this research is to analyze the possibility of rapid turning with rudder angle changes when the Sewol was going at a service speed. To reach this purpose, Abaqus, an explicit-based finite element analysis (FEA) code, was used. FEA is inclusively capable of performing fluid-structure interaction (FSI) analysis without co-simulations with any other software, and can produce relatively accurate results, especially for problems where fluid shear viscosity is not dominant. The FEA model of the Sewol that was provided by the Special Investigation Committee on the Sewol Disaster in April 2022 was in Nastran format. The element size in the Nastran file was longitudinal stiffener spacing. As the purpose of this research is rapid turning simulations, thus all elements were converted to rigid shell elements of R3D3 and R3D4 in Abaqus format. The three center of gravity (CoG) were assumed by referring to some previous investigation reports: GM = 0.724m, 0.603m, and 0.589m. The fluid domain was modeled using Arbitrary Lagrangian Eulerian (ALE) technique. The size of the Eulerian domain of 800m x 800m x 40m, which is regarded sufficiently large enough compared to the investigated automatic identification system data, was determined. The size of the fluid elements was 2m. The total number of fluid elements was 3 million. Since the rudder is one of the structural parts of the ship, the rudder angle should be relative to the ship direction. However, a local coordinate system in FEA should be defined in a global coordinate system. We developed a user-defined subroutine that rebuild a new local coordinate system every time increment after receiving the ship going angle (yaw angle). The actual service speed through FEA simulation was also based on the updated local coordinate system. Based on the FEA modeling above, a rapid turning simulation was performed. This shows that a rapid rudder angle change at a high center of gravity will cause the ship to capsize. The results presented are based on a full rudder angle (35 degrees). In the future, further research is needed to see if there is a possibility of sinking at smaller rudder angle.

Presenting Author: Doyoung Kwon INHA University, Ship and Offshore Sturcture Engineering Lab

Presenting Author Biography: 2018.02 ~ 2024.02 (Expectation) Inha University / Bachelor's Degree

Authors:

Doyoung Kwon INHA University, Ship and Offshore Sturcture Engineering Lab
Joonmo Choung Inha University, Ship and Offshore Structure Engineering Lab