Session: 06-11-06 Ocean Engineering Technology VI

Paper Number: 132886

132886 - Prediction of Damage Extents for Side Shell Structure of Ferry Sewol During a Batch Lifting Work 

The Sewol ferry, which sank on April 16, 2014, with the loss of more than 300 lives, was salvaged in 2017 and various hull surveys have been conducted since then, but no in-depth study has been conducted on the possible causes of hull damage during seabed landing and ship lifting job. This study aims to analyze the possible hull damage during the seabed landing and lifting of the Sewol. Since the full ship finite element model of the Sewol hull provided by the Special Commission on Social Disaster Investigation in Korea had an element size of longitudinal spacing, a mesh size refinement of 100mmx100mm was performed mainly on the port side where hull damage was observed. Since the hull material was A-grade mild steel, the flow stresses obtained from the tensile test of the material were applied to the hull. The fracture model applied in this study is the Hybrid fracture model of the Hosford - Coulomb and Localized necking, which is known to be most accurate for predicting damages of shell elements. The material constants of this fracture model were obtained through tensile experiments on various tensile specimens. A finite element model was created from the lifting beam drawings provided by the Special Commission on Social Disaster Investigation in Korea. Since no fracture was defined in the lifting beam, an element size of 300mmx300mm was applied. A six-step batch lifting scenario was developed to obtain the cumulative damage to the Sewol ferry during all steps of the lifting process, from seabed landing to underwater lifting. It was confirmed that significant damage could be accumulated even during the seabed landing, and that significant damage was accumulated on the side shell in port. The location and extent of damage based on the batch lifting analyses were also very similar to those of the actual Sewol ferry. The collision with an object such as a submarine at the shallow water depth of the accident area was not practically probable, and the damage in the Sewol's side hull occurred primarily during the seabed landing and lifting.

Presenting Author: Hojin Yoon Department of Ocean Engineering and Naval Architecture, Inha University

Presenting Author Biography: Ho Jin Yoon, Undergraduate Student, Department of Naval Architecture and Ocean Engineering, Inha University, Incheon, Korea
Joon Mo Choung, Professor, Department of Naval Architecture and Ocean Engineering, Inha University, Incheon, Korea

Authors:

Hojin Yoon Department of Ocean Engineering and Naval Architecture, Inha University
Joon Mo Choung Department of Ocean Engineering and Naval Architecture, Inha University