Buckling failure of rectangular oil tank with corrugated wall

• Main Author: Kek, Shin Mei
• Other Authors: Ong Lin Seng
• Format: Final Year Project
• Language: English
• Published: 2017
• Subjects: DRNTU::Engineering::Mechanical engineering
• Online Access: http://hdl.handle.net/10356/71120
• Institution: Nanyang Technological University

Corrugated wall in oil tankers exhibit many advantages such as lower mass, easier maintenance and smaller corrosive problems. In addition, corrugated construction in the tank wall can enhance lateral flexibility and vertical rigidity. The lateral flexibility enables the tank wall to accommodate a larger inward or outward movement of the wall and the vertical structural rigidity provides a high buckling resistance vertically. This makes them very popular for usage in oil tank. However, local buckling of the corrugated tank wall may happen when there is over pressure loading on the tank wall. It happens suddenly and causes large deformation of the structure in the buckled region. In this present case, the sudden (inward or outward) movement of the tank wall due to buckling would cause pulling-in action of the wall and large rotation at the welded joints at the top/bottom edges of the tank and brought about a secondary failure therein. It is evident that the local buckling failure of the corrugated tank wall is caused by over-pressure loading on the tank wall. This project tackles the challenge to carry out buckling analysis on oil tank with corrugated wall and to determine the buckling load. In the analysis, the corrugated wall of the rectangular oil tank is modelled using the finite element software. Only the buckled wall is modelled, the two vertical edges and the bottom edges are assumed to be fully fixed. Moreover, the top edge is assumes to be simply supported. In the analysis, the tank is assumed to be fully filled with and oil and incremented surcharge pressure is applied until the wall buckles. Two buckling analysis are attempted- the linear buckling (eigenvalue analysis) and non-linear buckling analysis (large displacement analysis). For both analysis, the location of the buckled region has been accurately predicted as compared to the actual. However, the non-linear buckling analysis predicts the buckling pressure closer to the actual being observed.