http://www.loc.gov/mods/v3 http://www.loc.gov/standards/mods/v3/mods-3-2.xsd
Stress analysis and fatigue evaluation of shell-to-footer plate joint in Liquefied Natural Gas (LNG) storage tanks
xvi, 139 leaves : illustrations ; 28 cm.
Since few new Liquefied Natural Gas (LNG) storage tanks have been constructed since the 1970s, there has been considerable concern for the long-term structural integrity of LNG storage tanks. For this reason, the LNG industry should be able to present documented evidence that the facilities can continue safe operation. This thesis addresses the work involved in the study of the fitness-for-service of the critical vertical shell-to-annular footer plate weld detail of LNG storage tanks when subject to cyclic loading. An attempt is made using the finite element method to numerically predict the structural response of the critical weld joint. Validation of the finite element approach is made by comparing the numerical results with experimental data and a mechanics of materials solution. Using the finite element results, damage tolerance fracture mechanics is used to evaluate flaw stability as the crack propagates from an initial flaw size to a limiting flaw as a result of postulated fatigue crack growth. Seven operational tanks are evaluated with each tank having over a 100 year weekly filling/emptying cycle fatigue lifetime. Furthermore, a parametric fatigue study shows that the fatigue lives of the LNG storage tanks can be extended by increasing the footer plate thickness, inner vertical shell thickness, and/or the flange length. In a general sense, it is seen that by increasing these dimensions that larger initial flaw sizes could be tolerated and still support the conservative 100 year weekly cycling of LNG storage tanks.
"Major subject: Mechanical Engineering".