The accuracy of thin-shell theory in estimation of aneurysm rupture

If the mechanical stress in the aneurysm wall exceeds the strength of the wall tissue, aneurysm rupture occurs. Therefore, the mechanical stress distribution should be calculated to evaluate the need for surgical intervention to avoid aneurysm rupture. To find the stress distribution in the wall, several methods such as thick-wall and thin-shell theories can be used. The thick-wall theory, using full equilibrium equations, gives the most accurate results. However, because the thick-wall theory is more complicated and takes longer CPU time, usually simpler theories like the thin-shell theory are preferred. In this study, the results of the thick-wall theory are compared with those of the thin-shell theory to evaluate the accuracy of the thin-shell theory in calculating stress distribution. The results show that for many cases the thin-shell theory is not sufficiently accurate, and, thus, the use of the thin-shell theory may be misleading in evaluating the need for surgical intervention.