Comparison of biomechanical failure criteria for abdominal aortic aneurysm.

Abstract

Medical doctors consider a surgery option for the expanding abdominal aortic aneurysm (AAA) when its maximum diameter reaches 5.5cm. This simple geometrical criterion may possibly underestimate the risks of rupture of small aneurysms as well as overestimate the risks of rupture of large aneurysms. Biomechanical criteria of the AAA failure are desired. Various local criteria of the AAA failure are used in the literature though their experimental validation is needed. In the present work, we use the experimentally calibrated AAA model, which includes a failure description, to examine various popular criteria of the local failure. Particularly, we analyze various states of the biaxial tension of the AAA material and evaluate the following criteria of the local failure: (1) the maximum principal stretch; (2) the maximum principal stress; (3) the maximum shear stress; (4) von Mises stress; and (5) the strain energy. The results show that the strain energy is almost constant for the failure states induced by the loads varying from the uniaxial to the equal biaxial tension. The von Mises stress exhibits a wider range of scattering as compared to the strain energy. The maximum stresses and stretches vary significantly with the variation of loads from the uniaxial to the equal biaxial tension.