Prediction of Failure Envelope of Calcified Aneurysmatic Tissue

Abstract

The abdominal aortic aneurysm (AAA) may have a varying degree of calcification where calcium particles are found in different geometrical configurations. The impact of calcification on the failure of aneurysms is not very clear as literature shows contradictory results. This work is dedicated to investigating the impact of calcification on the failure strength of an aneurysmatic wall using micromechanical finite element simulations. A Representative Volume Elements (RVE) consisting of circular and elliptical particles are generated with different volume fractions, which is further extruded in the thickness direction. A two-fibre model is used for modeling anisotropic tissues. Calcium particles are assumed to be elastic. An anisotropic phase-field model is employed to model the failure in the tissue. A unique set of representative material parameters as well as phase-field parameters, like critical fracture energies for isotropic and anisotropic parts, are determined by fitting the model to experimental data, available in the literature. Finite element simulations are being performed on RVEs to generate a failure envelope of the calcified tissues under bi-axial loading conditions. This study will help in better understanding and better prediction of failure in aneurysms.