Analysis of Stress and Strain Distribution in the Artery Wall Consisted of Layers with Different Elastic Modulus and Opening Angle

Bovine thoracic aorta is stiffer in the inner wall than in the outer, and its opening angle is larger in the inner layer than in the outer. A model for mechanical analysis of such a heterogeneous artery wall was developed. The wall was assumed to be made of thin, incompressible, homogeneous, and isotropic layers having different elastic properties and opening angle. Stress and strain distributions in the wall were calculated using the opening angle and stress-strain relationship measured in thin sliced layers of bovine thoracic aortas. Stress distribution was uniform under a physiological condition if elastic properties and the opening angle were set uniform. Stress distribution was not uniform under any condition when the material heterogeneity was introduced. Such non-uniformity was reduced if heterogeneity in the opening angle was considered. The opening angle may be higher in the inner wall to compensate stress concentration caused by the material heterogeneity.