MECHANICAL PROPERTIES ALONG THE BRANCHING SITE OF THE ABDOMINAL AORTA AND ILIAC ARTERIES

摘要

There is a great interest in studying arteries due to the prevalence of arterial diseases such as atherosclerosis and aneurysms, but much of the focus has been on straight arteries [1,2]. As arteries branch off, the fiber alignment and thickness of the arterial wall change. Smooth muscle cells orient helically in straight segments while multiple orientations have been seen at the branching region. As a result, straight segments of arteries vary mechanically from branched, segments [2]. This study focused on the structural and mechanical properties of arteries at branching sites to observe the effect of the structural changes at bifurcations on mechanical behavior.Experiments were performed with porcine tissue specimens at the point where the abdominal aorta branches into the iliac arteries and also upstream and downstream of this branching site. Planar equibiaxial mechanical testing in conjunction with video imaging was used to determine the stress and strain of tissue samples during biaxial tension. Strain tracking was performed with markers on the samples. The biaxial testing device pulled with constant displacement rates on each axis and recorded forces. The First Piola-Kirchhoff stress was calculated and studied in relation to the stretch ratio. The nonlinear behavior of the tissues along with differences in properties between the circumferential and longitudinal directions were analyzed.