Nonlinear mechanical properties of the human saphenous wall: experimental study and mathematical characterization

Atherosclerosis is one of the cardiovascular system diseases that stems from the arterial epithelial cells damages. So studying the vein and arterial mechanical properties is an essential issue. In this case investigating the behavior of the common artery used for the bypass surgery is more important. Human saphenous vein is one of the vessels that are used in these surgeries. The nonlinear behavior of the tissue has been reported in many studies. However, mathematical models of the behavior of these vessels have not been reported so far. The goal of this study is to characterize the behavior of human saphenous vein using planar uniaxial testing. So eight specimens were obtained from human saphenous and the planar uniaxial tests were performed on the tissue specimens by applying loads along two directions. Then the stress-strain curves achieved from the tests were modeled with a mathematical function and the Young modulus was obtained in both longitudinal and circumferential directions. The specimens showed stiffer behavior in longitudinal direction than circumferential. Then measured data were fitted into both hyperelastic four-parameter Fung-type model and modified Mooney–Rivlin model.