Nonlinear Viscoelastic Properties and Constitutive Modeling of Blood Vessel

Abstract

The objective of this study is to investigate the mechanical properties of arterial wall harvested for constructing vascular graft, particularly the hyperelasticity and nonlinear viscoelastic properties. Experimental results from our new biomechanical properties tester on human and porcine vascular tissues showed that the tissue behaves hyperelastically. Experiments on porcine arteries revealed that the relaxation of vascular tissue is strain dependent. A recently proposed combined logarithm and polynomial strain energy function was adopted in modeling the hyperelasticity of the vascular tissue. A modified reduced relaxation function is proposed to model the strain dependent relaxation behavior of vascular tissue. This function comprises a new correction factor that correlates the relaxation process at different strain level, and a Prony series function that models the stress relaxation behavior. The strain energy and modified reduced relaxation functions match the experimental data excellently. New experimental protocol on evaluating the degradation in human vascular graft due to cryopreservation has been proposed.