Elastic deformation of a tapered vascular prosthesis

An approximate analysis of the elastic properties of tapered microfibrous polyurethane arterial prostheses is presented by considering a tapered conduit to consist of a series of short cylindrical segments. Using this approach, the relatively simple, non-linear finite deformation models developed for cylindrical arterial specimens may be applied to each segment. A constitutive equation based on a polynomial form of strain energy density function is used in this study. The constitutive constants are determined using experimental data obtained from uniform cylindrical grafts and are used to predict the mechanical response of tapered grafts. The variation in local compliance for linear, tapered grafts of uniform and variable wall thickness is determined. Similarly, the variation in longitudinal strain for tapered grafts subjected to various longitudinal tensions is calculated. The primary purpose of this analysis is to provide data for the design of tapered, compliant vascular grafts. It may also be used to characterize the elastic properties of other non-uniform axi-symmetric elastomeric conduits.