Parameter identification of the passive response in arteries

This article discusses the passive response of arteries, with a particular focus on the material parameter identification process of constitutive model of anisotropic hyperelasticity. The arterial wall is composed of three layers: tunica intima, tunica media and tunica adventitia. However, only the media and the adventitia are assumed to be mechanically relevant tissue layers. Thus, it is necessary to determine a set of material parameters for each contributing layer, based on inhomogeneous stress-strain state in an experimental setup. In these tests, tensile and internal pressure loading paths are applied on a human mammary artery, which is embedded in a tank filled with Krebs solution. The artery was proved, in previous works, to be slightly compressible and anisotropic. We draw on the model of Nolan et al. (2014) to identify the material parameters, based on the experimental data provided by contour lines and using digital imaging analysis. The experimental protocol is explained in detail. From the experiments, the axial reaction force and displacement in the radial direction are used to determine the material parameters by using finite element simulations. A particular focus lies on the highly correlated solution between material parameters in the layer, emphasizing the extreme difficulties of a “unique” identification.