3D constitutive modeling of the biaxial mechanical response of intact and layer-dissected human carotid arteries

Human arteries with non-atherosclerotic intimal thickening consist of three distinct layers: adventitia, media and intima. From a series of axial extension and inflation tests on intact and layer-dissected human carotid arteries (adventitia and media-intima composite), a 3D structurally-based strain-energy function (SEF) is calibrated, and a set of five material parameters is identified which is not yet available in the literature. The zero-stress states of the artery tubes investigated are considered in the calibration process, and the related kinematics for the finite deformation of the individual continuum are described in detail. The SEF employed is capable of describing the different mechanical properties of the intact and layer-dissected tissue tubes (arterial segments) investigated at different pressure domains and axial stretches. The correlation coefficients and error measures determined indicate good correlation between the model and the experimental data for all tested tubes. Mean values of each individual material parameter provide a kind of ‘master model’ that characterizes the mean response of all mechanical data obtained from the human carotid arteries. The material parameters and the 3D constitutive model serve as a foundation for finite element simulations, and hence the analysis of more complex patient-specific boundary-value problems in the human carotid physiology and pathology.