Elastic Deformation in Orthotropic Vessels

Abstract

Excursions of the semiaxes were used to define the distortion and shape of the vessel cross section considered for conic and almost conic models. Some describing functions and mensuration expressions closely approximate, yet greatly simplify, calculations of perimeter and cross sections. Theory and experiments with models were in good agreement, but preliminary experiments showed the real case to be more complicated. Physical properties of the pulmonary trunk varied along its axis, growing stiffer toward the periphery. Furthermore, the dimension variations with transmural loading alter concepts of properties derived from measurements of a single diameter. The influence of the pericardium on the deformation of the main pulmonary artery under transmural stress was also explored. It was seen that the pericardium exerts significant restraint on the distortion and volume variations of this vessel. Over normal pressure ranges, removal of the pericardium can result in trunk volumes up to 100% greater than realized with the pericardium intact.