The coronary artery is considered as a cylindrical tube with wall material assumed to be homogenous, orthotropic with Fung-type strain energy function [19]. Considering the residual strains in the arteries [19,20], we denoted the opening angle (central angle of the open sector) as ($2\u2009\Theta 0$) for the artery [21]. The dimensions of the segment at zero stress configuration are designated by initial inner radius (*R*_{i}), outer radius (*R*_{e}), and length of the artery open sector (*L*). When the artery is under an internal pressure (*p*_{i}), external pressure (*p*_{e}), and axial tension (*N*_{o}), the inner radius*,* the outer radius, and the length of artery become (*r*_{i})*,* (*r*_{e}), and (*l*), respectively. The average axial stress is defined as ($\sigma z0$), which is corresponding to an axial elongation of stretch ratio ($\lambda z0$). Using cylindrical coordinates, a material point (*R, Θ, Z*) in the stress-free state (open sector) deforms into the point (*r, θ*, z) in the loaded state
Display Formula

(1)$r=r(R,pi,pe)\u2009;\u2009\u2009\u2009\u2009\u2009\theta =\pi \Theta 0\Theta ;\u2009\u2009\u2009\u2009\u2009\u2009z=\lambda z0Z$