TY - JFULL AU - Hynek Chlup and Lukas Horny and Rudolf Zitny and Svatava Konvickova and Tomas Adamek PY - 2008/9/ TI - Constitutive Equations for Human Saphenous Vein Coronary Artery Bypass Graft T2 - International Journal of Biomedical and Biological Engineering SP - 271 EP - 275 VL - 2 SN - 1307-6892 UR - https://publications.waset.org/pdf/5594 PU - World Academy of Science, Engineering and Technology NX - Open Science Index 20, 2008 N2 - Coronary artery bypass grafts (CABG) are widely studied with respect to hemodynamic conditions which play important role in presence of a restenosis. However, papers which concern with constitutive modeling of CABG are lacking in the literature. The purpose of this study is to find a constitutive model for CABG tissue. A sample of the CABG obtained within an autopsy underwent an inflation–extension test. Displacements were recoredered by CCD cameras and subsequently evaluated by digital image correlation. Pressure – radius and axial force – elongation data were used to fit material model. The tissue was modeled as onelayered composite reinforced by two families of helical fibers. The material is assumed to be locally orthotropic, nonlinear, incompressible and hyperelastic. Material parameters are estimated for two strain energy functions (SEF). The first is classical exponential. The second SEF is logarithmic which allows interpretation by means of limiting (finite) strain extensibility. Presented material parameters are estimated by optimization based on radial and axial equilibrium equation in a thick-walled tube. Both material models fit experimental data successfully. The exponential model fits significantly better relationship between axial force and axial strain than logarithmic one. ER -