ANISOTROPY OF THE AORTIC TISSUE IN THE AXIAL AND TRANSVERSE DIRECTIONS

Abstract

Mechanical properties of the porcine aortic tissue were studied by subjecting circumferential and longitudinal strips of the tissue to uniaxial states of stress. Stress-strain curves and transverse strain vs. axial strain curves were obtained for strips in the circumferential (θ) and longitudinal (z) directions. The fact that these curves were distinct suggested anisotropic behavior of the tissue. To quantify the degree of separation of these curves directly, indexes of anisotropy were computed as ratios of stresses and strains in the θ and z directions at equal values of axial strains or stresses. It is shown that various stress and strain ratios, which would have a uniform value of unity if the tissue were isotropic, are far from having a constant value of one.