Determination of a constitutive relation for passive myocardium: II. Parameter estimation.
In the first paper of this series, we proposed a new transversely isotropic pseudostrain-energy function W for describing the biomechanical behavior of excised noncontracting myocardium. The specific functional form of W was inferred directly from biaxial data to be a polynomial function of two coordinate invariant measures of the finite deformation and five material parameters. In this paper, best-fit values of the material parameters are determined from biaxial data using a nonlinear least-squares regression. These values of the parameters are shown to be well-determined, and the final constitutive relation is shown to have good predictive capabilities. Since the proposed constitutive relation describes much broader classes of in-vitro biaxial data than previously proposed relations, it may be better applicable to analyses of stress in the passive heart.
Humphrey
J D
JD
Department of Mechanical Engineering, University of Maryland, Baltimore 21228.
Strumpf
R K
RK
Yin
F C
FC
D000818:Animals; D001696:Biomechanical Phenomena; D004285:Dogs; D004548:Elasticity; D006321:Heart / Q000502:physiology*; D066298:In Vitro Techniques; D008433:Mathematics; D008955:Models, Cardiovascular; D011237:Predictive Value of Tests; D013314:Stress, Mechanical