Huyghe J M, van Campen D H, Arts T, Heethaar R M
Department of Biophysics, University of Limburg, Maastricht, The Netherlands.
J Biomech. 1991;24(9):841-9. doi: 10.1016/0021-9290(91)90309-b.
A quasi-linear viscoelastic law with a continuous relaxation spectrum describing triaxial constitutive behaviour of heart muscle tissue is presented. The elastic response of the viscoelastic law is anisotropic, while the relaxation behaviour is assumed isotropic. The law is designed for a biphasic description (fluid-solid) of the myocardial tissue. Biaxial and uniaxial stress-strain curves from the literature are used to evaluate the parameters of the model. The non-linear elastic response, the difference between fibre and cross-fibre stiffness, the phenomenon of stress relaxation, the stiffening of the stress-strain relationship with increasing strain rate and the weak frequency dependency of the dissipated energy during cyclic loading are fairly well described by the proposed law. However, it is found that the model produces realistic values for the dissipated energy during cyclic loading only when relaxation parameter values are chosen which result in an overestimation of the stress relaxation data by more than 100%. This finding may indicate non-quasi-linearity of viscoelasticity of passive heart muscle tissue.
提出了一种具有连续松弛谱的准线性粘弹性定律，用于描述心肌组织的三轴本构行为。该粘弹性定律的弹性响应是各向异性的，而松弛行为假定为各向同性。该定律旨在对心肌组织进行双相描述（流体-固体）。利用文献中的双轴和单轴应力-应变曲线来评估模型参数。所提出的定律能够较好地描述非线性弹性响应、纤维和横向纤维刚度的差异、应力松弛现象、应力-应变关系随应变率增加的硬化以及循环加载过程中耗散能量的弱频率依赖性。然而，发现该模型仅在选择导致应力松弛数据高估超过100%的松弛参数值时，才能产生循环加载过程中耗散能量的实际值。这一发现可能表明被动心肌组织粘弹性的非准线性。
