Mechanics of Soft Biological Systems Laboratory, Department of Engineering Science and Mechanics, Virginia Tech, Blacksburg, VA 24061, USA.
Ann Biomed Eng. 2012 Dec;40(12):2541-50. doi: 10.1007/s10439-012-0596-2. Epub 2012 May 31.
A novel constitutive model that describes stress relaxation in transversely isotropic soft collagenous tissues such as ligaments and tendons is presented. The model is formulated within the nonlinear integral representation framework proposed by Pipkin and Rogers (J. Mech. Phys. Solids. 16:59-72, 1968). It represents a departure from existing models in biomechanics since it describes not only the strain dependent stress relaxation behavior of collagenous tissues but also their finite strains and transverse isotropy. Axial stress-stretch data and stress relaxation data at different axial stretches are collected on rat tail tendon fascicles in order to compute the model parameters. Toward this end, the rat tail tendon fascicles are assumed to be incompressible and undergo an isochoric axisymmetric deformation. A comparison with the experimental data proves that, unlike the quasi-linear viscoelastic model (Fung, Biomechanics: Mechanics of Living Tissues. Springer, New York, 1993) the constitutive law can capture the observed nonlinearities in the stress relaxation response of rat tail tendon fascicles.
提出了一种新的本构模型，用于描述韧带和肌腱等各向异性软组织的应力松弛行为。该模型是在 Pipkin 和 Rogers（1968 年，《力学与物理固体学报》，16：59-72）提出的非线性积分表示框架内构建的。它与生物力学中的现有模型不同，因为它不仅描述了胶原蛋白组织的应变相关的应力松弛行为，还描述了它们的有限应变和横向各向同性。为了计算模型参数，在大鼠尾腱束上收集了轴向应力-应变数据和不同轴向拉伸下的应力松弛数据。为此，假设大鼠尾腱束是不可压缩的，并经历等容轴对称变形。与实验数据的比较证明，与准线性粘弹性模型（Fung，Biomechanics: Mechanics of Living Tissues. Springer, New York, 1993）不同，本构定律可以捕捉到大鼠尾腱束的应力松弛响应中的观察到的非线性。
