Johnson G A, Livesay G A, Woo S L, Rajagopal K R
Department of Orthopaedic Surgery, University of Pittsburgh, PA 15261, USA.
J Biomech Eng. 1996 May;118(2):221-6. doi: 10.1115/1.2795963.
A general continuum model for the nonlinear viscoelastic behavior of soft biological tissues was formulated. This single integral finite strain (SIFS) model describes finite deformation of a nonlinearly viscoelastic material within the context of a three-dimensional model. The specific form describing uniaxial extension was obtained, and the idea of conversion from one material to another (at a microscopic level) was then introduced to model the nonlinear behavior of ligaments and tendons. Conversion allowed different constitutive equations to be used for describing a single ligament or tendon at different strain levels. The model was applied to data from uniaxial extension of younger and older human patellar tendons and canine medial collateral ligaments. Model parameters were determined from curve-fitting stress-strain and stress-relaxation data and used to predict the time-dependent stress generated by cyclic extensions.
建立了一个用于描述软生物组织非线性粘弹性行为的通用连续介质模型。这个单积分有限应变（SIFS）模型在三维模型的框架内描述了非线性粘弹性材料的有限变形。得到了描述单轴拉伸的具体形式，然后引入了（在微观层面）从一种材料转换为另一种材料的概念，以模拟韧带和肌腱的非线性行为。转换允许使用不同的本构方程来描述单个韧带或肌腱在不同应变水平下的情况。该模型应用于年轻和老年人类髌腱以及犬内侧副韧带单轴拉伸的数据。通过对应力-应变和应力松弛数据进行曲线拟合来确定模型参数，并用于预测循环拉伸产生的随时间变化的应力。
