Puso M A, Weiss J A
Methods Development Group, Lawrence Livermore National Laboratory, CA 94550, USA.
J Biomech Eng. 1998 Feb;120(1):62-70. doi: 10.1115/1.2834308.
The objective of this work was to develop a theoretical and computational framework to apply the finite element method to anisotropic, viscoelastic soft tissues. The quasilinear viscoelastic (QLV) theory provided the basis for the development. To allow efficient and easy computational implementation, a discrete spectrum approximation was developed for the QLV relaxation function. This approximation provided a graphic means to fit experimental data with an exponential series. A transversely isotropic hyperelastic material model developed for ligaments and tendons was used for the elastic response. The viscoelastic material model was implemented in a general-purpose, nonlinear finite element program. Test problems were analyzed to assess the performance of the discrete spectrum approximation and the accuracy of the finite element implementation. Results indicated that the formulation can reproduce the anisotropy and time-dependent material behavior observed in soft tissues. Application of the formulation to the analysis of the human femur-medial collateral ligament-tibia complex demonstrated the ability of the formulation to analyze large three-dimensional problems in the mechanics of biological joints.
这项工作的目标是开发一个理论和计算框架，将有限元方法应用于各向异性、粘弹性软组织。准线性粘弹性（QLV）理论为该框架的开发提供了基础。为了实现高效且简便的计算，针对QLV松弛函数开发了离散谱近似。该近似提供了一种用指数级数拟合实验数据的图形方法。为韧带和肌腱开发的横向各向同性超弹性材料模型用于弹性响应。粘弹性材料模型在通用非线性有限元程序中实现。通过分析测试问题来评估离散谱近似的性能以及有限元实现的准确性。结果表明，该公式能够再现软组织中观察到的各向异性和随时间变化的材料行为。将该公式应用于人体股骨 - 内侧副韧带 - 胫骨复合体的分析，证明了该公式分析生物关节力学中大型三维问题的能力。
