Skacel Pavel, Bursa Jiri
Institute of Solid Mechanics, Mechatronics and Biomechanics, Brno University of Technology, Brno, Czech Republic.
Acta Bioeng Biomech. 2014;16(3):47-58.
Several constitutive models have been proposed for description of mechanical behaviour of soft tissues containing collagen fibres. The model with aligned fibres is modified in this paper to take the dispersion of fibre orientations into account through angular integration and it is compared with the model that is defined through generalized structure tensor. The paper is focused on the effect of fibre dispersion on the resulting stress-strain behaviour predicted by both models analyzed. Analytical calculations are used for the comparison of the mechanical behaviour under a specific biaxial tension mode. The two models have been implemented into commercial finite element code ANSYS via user subroutines and used for numerical simulation resulting in a non-homogeneous stress field. The effects of the fibre dispersion predicted by both models being compared differ significantly, e.g., the resulting stress difference between both models is lower than 10% only in the case of extremely small dispersion of collagen fibres orientation (κ< (0.01 to 0.03)). These results are consistent with those of other related literature. The applicability of the model defined through the generalized structure tensor is discussed.
已经提出了几种本构模型来描述含有胶原纤维的软组织的力学行为。本文对具有排列纤维的模型进行了修改，通过角积分考虑纤维取向的离散性，并将其与通过广义结构张量定义的模型进行比较。本文重点研究纤维离散性对所分析的两个模型预测的应力-应变行为的影响。通过解析计算来比较特定双轴拉伸模式下的力学行为。这两个模型已通过用户子程序在商业有限元代码ANSYS中实现，并用于数值模拟，从而得到非均匀应力场。所比较的两个模型预测的纤维离散性影响差异显著，例如，仅在胶原纤维取向离散性极小（κ<(0.01至0.03)）的情况下，两个模型之间的应力差异才低于10%。这些结果与其他相关文献的结果一致。文中还讨论了通过广义结构张量定义的模型的适用性。
