Department of Mechanical Engineering, University of California, Berkeley, USA.
Department of Mechanical Engineering, University of California, Berkeley, USA; Department of Orthopaedic Surgery, University of California, San Francisco, USA.
J Mech Behav Biomed Mater. 2021 Mar;115:104292. doi: 10.1016/j.jmbbm.2020.104292. Epub 2020 Dec 31.
A comprehensive understanding of biological tissue mechanics is crucial for designing engineered tissues that aim to recapitulate native tissue behavior. Tensile mechanics of many fiber-reinforced tissues have been shown to depend on specimen geometry, which makes it challenging to compare data between studies. In this study, a validated multiscale, structure-based finite element model was used to evaluate the effect of specimen geometry on multiscale annulus fibrosus tensile mechanics through a fiber engagement analysis. The relationships between specimen geometry and modulus, Poisson's ratio, tissue stress-strain distributions, and fiber reorientation behaviors were investigated at both tissue and sub-tissue levels. It was observed that annulus fibrosus tissue level tensile properties and stress transmission mechanisms were dependent on specimen geometry. The model also demonstrated that the contribution of fiber-matrix interactions to tissue mechanical response was specimen size- and orientation-dependent. The results of this study reinforce the benefits of structure-based finite element modeling in studies investigating multiscale tissue mechanics. This approach also provides guidelines for developing optimal combined computational-experimental study designs for investigating fiber-reinforced biological tissue mechanics. Additionally, findings from this study help explain the geometry dependence of annulus fibrosus tensile mechanics previously reported in the literature, providing a more fundamental and comprehensive understanding of tissue mechanical behavior. In conclusion, the methods presented here can be used in conjunction with experimental tissue level data to simultaneously investigate tissue and sub-tissue scale mechanics, which is important as the field of soft tissue biomechanics advances toward studies that focus on diminishing length scales.
全面了解生物组织力学对于设计旨在再现天然组织行为的工程组织至关重要。许多纤维增强组织的拉伸力学已被证明取决于标本几何形状，这使得在研究之间比较数据具有挑战性。在这项研究中，使用经过验证的多尺度、基于结构的有限元模型通过纤维参与分析来评估标本几何形状对多尺度纤维环拉伸力学的影响。研究了在组织和子组织水平上，标本几何形状与模量、泊松比、组织应力-应变分布和纤维重新取向行为之间的关系。结果表明，纤维环组织水平的拉伸性能和应力传递机制取决于标本几何形状。该模型还表明，纤维-基质相互作用对组织力学响应的贡献取决于标本的尺寸和方向。这项研究的结果强调了基于结构的有限元建模在研究多尺度组织力学中的优势。这种方法还为研究纤维增强生物组织力学的最佳组合计算实验研究设计提供了指导。此外，这项研究的结果有助于解释以前文献中报道的纤维环拉伸力学的几何依赖性，为组织力学行为提供了更基本和全面的理解。总之，这里提出的方法可以与实验组织水平数据结合使用，同时研究组织和子组织尺度的力学，这在软组织生物力学领域朝着关注缩小尺度的研究方向发展时非常重要。
