Nims Robert J, Durney Krista M, Cigan Alexander D, Dusséaux Antoine, Hung Clark T, Ateshian Gerard A
Department of Biomedical Engineering , Columbia University , 500 West 120th Street, MC4703, New York, NY 10027 , USA.
Department of Mechanical Engineering , Columbia University , 500 West 120th Street, MC4703, New York, NY 10027 , USA.
Interface Focus. 2016 Feb 6;6(1):20150063. doi: 10.1098/rsfs.2015.0063.
This study presents a damage mechanics framework that employs observable state variables to describe damage in isotropic or anisotropic fibrous tissues. In this mixture theory framework, damage is tracked by the mass fraction of bonds that have broken. Anisotropic damage is subsumed in the assumption that multiple bond species may coexist in a material, each having its own damage behaviour. This approach recovers the classical damage mechanics formulation for isotropic materials, but does not appeal to a tensorial damage measure for anisotropic materials. In contrast with the classical approach, the use of observable state variables for damage allows direct comparison of model predictions to experimental damage measures, such as biochemical assays or Raman spectroscopy. Investigations of damage in discrete fibre distributions demonstrate that the resilience to damage increases with the number of fibre bundles; idealizing fibrous tissues using continuous fibre distribution models precludes the modelling of damage. This damage framework was used to test and validate the hypothesis that growth of cartilage constructs can lead to damage of the synthesized collagen matrix due to excessive swelling caused by synthesized glycosaminoglycans. Therefore, alternative strategies must be implemented in tissue engineering studies to prevent collagen damage during the growth process.
本研究提出了一个损伤力学框架，该框架采用可观测状态变量来描述各向同性或各向异性纤维组织中的损伤。在这个混合物理论框架中，损伤通过已断裂键的质量分数来跟踪。各向异性损伤包含在这样的假设中：材料中可能共存多种键类型，每种键都有其自身的损伤行为。这种方法恢复了各向同性材料的经典损伤力学公式，但对于各向异性材料不采用张量损伤度量。与经典方法相比，使用可观测状态变量来描述损伤使得模型预测能够直接与实验损伤度量进行比较，如生化分析或拉曼光谱分析。对离散纤维分布中损伤的研究表明，对损伤的恢复能力随纤维束数量的增加而增强；使用连续纤维分布模型对纤维组织进行理想化处理会排除损伤建模。这个损伤框架被用于检验和验证以下假设：软骨构建体的生长会由于合成糖胺聚糖引起的过度肿胀而导致合成胶原基质的损伤。因此，在组织工程研究中必须实施替代策略以防止生长过程中胶原的损伤。
