Abstract

The cortical bone is a hierarchical composite material that, at the microscale, is segmented in an interstitial matrix, cement line, osteons, and Haversian canals. The cracking of the structure at this scale directly influences the macro behavior, and, in this context, the cement line has a protagonist role. In this sense, this work aims to simulate the crack initiation and propagation processes via cortical bone microstructure modeling with a two-dimensional mesh fragmentation technique that captures the mechanical relevance of its constituents. In this approach, high aspect ratio elements are inserted between the regular constant strain triangle finite elements to define potential crack paths a priori. The crack behavior is described using a composed damage model with two scalar damage variables, which is integrated by an implicit-explicit (Impl-Ex) scheme to avoid convergence problems usually found in numerical simulations involving multiple cracks. The approach’s capability of modeling the failure process in cortical bone microstructure is investigated by simulating four conceptual problems and one example based on a digital image of an experimental test. The results obtained in terms of crack pattern and failure mechanisms agree with those described in the literature, demonstrating that the numerical tool is promising to simulate the complex failure mechanisms in cortical bone, considering the properties of its distinct phases.

中文翻译：

---

使用网格破碎技术对皮质骨微结构裂纹进行计算建模

摘要

皮质骨是一种分层复合材料，在微观尺度上被分割成间质基质、骨水泥线、骨和哈弗氏管。这种规模的结构开裂直接影响宏观行为，在这种情况下，水泥线起着主角的作用。从这个意义上说，这项工作旨在通过皮质骨微结构建模来模拟裂纹萌生和扩展过程，并采用二维网格破碎技术来捕获其成分的机械相关性。在这种方法中，高纵横比单元被插入到规则恒应变三角形有限元之间，以先验地定义潜在的裂纹路径。使用具有两个标量损伤变量的组合损伤模型来描述裂纹行为，该模型通过隐式-显式 (Impl-Ex) 方案进行集成，以避免涉及多个裂纹的数值模拟中常见的收敛问题。通过模拟四个概念问题和一个基于实验测试数字图像的示例，研究了该方法模拟皮质骨微结构失效过程的能力。在裂纹模式和失效机制方面获得的结果与文献中描述的结果一致，表明考虑到皮质骨不同相的特性，该数值工具有望模拟皮质骨中的复杂失效机制。