Department of Materials Science and Engineering, Uppsala University, Sweden.
Institute of Biomechanics, ETH-Zürich, Switzerland.
J Mech Behav Biomed Mater. 2022 Nov;135:105446. doi: 10.1016/j.jmbbm.2022.105446. Epub 2022 Sep 15.
Fracture processes of trabecular bone have been studied using various approaches over the years. However, reliable methods to analyse fracture at the single trabecula level are limited. In this study, a digital volume correlation (DVC) and a phase-field fracture model are applied and contrasted for human trabecular bone to analyse its failure under global compression at high resolution. A human trabecular bone sample was fractured in situ under synchrotron-based X-ray micro computed tomography (CT). Reconstructed CT data was then used in DVC algorithms to obtain high-resolution displacement fields in the bone at different load steps. A high-resolution specimen-specific structural mesh was discretized from the CT data and used for the phase-field simulation of the fracturing bone. The DVC analysis showed opening mode cracks as well as shear mode cracks. Strains in cracked regions were analysed. The load distribution in the trabecular structure resulted in two completely separated fracture regions in the sample body. A phenomenon that was also captured in the phase-field model. The results encourage us to believe improvements in boundary conditions and material models are worthwhile pursuing. Findings in this study support further development of a phase-field method to analyse fracture in samples with complex morphology, such as trabecular bone, and the capacity of DVC to quantify strains and slowly growing stable fractures during step-wise loading of trabecular bone.
多年来，人们采用各种方法研究了小梁骨的断裂过程。然而，可靠地分析单根小梁断裂的方法有限。在这项研究中，应用了数字体积相关（DVC）和相场断裂模型，并对人类小梁骨进行了对比分析，以在高分辨率下分析其在整体压缩下的失效情况。对人体小梁骨样本进行了基于同步加速器的 X 射线微计算机断层扫描（CT）的原位断裂。然后，使用重建的 CT 数据在 DVC 算法中获得不同加载步骤下骨内的高分辨率位移场。从 CT 数据中离散出高分辨率的特定于样本的结构网格，并用于模拟断裂骨骼的相场。DVC 分析显示了张开模式裂纹和剪切模式裂纹。分析了裂纹区域的应变。小梁结构中的载荷分布导致样本体中出现两个完全分离的断裂区域。这一现象也在相场模型中得到了捕捉。研究结果鼓励我们相信，改进边界条件和材料模型是值得追求的。本研究的结果支持进一步开发相场方法来分析具有复杂形态的样本（如小梁骨）中的断裂，以及 DVC 量化小梁骨逐步加载过程中应变和缓慢增长稳定断裂的能力。
