A numerical study of dehydration induced fracture toughness degradation in human cortical bone
A numerical study of dehydration induced fracture toughness degradation in human cortical bone
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DOI：
10.1016/j.jmbbm.2024.106468
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发表时间：
2024-03-16
影响因子：
3.9
通讯作者：
Gludovatz，Bernd
中科院分区：
文献类型：
--
作者：
Shin，Mihee;Martens，Penny J.;Gludovatz，Bernd
开发了二维平面应变扩展有限元法 (XFEM) 模型来模拟在水合和脱水条件下进行的人体骨骼三点弯曲断裂韧性测试。使用 XFEM 损伤模型模拟通过显微 CT 成像观察到的骨微观结构和裂纹路径。在水合和脱水条件下推导了骨、基质和骨水泥线的临界损伤应变，结果发现脱水使临界损伤应变降低了约 50%。随后使用各种微观结构模型进行参数研究，以了解各个临界损伤应变变化对断裂行为的影响。研究揭示了在裂纹扩展的早期阶段，水泥线临界损伤应变对裂纹路径和断裂韧性的显着影响。此外，发现在水合环境中，裂纹扩展阻力和裂纹路径对水泥线临界应变值存在显着敏感性，其中水泥线临界应变值的微小变化可以改变裂纹路径，从而显着降低断裂阻力。相反，在韧性较低的脱水状态下，对水泥线临界应变值变化的敏感性较低。总的来说，我们的 XFEM 模型能够为脱水如何影响骨折的微观机制提供新的见解，并且这种方法可以进一步扩展到研究衰老、疾病和药物治疗对骨折的影响。
A 2D plane strain extended finite element method (XFEM) model was developed to simulate three-point bending fracture toughness tests for human bone conducted in hydrated and dehydrated conditions. Bone microstructures and crack paths observed by micro-CT imaging were simulated using an XFEM damage model. Critical damage strains for the osteons, matrix, and cement lines were deduced for both hydrated and dehydrated conditions and it was found that dehydration decreases the critical damage strains by about 50%. Subsequent parametric studies using the various microstructural models were performed to understand the impact of individual critical damage strain variations on the fracture behavior. The study revealed the significant impact of the cement line critical damage strains on the crack paths and fracture toughness during the early stages of crack growth. Furthermore, a significant sensitivity of crack growth resistance and crack paths on critical strain values of the cement lines was found to exist for the hydrated environments where a small change in critical strain values of the cement lines can alter the crack path to give a significant reduction in fracture resistance. In contrast, in the dehydrated state where toughness is low, the sensitivity to changes in critical strain values of the cement lines is low. Overall, our XFEM model was able to provide new insights into how dehydration affects the micromechanisms of fracture in bone and this approach could be further extended to study the effects of aging, disease, and medical therapies on bone fracture.