Hammond Max A, Wallace Joseph M, Allen Matthew R, Siegmund Thomas
Department of Mechanical Engineering, Purdue University, West Lafayette, IN, USA.
Department of Biomedical Engineering, Indiana University-Purdue University at Indianapolis, IN, USA.
J Biomech. 2019 Jan 23;83:34-42. doi: 10.1016/j.jbiomech.2018.11.018. Epub 2018 Nov 16.
Microcracking in trabecular bone is responsible both for the mechanical degradation and remodeling of the trabecular bone tissue. Recent results on trabecular bone mechanics have demonstrated that bone tissue microarchitecture, tissue elastic heterogeneity and tissue-level mechanical anisotropy all should be considered to obtain detailed information on the mechanical stress state. The present study investigated the influence of tissue microarchitecture, tissue heterogeneity in elasticity and material separation properties and tissue-level anisotropy on the microcrack formation process. Microscale bone models were executed with the extended finite element method. It was demonstrated that anisotropy and heterogeneity of the bone tissue contribute significantly to bone tissue toughness and the resistance of trabecular bone to microcrack formation. The compressive strain to microcrack initiation was computed to increase by a factor of four from an assumed homogeneous isotropic tissue to an assumed anisotropic heterogenous tissue.
小梁骨中的微裂纹是小梁骨组织机械性能退化和重塑的原因。近期关于小梁骨力学的研究结果表明，为了获得关于机械应力状态的详细信息，应综合考虑骨组织微结构、组织弹性异质性和组织水平的机械各向异性。本研究调查了组织微结构、弹性方面的组织异质性和材料分离特性以及组织水平各向异性对微裂纹形成过程的影响。使用扩展有限元法建立了微观尺度的骨模型。结果表明，骨组织的各向异性和异质性对骨组织韧性以及小梁骨对微裂纹形成的抵抗力有显著贡献。计算得出，从假定的均匀各向同性组织到假定的各向异性非均匀组织，微裂纹起始的压缩应变增加了四倍。
