Schwiedrzik Johann Jakob, Zysset Philippe Kurt
a Institute of Surgical Technology and Biomechanics, University of Bern , Stauffacherstr. 78, CH-3018 Bern , Switzerland.
Comput Methods Biomech Biomed Engin. 2015;18(5):492-505. doi: 10.1080/10255842.2013.818665. Epub 2013 Sep 26.
Prevention and treatment of osteoporosis rely on understanding of the micromechanical behaviour of bone and its influence on fracture toughness and cell-mediated adaptation processes. Postyield properties may be assessed by nonlinear finite element simulations of nanoindentation using elastoplastic and damage models. This computational study aims at determining the influence of yield surface shape and damage on the depth-dependent response of bone to nanoindentation using spherical and conical tips. Yield surface shape and damage were shown to have a major impact on the indentation curves. Their influence on indentation modulus, hardness, their ratio as well as the elastic-to-total work ratio is well described by multilinear regressions for both tip shapes. For conical tips, indentation depth was not statistically significant (p < 0.0001). For spherical tips, damage was not a significant parameter (p < 0.0001). The gained knowledge can be used for developing an inverse method for identification of postelastic properties of bone from nanoindentation.
骨质疏松症的预防和治疗依赖于对骨微观力学行为及其对断裂韧性和细胞介导的适应过程影响的理解。屈服后特性可通过使用弹塑性和损伤模型的纳米压痕非线性有限元模拟来评估。本计算研究旨在确定屈服面形状和损伤对使用球形和锥形压头的骨对纳米压痕深度依赖性响应的影响。结果表明，屈服面形状和损伤对压痕曲线有重大影响。对于两种压头形状，通过多线性回归很好地描述了它们对压痕模量、硬度、它们的比值以及弹性功与总功比值的影响。对于锥形压头，压痕深度没有统计学意义（p < 0.0001）。对于球形压头，损伤不是一个显著参数（p < 0.0001）。所获得的知识可用于开发一种从纳米压痕识别骨弹性后特性的反演方法。
