皮质骨的断裂韧化机制：一种实验与数值方法。

Fracture toughening mechanism of cortical bone: an experimental and numerical approach.

机构信息

Shanghai Institute of Applied Mathematics and Mechanics, Shanghai 200072, China.

出版信息

J Mech Behav Biomed Mater. 2011 Oct;4(7):983-92. doi: 10.1016/j.jmbbm.2011.02.012. Epub 2011 Feb 28.

DOI:10.1016/j.jmbbm.2011.02.012

Abstract

In this investigation, the crack propagation mechanisms contributing to the toughness of cortical bone were studied using a combination of experimental and numerical approaches. Compact tension (CT) specimens were prepared from bovine cortical bones to achieve crack propagation in the longitudinal and transverse directions. Stable crack extension experiments were conducted to distinguish the crack growth resistance curves, and virtual multidimensional internal bond (VMIB) modeling was adopted to simulate the fracture responses. Results from experiments indicated that cortical bone exhibited rising resistance curves (R-curves) for crack extension parallel and perpendicular to the bone axis; the transverse fracture toughness was significantly larger, indicating that the fracture properties of cortical bone are substantially anisotropic. Microscopic observations showed that the toughening mechanisms in the longitudinal and transverse directions were different. When the crack grew in the transverse direction, the crack deflected significantly, and crack bifurcations were found at the crack wake, while, in the longitudinal direction, the crack was straight and uncracked ligaments were observed. Numerical simulations also revealed that the fracture resistance in the transverse direction was greater than that in the longitudinal direction.

摘要

在这项研究中，采用实验和数值相结合的方法，研究了皮质骨韧性的裂纹扩展机制。从牛皮质骨中制备紧凑拉伸（CT）试样，以实现沿纵向和横向的裂纹扩展。进行了稳定的裂纹扩展实验，以区分裂纹增长阻力曲线，并采用虚拟多维内键（VMIB）模型模拟断裂响应。实验结果表明，皮质骨在平行和垂直于骨轴的方向上表现出上升的阻力曲线（R 曲线）；横向断裂韧性明显较大，表明皮质骨的断裂性能具有明显的各向异性。微观观察表明，在纵向和横向方向上的增韧机制不同。当裂纹在横向扩展时，裂纹明显偏转，并在裂纹尾迹处发现裂纹分叉，而在纵向方向上，裂纹是直的，并且观察到未开裂的韧带。数值模拟也表明，横向的断裂阻力大于纵向的断裂阻力。