Residual Stress Around Outer Cortical Region in Bovine Femoral Diaphysis

Abstract

The aim of this study is to measure residual stress in bone tissue. Bone tissue is a composite material composed of mineral crystals and collagen.. fibers. Bone mineral is mostly composed of hydroxyapatite (HAp). The interplanar spacing of HAp crystals can be noninvasively measured using the X-ray diffraction method. The residual stress of bone tissue can be calculated from the interplanar spacing. In this work, the sin²ψ method of X-ray diffraction was applied to calculate the residual stresses in bone tissue. This method needs not the value of non-stressed state. In the experiment, distributions of residual stress for bone axial direction were measured around outer cortical regions in bovine femoral shaft. As a result, it was confirmed that the residual stress existed in the surface cortical region of bovine femur for bone axial direction. These stresses were tensile and distributed around the circumferential region. Moreover distributions of these stresses were different between proximal, medial and distal sections of the diaphysis.