Abstract
Bone tissue is a composite material composed of hydroxyapatite (HAp) and collagen. Because HAp particles in bone tissue are crystalline structure, an X-ray diffraction method is available to measure the strain of HAp. This work shows, the relationship between lattice strain of HAp crystals and macroscopic strain. In this experiment, strip specimens of 45×6×0.8mm in size with their long axis aligned to the bone axial direction were cut from cortical bone in a shaft of bovine femur. To confirm the relationship between applied macroscopic strain and lattice strain in bone tissue, a tensile device was developed to apply tensile load to the specimen during the X-ray irradiation. Macroscopic strain was measured by a strain-gauge glued on the surface of the specimen. Lattice strain of HAp in the specimen was measured by the X-ray diffraction method. It was found that the lattice strain was generally smaller than the strain macroscopically determined.
