2017 年 2 巻 p. 141-146
Degeneration of collagen fibres at 60ºC is well known, and therefore mechanical testing of compact bone at the elevated temperatures higher than 60ºC could give us the similar results to that of the degenerated compact bone due to aging. In the present study, a series of fracture toughness tests on compact tension specimens of bovine compact bone under mode I loading has been performed at various temperatures between 50ºC and 70ºC according to ASTM standards. Two types of bone tissue, namely plexiform and Haversian bone were taken from the mid-diaphyseal region of bovine femurs and then tested. An initial crack was introduced in the direction parallel or perpendicular to the long axis of the femur so as to observe anisotropic behaviour. Plexiform bone showed higher fracture toughness than Haversian bone independently of the initial crack direction and temperature. Both compact bones appeared to show lower fracture toughness at higher temperatures. These results were discussed with an assistance of observation of the fracture surfaces using an optical and scanning electron microscope.
