Fracture and material degradation properties of cortical bone under accelerated stress

The fracture stress and material property degradation of bovine cortical bone specimens were investigated experimentally under accelerated cyclic tensile stress testing. The fracture stress of a typical specimen was found from a static tensile test, and the cyclic loading/unloading was calculated as a percentage of this fracture stress. The results of accelerated cyclic stress tests were compared to monotonically increased static tests to determine if loading/unloading has an effect on the damage mechanism in bone. It was found that fracture stress of the bone increases due to accelerated stress cycling whereas the modulus decreases in a logarithmic fashion with increasing cyclic stress.