Study of High-cycle Fatigue Properties in Tibia Bovine Bones based on Reliability and Scatter-band Predictions

Document Type: Research Paper

Authors

1 Semnan University

2 Faculty of Mechanical Engineering, Semnan University, Semnan, Iran

3 Department of mechanical Engineering, Faculty of Mechanical Engineering, Semnan University, Semnan, Iran

Abstract

Bones are natural composites, which are consisted of mineral fibers, strengthen the organic matrix. They are exposed to both monotonic and cyclic loadings. Therefore, one failure mechanism could be fatigue phenomenon. In this article, the scatter-band and the reliability of tibia bovine bones were predicted in the load-controlled fatigue condition. The one-point rotary-bending fatigue machine was utilized to carry out standard tests at two different loading levels, 0.4 and 0.6 kg for three various loading frequencies, 10, 20 and 30 Hz for tibia bones. For scatter-band prediction, three confidence levels (85, 90, and 95%) were selected. lower/upper bands were drawn for a selected target function, including the ratio of logarithmic fatigue lifetimes to stress levels. For the reliability prediction, three different distribution functions were considered. Results showed by decreasing the confidence level, the scatter-band would be narrower. Besides, the failure probability generally increased at 0.6 kg of the loading level, when the loading frequency increased.

Keywords