The Open Mechanical Engineering Journal

2009, 3 : 35-42
Published online 2009 May 13. DOI: 10.2174/1874155X00903010035
Publisher ID: TOMEJ-3-35

Relations between the S-N, ε-N and da/dN-ΔK Curves of Materials

Hai-Jun Shen , Wan-Lin Guo , Jun-Feng Ma and Bao-Tian Zhu
School of Aeronautics and Astronautics, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China.

ABSTRACT

The S-N, ε-N and da/dN-ΔK curves are the basic data of fatigue property for materials, and they are used in the stress-life method, the local strain method and the LEFM (Linear elastic fracture mechanics) crack propagation method to predict fatigue life of structures, respectively. In the present paper, the relations between these fatigue curves and their probability of predicting each other were discussed through several fatigue-life models. The discussed subjects include (1) predicting the S-N curves from the da/dN-ΔK curves of materials, (2) predicting the S-N curves from the ε-N curves, and (3) predicting the da/dN-ΔK curves from the ε-N curves. It is shown that there are certain relations between the S-N, ε-N and da/dN-ΔK curves of materials and it is predictable from one curve to another.

Keywords:

da/dN-ΔK curve, ε-N curve, S-N curve.