Dynamic Strain Evolution around a Crack Tip under Steady- and Overloaded-Fatigue Conditions

Metals

Soo Yeol Lee³  E-Wen Huang¹  Wanchuck Woo²  Cheol Yoon³  Hobyung Chae³  Soon-Gil Yoon³ 

[1] Department of Materials Science and Engineering, National Chiao Tung University, Hsinchu 300, Taiwan; E-Mail:;Neutron Science Division, Korea Atomic Energy Research Institute, Daejeon 305-353, Korea; E-Mail:;Department of Materials Science and Engineering, Chungnam National University, Daejeon 305-764, Korea; E-Mails:

关键词: fatigue;    crack growth;    overload;    stress/strain;    neutron diffraction;   

DOI  :  10.3390/met5042109

来源: mdpi

【 摘 要 】

We investigated the evolution of the strain fields around a fatigued crack tip between the steady- and overloaded-fatigue conditions using a nondestructive neutron diffraction technique. The two fatigued compact-tension specimens, with a different fatigue history but an identical applied stress intensity factor range, were used for the direct comparison of the crack tip stress/strain distributions during in situ loading. While strains behind the crack tip in the steady-fatigued specimen are irrelevant to increasing applied load, the strains behind the crack tip in the overloaded-fatigued specimen evolve significantly under loading, leading to a lower driving force of fatigue crack growth. The results reveal the overload retardation mechanism and the correlation between crack tip stress distribution and fatigue crack growth rate.

【 授权许可】

CC BY   
© 2015 by the authors; licensee MDPI, Basel, Switzerland.