Correlation of Crack Initiation Parameters with Life Estimation for Very-High-Cycle Fatigue of High Strength Steels

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	Correlation of Crack Initiation Parameters with Life Estimation for Very-High-Cycle Fatigue of High Strength Steels
	Hong YS(洪友士); Sun CQ(孙成奇); Zhao AG(赵爱国); Youshi Hong
	2011
会议名称	第18届国际计算与实验科学工程大会（International Conference on Computational and Experimental Engineering and Scinece）（ICCES’2011）
会议日期	April 18-21, 2011
会议地点	Nanjing, China
关键词	Very-high-cycle fatigue high strength steels crack initiation fatigue life estimation FGA
通讯作者	Youshi Hong
中文摘要	The researches on the behavior of very-high-cycle fatigue (VHCF) for high strength steels have become a new branch in the field of metal fatigue since 1980s. The characteristics of crack initiation and propagation for high strength steels in VHCF regime differ from those in low cycle and high cycle fatigue regimes. One of the most distinct phenomena for VHCF regime is the interior or subsurface crack initiation at inclusions or at other inhomogeneities. In fact, the period of crack initiation and early growth dominates the fatigue life, which is extremely evident for the fatigue process containing VHCF regime. This paper attempts to further investigate the crack initiation with the morphology of so-called fish-eye and fine granular area (FGA) or optical dark area (ODA) for high strength steels. Fatigue tests were carried out on a high carbon low alloy steel by using rotating bending (52.5Hz) and ultrasonic push-pull (20kHz) machines and the fatigue fracture surfaces were examined by scanning electron microscopy. The present results together with the previous ones showed the data of the stress intensity factor range (SIF) as a function of the dimension for fish-eye and FGA. The results also showed the data of FGA dimension as a function of related inclusion size. Based on the present results and the ones from literature, two models of fatigue life estimation were developed. One was taking into account the size of plastic zone at crack tip in relation with the value of SIF at FGA. The other was considering the fatigue damage cumulative process in relation with the microscopic parameters (inclusion size and FGA size) at the fracture region along with macroscopic quantities (tensile strength and stress level). The estimations are in good agreement with experimental results.
会议录	International Conference on Computational and Experimental Engineering and Scinece
学科主题	固体力学
语种	英语
内容类型	会议论文
源URL	[http://dspace.imech.ac.cn/handle/311007/47036]
专题	力学研究所_非线性力学国家重点实验室
通讯作者	Youshi Hong
推荐引用方式 GB/T 7714	Hong YS,Sun CQ,Zhao AG,et al. Correlation of Crack Initiation Parameters with Life Estimation for Very-High-Cycle Fatigue of High Strength Steels[C]. 见:第18届国际计算与实验科学工程大会（International Conference on Computational and Experimental Engineering and Scinece）（ICCES’2011）. Nanjing, China. April 18-21, 2011.