The boundary between the initiation and the propagation phase of fatigue and the explanation of Threshold region


Mr. Ma Jianxiao

PhD candidate in the Mechanical Engineering Dept.

Date & Time

Tuesday, 12 April 2022

2:00 am


Via Zoom


In fatigue, the boundary between the crack initiation and propagation phases needs to be resolved. The Manson-Coffin equation and the Paris equation are the two fundamental equations, which are used in crack-free and cracked structures, respectively. By transforming these two equations, a relatively reasonable quantitative boundary has been proposed.

When the same idea was used in a cracked structure, the crack growth rate has been calculated by the Manson-Coffin equation containing two parameters——the magnitude of stress intensity factor and the stress ratio. Through the analysis of stress ratio and residual stress, a plausible meaning of the threshold region is explained. Pre-overload experiments show that overload is the cause of the threshold region.

Research Areas:

Advanced Materials

Contact for


Prof. M.X. Huang

+(852) 3917 7906

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