Original scientific paper

https://doi.org/10.21278/TOF.452015320

Application of a Probability Model Based on Paris' Law in Assessing Fatigue Life of Marine High-Strength Steel Structures

Jie Zhang orcid.org/0000-0002-5278-3196 ; College of Ocean Science and Engineering, Shanghai Maritime University, Shanghai, China
Junfeng Gan ; College of Ocean Science and Engineering, Shanghai Maritime University, Shanghai, China
Ying Zeng ; College of Ocean Science and Engineering, Shanghai Maritime University, Shanghai, China

Abstract

Paris' law is a commonly used formula in the assessment of fatigue life of structures. In the present study, we sought to improve the accuracy of this law in marine engineering using a probability model to experimentally assess fatigue life. First, a fatigue crack growth test was performed using compact tension specimens made of marine high-strength steel to obtain a reasonable range of material coefficients C and m in Paris' law. The material coefficient m was then determined as a constant, C followed a log-normal distribution, and Paris' law with different probabilities dependent on C was established. Finally, the probability model based on Paris' law was used to calculate fatigue life of a welded component with a surface crack caused by combined compressive and bending stresses. The results were then compared with the data from a fatigue test that used a crack front marking technique to depict the fractography. The findings of this study show a linear relationship between log C and m that caused a mutual constraint of the material coefficients. In summary, the structure fatigue life calculated by the probability mode based on Paris' law is reliable, thus it can greatly improve safety and accuracy of fatigue life assessment in marine engineering.

Keywords

fatigue life assessment, Paris' law, probability model, surface crack, experiment

Hrčak ID:

262859

URI

https://hrcak.srce.hr/262859

Publication date:

9.7.2021.

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