Fatigue damage is one of the most serious problems marine structures facing with. Though the S-N assessment for structural fatigue life is a simulative method based on numerous experimental data, it ignores the complicacy of loads on structures. Nevertheless, the fatigue life assessment based on fracture mechanics can consider the effects of stress ratio, overload ratio and load sequence effects, etc., the assessment is reliable, still. In this paper, according to ASTM specification, designed a series of fatigue crack propagation tests by using CT specimens with AH36 high-strength steel for marine structures, and researched simultaneously how overload ratio influence Fatigue crack propagation. Then based on the extended finite element method XFEM, the article made a numerical research on the size of plastic zone at crack tip and calculated by Irwin Formula (a formula used to calculate the size of plastic zone at crack tip), and then make a contradistinction between the results of study and calculation. Ultimately, by using the amended Wheeler Model, the text predicted the crack propagation behavior of AH36 high-strength steel, and compared the applicability of the predictive model with the experimental results. The results show that: the greater the overload, the higher the delayed effect. When the overload reaches 2.5 times, growth of crack almost stops; the accuracy is much high when calculating the size of plastic zone at crack tip by XFEM; revised Wheeler Model made a great depiction of fatigue crack propagation behavior under single overload.
Experimental and Simulate Research on Fatigue Crack Propagation Behavior Under Varying Loadings in High Strength Steel of Marine Structures
Lecture Notes in Civil Engineering
Practical Design of Ships and Other Floating Structures ; 2019 ; Yokohama, Japan September 22, 2019 - September 26, 2019
2020-10-04
18 pages
Aufsatz/Kapitel (Buch)
Elektronische Ressource
Englisch
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