D4 Published development or research report or study

Fatigue analysis on the transverse fillet-welded joints made of ultra-high-strength steel - mean stress correction using 4R method (IIW-Doc. XIII-2779-19)

Publication Details
Authors: Ahola Antti, Skriko Tuomas, Björk Timo
Publishing place: International Institute of Welding
Publication year: 2019
Language: English
JUFO-Level of this publication: 0
Open Access: Not an Open Access publication


Fatigue analysis on the experimentally tested transverse fillet-welded non-load-carrying T- and X-joints made of S960 and S1100 ultra-high-strength steel (UHSS) was carried out in the present study. The test series consisted welded joints in the as-welded (AW), high frequency mechanical impact (HFMI)-treated, and tungsten inert gas (TIG)-dressed condition. The fatigue tests were carried out using uniaxial constant amplitude loading (CAL) with applied stress ratio of R = 0.1–0.5. The weld geometry and residual stress measurements were carried out, and for each joint, the fatigue strength was assessed using the 4R method, in which the cyclic elastic plastic behavior was obtained considering the applied notch stress Δσk based on weld toe radius r, material ultimate strength Rm, residual stress σres, and the applied stress ratio R of external loading. The Smith-Watson-Topper (SWT) parameter is applied to conduct a mean stress correction to commeasure all results into a single S-N curve. The results showed R-dependency of the fatigue strength capacity for both joints in the AW and PWT condition when using the conventional stress-based approaches, i.e. nominal stress, structural hot-spot (HS) stress and effective notch stress concepts. Nevertheless, the 4R method resulted in a good agreement between the experimental test results and the fatigue strength assessment regardless of the load and joint conditions.

Last updated on 2020-03-02 at 12:51

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