The thickness effect of welded details improved by high-frequency mechanical impact treatment

Shams‐Hakimi, Poja; Yıldırım, Halid Can; Al‐Emrani, Mohammad

doi:10.1016/j.ijfatigue.2017.02.023

Cited by 11 publications

(7 citation statements)

References 36 publications

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“…It has been known since the 1950s that fatigue resistance depends on the thickness of the element and that it decreases with an increase in thickness [67]. For thicker panels, a greater volume of material is exposed to high stresses and the fatigue resistance of such details is lower.…”

Section: Influence Of Plate Thicknessmentioning

confidence: 99%

“…Although the effect of element thickness on fatigue life of welded details is known and covered by a variety of standards, this influence has not been systematically investigated for welds treated by HFMI procedures [67]. Guidelines for assessing fatigue of details improved by HFMI treatment are applied for panel thicknesses ranging from 5 to 50 mm [12].…”

Section: Influence Of Plate Thicknessmentioning

confidence: 99%

“…In guidelines [67], an increase of one FAT class is proposed for each 200 MPa increase in the yield strength [72], which has proven to be a conservative assumption. Design recommendations include an increase of four FAT classes for steel joints with yield strength of f y <355 MPa with respect to curves for nominal stresses for the as-welded condition.…”

Section: Influence Of Steel Strengthmentioning

confidence: 99%

“…An allowable increase in the number of FAT classes as a function of yield strength can be found in [12]. Characteristic S-N curves for HFMI treated joints for steels with f y > 355 MPa can be found in [67]. An as-welded joint of high strength steel, e.g.…”

Section: Influence Of Steel Strengthmentioning

confidence: 99%

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High-Frequency mechanical impact treatment of welded joints

2020

JCE

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High-Frequency mechanical impact treatment of welded jointsIn welded structures, fatigue damage often occurs in welds, which are the points of geometrical and material discontinuity. Accordingly, post-weld treatment methods have been developed. One of the relatively new methods is the high-frequency mechanical impact treatment. The method is characterised by the change in weld geometry, local increase in hardness, and elimination of residual stresses generated by the welding process. An overview of this method is provided, and areas requiring further consideration are highlighted.

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Section: Influence Of Plate Thicknessmentioning

confidence: 99%

Section: Influence Of Plate Thicknessmentioning

confidence: 99%

Section: Influence Of Steel Strengthmentioning

confidence: 99%

Section: Influence Of Steel Strengthmentioning

confidence: 99%

See 2 more Smart Citations

High-Frequency mechanical impact treatment of welded joints

2020

JCE

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“…For the fatigue strength of welded structural steel constructions, the geometrical conditions and local boundary layer conditions at the weld seams are decisive. Many studies, e.g., [1][2][3][4][5][6][7][8][9][10][11][12][13], have shown that mechanical surface treatment of welded joints like high-frequency mechanical impact (HFMI) treatment is particularly suitable to improve the fatigue strength of welded steel constructions and can result in an additional weight reduction of steel structures.…”

Section: Introductionmentioning

confidence: 99%

Sequence effect of p(1/3) spectrum loading on service fatigue strength of as-welded and high-frequency mechanical impact (HFMI)-treated transverse stiffeners of mild steel

Schiller¹,

Löschner²,

Diekhoff

et al. 2021

Weld World

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In the meantime, it’s well known that post-weld fatigue strength improvement techniques for welded structures like high-frequency mechanical impact (HFMI) treatment increase the fatigue live of welded joints. Although the current design recommendations for HFMI-treated welded joints give first design proposals for the HFMI-treated welds, in practice the application of HFMI treatment and the associated increase in fatigue resistance are still being discussed. There are, for example, reservations regarding the efficiency of HFMI-treated welded joints under variable amplitude loading (VAL). This paper analyses first results for the sequence effect of VAL of a p (1/3) spectrum on the service fatigue strength of HFMI-treated transverse stiffeners (TS) of mild steel (S355). Fatigue test results with random and high-low loading for the two states as-welded (AW) and HFMI-treated joints will be presented. The modified linear damage accumulation and the failure locations will be discussed. The experimental results show a clear change in the slope of the S-N curve from the as-welded (AW) state to the HFMI state and additionally in the HFMI state from constant amplitude loading (CAL) to variable amplitude loading (VAL). It was particularly noticeable in the experimental results of all tested HFMI series that the specimens failed exclusively in the base material 2–4mm before the HFMI-treated welds. The presented results of the investigations show that with application of the nominal stress concept, no sequence effect was recognizable.

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High‐cycle variable amplitude fatigue experiments and design framework for bridge welds with high‐frequency mechanical impact treatment

2022

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Fatigue enhancement by way of high-frequency mechanical impact (HFMI) treatment can enable effective design and construction of steel bridges. However, bridges may experience high and varying mean stresses, the effects of which are not covered today by any design recommendation or in the literature on HFMI-treated joints. In this study, fatigue experiments were conducted with realistic in-service bridge loading, which revealed the same high fatigue performance as for constant amplitude loading. The effect of mean stress in spectrum loading was quantified and a method to account for it in an equivalent manner is proposed. A design framework has been developed for design and engineering purposes.

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The thickness effect of welded details improved by high-frequency mechanical impact treatment

Cited by 11 publications

References 36 publications

High-Frequency mechanical impact treatment of welded joints

High-Frequency mechanical impact treatment of welded joints

Sequence effect of p(1/3) spectrum loading on service fatigue strength of as-welded and high-frequency mechanical impact (HFMI)-treated transverse stiffeners of mild steel

High‐cycle variable amplitude fatigue experiments and design framework for bridge welds with high‐frequency mechanical impact treatment

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