Application studies for fatigue strength improvement of welded structures by high-frequency mechanical impact (HFMI) treatment

Yıldırım, Halid Can; Leitner, Martin; Marquis, Gary; Stoschka, Michael; Barsoum, Zuheir

doi:10.1016/j.engstruct.2015.10.044

Cited by 23 publications

(13 citation statements)

References 22 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The predicted FATs are a little higher for low‐strength steels ( f y < 355 MPa) and a little lower for high‐strength steels ( f y > 950 MPa). Compared with the design proposal, the predictions for low strength steels ( f y < 355 MPa) are approximately one fatigue class (12.5%) higher in the IIW system, and for higher strength steels ( f y > 950 MPa), the predictions are 1–2 fatigue classes higher; elsewhere (355 < f y < 800 MPa), the predictions follow the design proposal.…”

Section: Fatigue Strength Prediction Of Peened Butt Weldsmentioning

confidence: 56%

“…Predicted characteristic S‐N curves corresponding to σ res = −0.255 f u and comparison with proposed FAT classes for R = 0.1 and some experimental results: (a) for lower strength steels, (b) for higher strength steels and (c and d) for ultra‐high‐strength steels. HFMI, high frequency mechanical impact treatment; FAT, IIW fatigue class.…”

Section: Fatigue Strength Prediction Of Peened Butt Weldsmentioning

confidence: 99%

“…This results in a 40% increase in allowable design stress for f y = 355 MPa and 91% increase in design stress for f y = 1000 MPa. Yildirim et al have proposed FAT values for the ENS approach as a function of yield stress, f y for axially loaded HFMI‐treated welds. Their proposal is based on a comprehensive evaluation of published data for welded joints ( f y = 267,…,960 MPa) that have been improved using HFMI‐treatment with an S‐N slope of m = 5.…”

Section: Fatigue Strength Prediction Of Peened Butt Weldsmentioning

confidence: 99%

“…Their proposal is based on a comprehensive evaluation of published data for welded joints ( f y = 267,…,960 MPa) that have been improved using HFMI‐treatment with an S‐N slope of m = 5. Yildirim and Marquis also present an exponential best‐fit formula for the improvement factor as a function of yield strength. Most tests were performed using constant amplitude R = 0.1 axial tension fatigue.…”

Section: Fatigue Strength Prediction Of Peened Butt Weldsmentioning

confidence: 99%

“…For HFMI‐treated welds, Yildirim presented a best‐fit curve (assuming m = 5) for available data (longitudinal, cruciform and butt welds) with an exponential formula that takes into account the effect of yield strength on the fatigue strength at R = 0.1. He noted that the fatigue strength increases by about 12.5% for every 200 MPa increase in f y above the reference value of 355 MPa, with an improvement factor of 1.6 compared with the ASW state FAT200.…”

Section: Fatigue Strength Prediction Of Peened Butt Weldsmentioning

confidence: 99%

See 4 more Smart Citations

A new proposal for assessment of the fatigue strength of steel butt‐welded joints improved by peening (HFMI) under constant amplitude tensile loading

Nykänen

Björk

2015

Fatigue Fract Eng Mat Struct

View full text Add to dashboard Cite

A B S T R A C T Experimental fatigue data for butt-welded joints in as-welded condition and under constant amplitude tensile loading were analysed using the effective notch stress system and a new master curve analysis that takes the local stress ratio, R local , into account. The local stresses needed for computation of R local are calculated with the notch strain approach in conjunction with the reference radius concept. The main focus was to predict with the derived master curve the fatigue strength of peened butt-welded joints. The lowest surface residual stresses after peening were first estimated based on reported measurements and an analytical lower bound result. The predictions showed quite similar strength dependences and FAT values as reported for high-frequency mechanical impact treated welds for applied stress ratio R = 0.1. The benefits of peening reduce faster for higher strength steels when R increases. When R = 0.5, the FATs are practically the same for all steel grades.Keywords butt joint; effective notch stress; fatigue; improvement; local stress ratio; residual stress. N O M E N C L A T U R EASW = as-welded condition ENS = effective notch stress approach FAT = IIW fatigue class, fatigue strength corresponding to two million cycles GMAW = gas metal arc welding HAZ = heat affected zone HFMI, HFP = high frequency mechanical impact treatment (generic term) HSS = high strength steel IIW = International Institute of Welding MSSPD = minimization of the sum of squared perpendicular distances from a line NS = nominal stress approach QC = quenched and cold-formable steel SINTAP = structural integrity assessment procedure SWT = Smith-Watson-Topper approach TIG = tungsten inert gas welding UP = ultrasonic peening (device name) C = fatigue capacity E = Young's modulus f u = ultimate strength, nominal f y = yield strength H = cyclic strain hardening coefficient K f = fatigue effective fatigue stress concentration factor between notch stress and nominal stress K HP = improvement factor K m = structural stress concentration factor Correspondence: T. Nykänen.

show abstract

Section: Fatigue Strength Prediction Of Peened Butt Weldsmentioning

confidence: 56%

Section: Fatigue Strength Prediction Of Peened Butt Weldsmentioning

confidence: 99%

Section: Fatigue Strength Prediction Of Peened Butt Weldsmentioning

confidence: 99%

Section: Fatigue Strength Prediction Of Peened Butt Weldsmentioning

confidence: 99%

Section: Fatigue Strength Prediction Of Peened Butt Weldsmentioning

confidence: 99%

See 3 more Smart Citations

A new proposal for assessment of the fatigue strength of steel butt‐welded joints improved by peening (HFMI) under constant amplitude tensile loading

Nykänen

Björk

2015

Fatigue Fract Eng Mat Struct

View full text Add to dashboard Cite

show abstract

Review of Weld Quality Classification Standard and Post Weld Fatigue Life Improvement Methods for Welded Joints

Bhardwaj

Ratnayake

Keprate

2020

Lecture Notes in Civil Engineering

View full text Add to dashboard Cite

Development of an automated system for adaptive post-weld treatment and quality inspection of linear welds

Mikkelstrup

Kristiansen

2022

Int J Adv Manuf Technol

View full text Add to dashboard Cite

High-frequency mechanical impact (HFMI) treatment is a well-documented post-weld treatment to improve the fatigue life of welds. Treatment of the weld toe must be performed by a skilled operator due to the curved and inconsistent nature of the weld toe to ensure an acceptable quality. However, the process is characterised by noise and vibrations; hence, manual treatment should be avoided for extended periods of time. This work proposes an automated system for applying robotised 3D scanning to perform post-weld treatment and quality inspection of linear welds. A 3D scan of the weld is applied to locally determine the gradient and curvature across the weld surface to locate the weld toe. Based on the weld toe position, an adaptive robotic treatment trajectory is generated that accurately follows the curvature of the weld toe and adapts tool orientation to the weld profile. The 3D scan is reiterated after the treatment, and the surface gradient and curvature are further applied to extract the quantitative measures of the treatment, such as weld toe radius, indentation depth, and groove deviation and width. The adaptive robotic treatment is compared experimentally to manual and linear robotic treatment. This is done by treating 600-mm weld toe of each treatment type and evaluating the quantitative measures using the developed system. The results showed that the developed system reduced the overall treatment variance by respectively 26.6% and 31.9%. Additionally, a mean weld toe deviation of 0.09 mm was achieved; thus, improving process stability yet minimising human involvement.

show abstract

Application studies for fatigue strength improvement of welded structures by high-frequency mechanical impact (HFMI) treatment

Cited by 23 publications

References 22 publications

A new proposal for assessment of the fatigue strength of steel butt‐welded joints improved by peening (HFMI) under constant amplitude tensile loading

A new proposal for assessment of the fatigue strength of steel butt‐welded joints improved by peening (HFMI) under constant amplitude tensile loading

Review of Weld Quality Classification Standard and Post Weld Fatigue Life Improvement Methods for Welded Joints

Development of an automated system for adaptive post-weld treatment and quality inspection of linear welds

Contact Info

Product

Resources

About