Advanced Steel Construction

Vol. 5, No. 3, pp. 237-258 (2009)



P. Schaumann and C. Keindorf *

Institute for Steel Construction, Leibniz University Hannover

Appelstr. 9A, 30167 Hannover, Germany

*(Corresponding author: E-mail: This email address is being protected from spambots. You need JavaScript enabled to view it.)

Received: 8 October 2007; Revised: 21 January 2008; Accepted: 30 January 2008




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This paper deals with fatigue tests on welded joints carried out in order to estimate the influence of a post weld treatment method called Ultrasonic Impact Treatment. With this method the fatigue resistance could be increased significantly. Furthermore, tubular joints of tripods were analysed with numerical simulations to judge these welded joints with the hot-spot-concept. The stress concentration factor for the treated weld toe geometry was determined numerically and compared to experimental results. In the next step numerical simulations were carried out for seam butt welds using an arc welding process followed by a process of UIT. The objective of these numerical investigations was to analyse the influence of residual stresses on the fatigue life for welded steel plates with and without post weld treatment. The fatigue life until crack initiation was calculated applying the notch strain approach. Both, experimental and numerical investigations attested a significant increase in fatigue resistance due to the post weld treatment by UIT compared to the as-welded condition.



Welded joints, post weld treatment, needle peening, fatigue, uit, offshore, wind energy


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