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




View Article   Export Citation:Plain Text | RIS | Endnote


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


[1] Germanischer Lloyd, Rules and Regulations IV, Non-marine Technology, Part 2: Offshore Wind Energy, Hamburg, Germanischer Lloyd Industrial Services, 2004.

[2] Statnikov, E.S. et al., “Ultrasonic Impact Tool for Strengthening Welds and Reducing Residual Stresses”, New Physical Methods of Intensification of Technological Processes, 1977.

[3] Statnikov, E.S. et al., “Applications of Operational Ultrasonic Impact Treatment (UIT) Technologies in Production of Welded Joints”, IIW, Doc. XIII-1668-97, International Institute of Welding, Paris, France, 1997.

[4] Applied Ultrasonics, “Esonics Ultrasonic Impact Treatment: Technical Procedure Document”, Applied Ultrasonics, Birmingham, AL, USA, 2002.

[5] Wichers, M., “Schweißen unter einachsiger, zyklischer Beanspruchung – experimentelle und numerische Untersuchungen”, PhD-thesis, Institute for steel construction, TU Braunschweig, Germany, 2006.

[6] Goldak, J. et al., “A New Finite Element Model for Welding Heat Sources”, Metallurgical Transactions B, 1984, Vol. 15B, pp. 299-305.

[7] Radaj, D., Sonsino, C.M., Fricke, W., “Fatigue Assessment of Welded Joints by Local Approaches”, Second Edition, Woodhead Publishing Limited and CRC Press LLC, 2006.

[8] Bäumel, A., Seeger, T., “Materials Data for Cyclic Loading”, Suppl. 1, Amsterdam, Elsevier Science, 1990.

[9] Neuber, H., “Über die Berücksichtigung der Spannungskonzentration bei Festigkeitsberechnungen, Konstruktion”, 1968, Vol. 20, No. 7, pp. 245-251.

[10] FKM Guideline, Rechnerischer Festigkeitsnachweis für Maschinenbauteile, Germany, 2002.

[11] Schaumann, P., Keindorf, C., “Enhancing Fatigue Strength by Ultrasonic Impact Treatment for Welded Joints of Offshore Structures”, Third International Conference on Steel and Composite Structures (ICSCS07), Manchester, UK, 2007.