Fatigue strength assessment of laser welded thin-walled joints made of mild and high strength steel. (March 2017)

• Record Type: Journal Article
• Authors: Marulo, G.; Baumgartner, J.; Frendo, F.
• Is Part Of: International journal of fatigue. Volume 96(2017)
• Page Start: 142
• Page End: 151
• Publication Date: 2017-03
• Subjects: Fatigue assessment -- High strength steel -- Thin-walled specimens -- Laser beam welds -- Notch stress approach; Materials -- Fatigue -- Periodicals; Materials -- Fatigue; Periodicals; 620.1122
• DOI: 10.1016/j.ijfatigue.2016.11.016
• Languages: English
• ISSNs: 0142-1123

Abstract

Highlights: A database of fatigue tests involving thin-walled laser welded joints is presented. The collected data are analysed based on the fictitious notch radius approach. The base material static properties are related to the fatigue strength. An assessment procedure is suggested joints made of high strength steels. Based on a regression analysis, a new fatigue design curve is proposed. Abstract: A database of fatigue tests taken from literature on thin-walled laser welded joints was created. Fatigue tests related to specimens made of different steel grades were considered, i.e. conventional and high strength steel, which is becoming of more concern in the automotive industry. For each specimen geometry in the database, the stress field in the notch ligament was obtained by means of finite element analysis, where the reference radius of ρ f = 0.05 mm was modelled. The fatigue assessment was performed by using three representative stresses: the maximum notch stress as well as the stress according to the critical distance and the stress averaging approach. For each assessment approach a regression S–N curve with a dedicated scatter band ( T σ ) was obtained. The scatter was taken as measure of the assessment reliability. In addition to the assessment approach, also the effect of the base material on the fatigue strength is discussed.