Fatigue strength of repaired cracks in base material of high strength steels. (December 2017)

• Record Type: Journal Article
• Authors: Akyel, A.; Kolstein, M.H.; Bijlaard, F.S.K.
• Is Part Of: Journal of constructional steel research. Volume 139(2017)
• Page Start: 374
• Page End: 384
• Publication Date: 2017-12
• Subjects: Very high strength steels -- Repair weld -- Base material -- Artificial crack -- Fatigue; Steel, Structural -- Periodicals; Building, Iron and steel -- Periodicals; Acier de construction -- Périodiques; Construction métallique -- Périodiques; 624.1821
• DOI: 10.1016/j.jcsr.2017.10.005
• Languages: English
• ISSNs: 0143-974X

Abstract

Abstract: Fatigue crack formation is an inevitable issue for welded steel structures subjected to cyclic loading. Accordingly, repair of the fatigue crack in welded steel structures is unavoidable to prolong fatigue life. However, there is limited knowledge available about the procedure to be adopted for the repair and the life extension to be expected after the repair. The current paper is focused on the effects of the repaired an artificial crack in the base material of S690 and S890 high strength rolled steels on the fatigue strength of the material. An artificial crack was created in the middle of the plate test specimens by spark machining and subsequently, the crack was repaired by using the FCAW (flux-cored arc welding) process. The repaired specimens were tested in a four point bending test rig with a constant amplitude loading for creating a uniform bending moment at the weld region such that the weld cap to be exposed to tensile stresses. The test results show that most of the fatigue cracks initiated at the start-stop points of the weld cap and the fatigue crack initiation life of the specimens occupy approximately 45% of the total fatigue life. The statistical analysis of the test results revealed that the characteristic fatigue strength of the repaired specimens is very close to the detail category 160 of EN 1993-1-9 [5]. Highlights: Fatigue tests are carried out on the repaired base material of very high strength steels. Effects of the repair weld on the fatigue strength of the base material of very high strength steels are analysed. A statistical analysis is performed on the test results to determine S-N curves of the repaired specimens. S-N curves are compared to the detail categories of Eurocode 3 and the fatigue results of the base material.