| Abstract: | Abstract— The use of the hot spot stress approach to the fatigue analysis of welded components is briefly described. Results are presented of fatigue tests on arc welded steel joints (C-Mn and stainless), carried out at Lappeenranta University of Technology between 1980 and 1993, based on the hot spot approach. Based on experimentally-measured hot spot strains, the fatigue capacities of around 100 specimens of C-Mn steel joints, and 80 stainless steel joints, were found to be consistent. The fatigue class FAT 100, or in many cases FAT 112 or higher, can be used as the design hot spot fatigue strength for toe failure of welded joints of moderate thickness, i.e. up to 10 mm. A sharp transition at the fusion zone from the base metal to the weld was clearly shown to be detrimental, leading to a fatigue capacity below average. The log, value of the standard deviation of fatigue life, or the fatigue capacity (Δσ3 N ), was typically 0.13 within a series of C-Mn joints. Statistical analysis of all test data concerning weld toe failure gave a standard deviation of 0.24. By considering all the specimens in one series, a mean fatigue strength of FAT 148, and a characteristic fatigue strength of FAT 107, were obtained. |
