An analytical and experimental study on the thickness effect of fatigue strength in large-scale-welded models

• Published in: Welding in the world Vol. 58; no. 3; pp. 329 - 337
• Main Authors: Yamamoto, Norio, Mouri, Masashi, Okada, Tetsuo, Mori, Takeshi
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.05.2014
• Subjects: Chemistry and Materials Science; Materials Science; Metallic Materials; Research Paper; Solid Mechanics; Theoretical and Applied Mechanics; Fatigue tests; Notch effect; Structures; Stress distribution; Fatigue strength
• ISSN: 0043-2288; 1878-6669
• DOI: 10.1007/s40194-014-0118-y

Although “thickness effect” has long been considered to be a weakening factor with respect to fatigue strength, it is still somewhat unclear as to which factors dominate this effect as well as how it is influenced by different structural or joint types and different loading patterns. Using geometric specimens cut from a steel plate, it was confirmed, both through experimentation and the resulting analysis, that not only the stress concentrations but also the stress gradients at weld toes were the dominant factors relevant to thickness effect. These experimental results were verified by fatigue tests of cruciform-welded joints and out-of-plane gusset-welded joints as well as associated analysis (Yamamoto et al. 2012 ). In addition, the thickness effect in large-scale structural models was investigated through structural model fatigue tests and associated analysis, and it was found that the thickness effect in such large models was quite small in comparison to that observed in fatigue tests of small specimens.