Issue 41

T. Morishita et alii, Frattura ed Integrità Strutturale, 41 (2017) 45-53; DOI: 10.3221/IGF-ESIS.41.07 45 Focused on Multiaxial Fatigue Evaluation and visualization of multiaxial fatigue behavior under random non-proportional loading condition Takahiro Morishita Postdoctoral researcher, Department of Mechanical Engineering, College of Science & Engineering, Ritsumeikan University, Japan morisita@gst.ritsumei.ac.jp Fumio Ogawa Assistant professor, Department of Mechanical Engineering, College of Science & Engineering, Ritsumeikan University, Japan ogawa-f@fc.ritsumei.ac.jp Takamoto Itoh Professor, Department of Mechanical Engineering, College of Science & Engineering, Ritsumeikan University, Japan itohtaka@fc.ritsumei.ac.jp A BSTRACT . In cyclic multiaxial stress/strain condition under non- proportional loading in which principal direction of stress/strain are changed in a cycle, it becomes difficult to analyze stress/strain ranges because of complexity of multiaxial stress/strain states depending on time in cycles. In order to evaluate stress/strain simply and suitably under non-proportional loading, Itoh and Sakane have proposed a method called as IS-method and a strain parameter for life evaluation under non-proportional loading  NP . In the method, 6-components of stress/strain are converted to an equivalent stress/strain indicating the amplitude and the direction of principal stress/strain as a function of time as well as an intensity of loading non- proportionality f NP . Based on IS-method, the authors also have developed a tool which enables to analyze multiaxial stress/strain condition with the non- proportionality of loading history and evaluate failure life under non- proportional multiaxial loading. The tool indicates the analyzed results on monitor and users can understand visually not only variation of the stress/strain conditions but also non-proportionality during the cycle, which helps the design of material strength. K EYWORDS . Multiaxial fatigue; Life evaluation; Non-proportional loading; Analysis tool; Cycle counting; Additional hardening. Citation: Morishita, T., Ogawa, F., Itoh, T., Evaluation and visualization of multiaxial fatigue behavior under random non- proportional loading condition, Frattura ed Integrità Strutturale, 41 (2017) 45-53. Received: 28.02.2017 Accepted: 15.04.2017 Published: 01.07.2017 Copyright: © 2017 This is an open access article under the terms of the CC-BY 4.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.