Issue 40

L. Zou et alii, Frattura ed Integrità Strutturale, 40 (2017) 137-148; DOI: 10.3221/IGF-ESIS.40.12 137 S-N curve modeling method of Aluminum alloy welded joints based on the fatigue characteristics domain Li Zou Software Institute, Dalian Jiaotong University, Lvshun 116052, China lizou@djtu.edu.cn Xinhua Yang College of Material Science and Engineering, Dalian Jiaotong University, Dalian, China yangxhdl@foxmail.com Jianrong Tan Department of mechanical engineering and automation, Zhejiang University, Zhejiang, China Yibo Sun College of Material Science and Engineering, Dalian Jiaotong University, Dalian, China A BSTRACT . The scatter degree of the fatigue samples is reduced when the nodal force based structural method is used for steel welded joints, while it is still high for aluminum alloy welded joints. Statistical method and rough set theory is used to fatigue analysis so that fatigue characteristic domains are determined and S-N curves are fitted. Experiment results show that fatigue life of the aluminum alloy welded joints is under the influence of some key factors and the fatigue data with the same characteristics distribute in a relatively independent area. Accordingly, a novel S-N curve modeling method of aluminum alloy welded joints based on the fatigue characteristics domain is proposed. In the proposed method, the nodal force based structural stress method is used for stress calculation and neighborhood rough set theory is used for character extraction to obtain the key factors. Then fatigue characteristics domains are divided and S-N curves are fitted on each fatigue characteristics domain instead of on the whole domain so that a set of S-N curves are obtained. Statistical results show that selection of the S-N curve for the aluminum alloy welded joints according to different fatigue characteristic domain is more accurate. K EYWORDS . Welding; Fatigue; Structural stress; Rough set theory; S-N curve. Citation: Zou., L., Yang, X., Tan, J., Sun, Y., S-N curve modeling method of Aluminum alloy welded joints based on the fatigue characteristics domain, 40 (2017) 137-148. Received: 09.11.2016 Accepted: 10.01.2017 Published: 01.04.2017 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.