1. Department of Mechanics, Huazhong University of Science and Technology, 1037 Luoyu Road, Wuhan 430074, China
2. Hubei Key Laboratory of Engineering Structural Analysis and Safety Assessment, Luoyu Road 1037, Wuhan 430074, China
3. Department of Mechanical Engineering and Science, Kyoto University, Nishikyo-ku, Kyoto 615-8540, Japan