1. Ph.D. Candidate, Dept. of Geotechnical Engineering, College of Civil Engineering, Tongji Univ., Shanghai 200092, China.
2. Associate Professor, Dept. of Engineering Mechanics, Hohai Univ., Nanjing, Jiangsu 210098, China (corresponding author).
3. Branch Head, Structures Division, Naval Air Systems Command, Patuxent River, MD 20670.
4. Distinguished Professor, Center for Aerospace Research and Education, Univ. of California, Irvine, CA 92697.