1. Ph.D. Student, College of Mechanics and Materials, Hohai Univ., 8 Focheng Xilu, Nanjing 211100, PR China.
2. Professor, College of Mechanics and Materials, Hohai Univ., 8 Focheng Xilu, Nanjing 211100, PR China (corresponding author).
3. Professor, College of Mechanics and Materials, Hohai Univ., 8 Focheng Xilu, Nanjing 211100, PR China.