1. Doctoral Candidate, Dept. of Mechanical Engineering, South West Jiaotong Univ., Chengdu 610031, China.
2. Professor, Dept. of Mechanical Engineering, South West Jiaotong Univ., Chengdu 610031, China.
3. Associate Professor, Dept. of Mechanical Engineering, South West Jiaotong Univ., Chengdu 610031, China.
4. Professor, Dept. of Mechanical, Aerospace, and Civil Engineering, Brunel Univ. London, Uxbridge UB8 3PH; and National Structural Integrity Research Centre, Granta Park, Cambridge CB21 6AL, U.K. (corresponding author).