1. Department of Civil Engineering and Engineering Science Programme, National University of Singapore, Singapore 117576, Singapore
2. School of Mechanical Engineering and Automation, Fuzhou University, 350108, P. R. China; School of Engineering, University of Western Sydney, Penrith South DC, NSW 1797, Australia
3. School of Engineering, University of Western Sydney, Penrith South DC, NSW 1797, Australia
4. Department of Mechanical Engineering, Texas A&M University, College Station, TX 777843-3123