1. Associate Professor Nonlinear Vibrations and Energy Harvesting Lab (NOVEHL), Department of Mechanical Engineering, Clemson University, Clemson, SC 29634 e-mail:
2. Department of Mechanical Engineering, Clemson University, Clemson, SC 29634 e-mail:
3. Assistant Professor G. W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA 30332–0405 e-mail:
4. Professor Department of Mechanical Engineering, The University of Akron, Akron, OH 44325–3903 e-mail: