1. Piezoelectric Device Laboratory, School of Mechanical Engineering and Mechanics, Ningbo University, Ningbo, Zhejiang 315211, China
2. School of Mechanical and Electrical Engineering, Ningbo Dahongying University, Ningbo, Zhejiang 315175, China
3. Department of Mechanical and Materials Engineering, the University of Nebraska-Lincoln, Lincoln, NE 68588-0526, USA