1. Department of Mechanics and Engineering Science, Ningbo University, Ningbo 315211, Zhejiang, P. R. China
2. Key Laboratory of Impact and Safety Engineering, Ministry of Education, Ningbo University, Ningbo 315211, Zhejiang, P. R. China
3. Key Laboratory of E&M (Zhejiang University of Technology), Ministry of Education and Zhejiang Province, Hangzhou 310014, P. R. China