1. School of Statistics and Mathematics, Inner Mongolia University of Finance and Economics, Hohhot, P. R. China
2. School of Materials Science and Engineering, Inner Mongolia University of Technology, Hohhot, P. R. China
3. College of Mechanical Engineering, Beijing Information Science and Technology University, Beijing, P. R. China
4. Beijing Key Laboratory of Nonlinear Vibrations and Strength of Mechanical Structures, College of Mechanical Engineering, Beijing University of Technology, Beijing, P. R. China
5. Department of Mechanics, Inner Mongolia University of Technology, Hohhot, P. R. China