1. Department of Aerospace & Mechanical Engineering, Saint Louis University, Saint Louis, MO 63103 e-mail:
2. Department of Aerospace & Mechanical Engineering, Saint Louis University, Saint Louis, MO 63103
3. Department of Industrial and Manufacturing Systems Engineering, Kansas State University, Manhattan, KS 66506
4. School of Mechanical Engineering, Shangdong University, Jinan 250061, Shandong, China