1. Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI 48105 e-mail:
2. Department of Mechanical and Aerospace Engineering, The Ohio State University, Columbus, OH 43235 e-mail:
3. U.S. Army Tank Automotive Research, Development, and Engineering Center (TARDEC), 6501 E. 11 Mile Road, Warren, MI 48397-5000 e-mail: