1. Postdoctoral Assoc., Dept. of Mech. Engrg. and Ctr. for Comp.-Aided Des., Univ. of Iowa, Iowa City, IA 52242-1527.
2. Assoc. Prof., Dept. of Mech. Engrg. and Ctr. for Comp.-Aided Des., Univ. of Iowa, Iowa City, IA 52242-1527 (corresponding author). E-mail: jschen@icaen.uiowa.edu
3. Proj. Engr., Peoria Proving Ground, Caterpillar, Inc., Peoria, IL 61656-1895.
4. Sr. Proj. Engr., Peoria Proving Ground, Catepillar, Inc., Peoria, IL 61656-1895.