1. Mechanical Engineering and Mechanics, Drexel Univ., Philadelphia, PA 19104.
2. Assistant Professor, Dept. of Civil, Architectural, and Environmental Engineering, Drexel Univ., Philadelphia, PA 19104.
3. P.C. Chou Endowed Assistant Professor, Director of Theoretical & Applied Mechanics Group, Dept. of Mechanical Engineering and Mechanics, Drexel Univ., 3141 Chestnut St., Philadelphia, PA 19104 (corresponding author).