1. Department of Mechanical Engineering, Virginia Tech, Blacksburg, Virginia 24061, United States
2. Department of Mechanical Engineering, University of California Santa Barbara, Santa Barbara, California 93106, United States
3. Department of Biomedical Engineering and Mechanics, Virginia Tech, Blacksburg, Virginia 24061, United States
4. Physique et Mécanique des Milieux Hétérogènes, UMR 7636 du CNRS, ESPCI, 75005 Paris, France