Liu, Yu. M.S.M.E., Purdue University, May 2016. Modifications to Johanson’s Roll Compaction Model for Improved Relative Density Predictions. Major Professor: Carl Wassgren, School of Mechanical Engineering. Johanson’s roll compaction model [J.R. Johanson, A rolling theory for granular solids, ASME Journal of Applied Mechanics E32 (1965) 842–848] is modified to improve its predictions of a compa...