With increasing demands for cost-cutting and global awareness of sustainability, shrink-wrapped tray-based unit loads have become more common recently. This exposes the primary package to external loads, such as pre-tension of shrink wraps, tightness, pattern and number of revs of stretch films, stacking load, side compression load, incidental side impact load from transportation, etc. In addition to evaluating unit load stability and performance, computer simulation can go a step further to assess the potential primary package damage that could be caused by the exposed external loads. The simulation detects any potential issues of the primary package at an early stage of the development process, before physical samples are available, with commensurate reductions in risk, cost, and speed to market.