Compression testing to simulate real-world stresses

Unit load testing of boxes reported in the literature typically uses empty boxes to explore the impact and interactions among box configurations, pallet support and other environmental parameters. However, this approach leads to failure in the weakest box in the unitized structure, while in the field, failure almost always occurs in the bottom box, which may or may not be the weakest. We find in this paper that mathematically, numerically and experimentally, forcing box failure to the bottom results in higher test values. While this occurs naturally for boxes in use in the field, it is an interaction which to date has been overlooked by researchers examining box performance in the lab. The impact on box estimation can be on the order of 5% or more, which can be as significant as some of the environmental factors we are working to quantify, and which can have significant cost implications. To improve the assessment used in the industry to account for the impact of a box's 'in use environment' on its performance, we need further testing on configurations where the boxes are loaded.