Evaluating the Behavior of Foamed Plastic Cushioning Materials.

The well-known method of testing cushioning materials using a drop box has been modified so that guided drops can be performed. At the moment of impact the filled metal box including the inserted load mass of solid steel experienced high accelerations (2000 to 3000 g//n), and the response of the test load ranges from 40 to 100 g//n. Tests on eight representative cushioning materials made of expanded polystyrene and the analysis of different existing curves for polyethylene, polyurethane, and air show that the common dynamic cushioning curve is generally applicable to package cushioning materials. This curve can be mathematically described and normalized, so that all imaginable cushioning diagrams result in one set of universal curves. Each curve and thus the behavior of each cushioning material is represented by only three characteristic values.