Deceleration behavior is one of the most important properties for protective materials. In general, cellular materials such as foams are efficiently used as protective materials. Upon impacted, cellular microstructures show local deformations in the impacted walls while progressive deformations prevail over the materials as the impact energy spreads over the structures. In the most of the cellular materials, buckling of the cell walls is quite common at the first contact. In addition to this deformation mode, compression is also seen in the microstructures. Air filling in the cells provides an efficient energy absorbing mechanism for the cellular materials. In this work, two cellular materials were investigated under an impact system. The first one was a natural cellular material namely cork. On the other hand, the other one was a synthetic material, polyurethane foam. The materials were impacted by a free falling mass and the deceleration of the falling mass was measured by an accelerometer. From the results, specimens show a sudden peak at the impact time. The level of peaks is 56 g and 22 g for the cork panel and the polyurethane foam respectively. It is obvious that impact on the cork panel results in a heavy shock loading on the impacting object that is more than two-fold in comparison to the polyurethane foam.
Anahtar Kelimeler: Deceleration, cork, foam
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