Effect of Humidity on Corrugated Fiberboard Bidirectional Property

Abstract

The effect of overhanging on corrugated box compression strength is well known. However, the combined effect of overhang and humidity is usually based on the superposition method, where humidity and overhang effects are applied separately. In this study, 9x9x9” single-wall corrugated boxes were used. They were tested with a relative humidity of 50%, 65%, and 80% together with an overhang of 1 – 4 inches. As expected, the humidity reduces the compression strength of the box. As the overhang increases toward the midpoint of the box’s dimension, the rate of strength reduction becomes slower. This is because the box corners carry a lot more load than the wall. Estimation of strength as a percentage of the strength of zero overhang for 9x9x9” boxes was developed as: % Of Zero Overhang Strength = 0.0233x2 - 1.8581x + 99.089 where x = Overhang as % of box dimension. The equation can also be presented in term of strength loss as: % Loss from Zero Overhang Strength = -0.0233x2 + 1.8581x + 0.9105 Keywords Overhang; Corrugated Boxes; Compression Strength; Humidity Effect