Local Failure of Plastic-Foam Core Sandwich Panels

The theoretical and experimental investigation of axially loaded architectural sandwich columns having plastic foam cores was concentrated on establishing analysis formulas for localized modes of instability. The objective was accomplished through the development of face wrinkling theories, which, for the first time, allow the unified analysis of face wrinkling with initial waviness for anti-symmetrical mode shapes. The procedure is based on an improvement in the beam-on-elastic foundation theory coupled with a semi-empirical correlation factor for initial waviness. The significance of this method is that face wrinkling mode of buckling may be determined without need for experimental testing of a similar sandwich to that being designed. Experimental studies revealed face wrinkling as the controlling local failure mechanism. A theoretically sound and statistically supported design guide was presented to provide the structural designer with a rational and manageable method for predicting face wrinkling failure stresses in foam-plastic core architectural sandwich panels.