Failure Modes of Folded Sandwich Panel Roofs

Folded sandwich plate structures make effective light-weight roof structures capable of carrying relatively high loads. Two models were tested. The first had a span of 9.5 ft (2.90 m) and a saw-tooth cross section made up of six 2-ft wide (61 cm) sandwich panels having 0.025-in thick (0.64 mm) aluminum facings and 1-in thick paper honeycomb core. Shear failures (delaminations and bulging of facings) occurred at the ends of the model at a load of 17,750 lb (79,000 n) uniformly distributed along the internal five ridges. The second model had a span of 19 ft (5.80 m) and a cross section similar to the first-model, with panels having styrolite core. The two internal hip ridges buckled at midspan when the model was subjected to 75.4 psf (3620 N/m²) of pressure.