Experimental investigation of the static behaviour of a corrugated plywood sandwich core

Sandwich panel structures comprising corrugated plywood core bonded between plywood face sheets were manufactured and tested in flatwise compression and bending. Thin 3-ply Radiata pine veneers were soaked in a hot water bath prior to forming in a heated matched die, resulting in a corrugated profile with a 9 mm height and 43 mm period. Sandwich panel specimens were assembled via a simple process of applying an epoxy adhesive along the joints of the corrugated core and plywood face-sheets and holding in position while the epoxy cured. Through-thickness compressive modulus and strength were tested following the method of ASTM C365. As compared to single layer core, double layer core had a similar modulus, but reduced strength due to instability at the joints between the corrugation layers. Bending behaviour of sandwich beams was investigated in both the corrugated core orientations, revealing that the core was stiffer in shear across the corrugations, but also weaker in this orientation, due to face sheet buckling. This work sets the foundation for future research involving the prediction of properties and experimentation with different core configurations.