Turning a grooved foam core changed the bending resistance of composite panels in peer-reviewed laboratory tests. Panels loaded from the grooved side carried more load before failure than the reversed arrangement. Resin filling the grooves formed internal ribs, and computer simulations matched the principal failure pattern seen in a selected experimental configuration.
The same type of foam core behaved differently depending on which face sat beneath the applied load. With the grooved face uppermost, the panels’ failure load was 24–38 per cent higher than with that face reversed. The apparent ultimate shear stress calculated for the core also increased. Epoxy entering the grooves during manufacture left resin ribs inside the completed structure.[1]
Researchers tested panels with a 10 mm PVC foam core between composite skins made with carbon or glass fibres. The carbon-faced configuration resisted bending most strongly among those examined. Failure began with localized wrinkling under compression in the upper skin and developed into crushing beneath the loading points. The grooved arrangement changed resistance near this loaded surface.[1]
The experimental programme covered tension, compression and bending. It included 15 tensile specimens, 27 compression specimens and 72 bending specimens, allowing the team to examine both the constituent materials and the assembled panels. The peer-reviewed work appeared in Scientific Reports.[1]
A three-dimensional simulation represented the resin-filled grooves and the interface between skin and core. For the selected carbon-faced reference under three-point bending, its peak load differed from the experiment by 2.6 per cent and initial stiffness by 6 per cent. Predicted damage concentrated in the upper skin where the laboratory panel had failed.[1]
