Skin-core debond

Separation of the plies within a laminate, caused by impact, manufacturing defects, fatigue or moisture ingress. Because it can spread unseen beneath an undamaged surface and sharply reduces compressive strength, delamination is a primary target of non-destructive inspection.

Inspection methods that assess the condition or internal quality of a material or component without damaging it, including ultrasonic, radiographic, thermographic, dye penetrant and acoustic emission techniques. It is essential for finding hidden defects such as delaminations, voids and disbonds in safety-critical structures.

The shear loading carried by the core of a sandwich panel as it bends, transferring load between the two face sheets. Core shear strength and shear modulus are primary selection properties for core materials, and core shear failure is a common design-limiting mode in sandwich structures.

The thin, stiff outer layer bonded to each side of a sandwich core, typically a fibre-reinforced laminate or a metal sheet. Face sheets carry the in-plane tensile and compressive loads generated when the panel bends, while the core separates them and carries the shear.