If the skins are peeled from the core, a sandwich structure loses its strength and stiffness.
This can occur under
- wave-slamming in fast ferries
- rapid depressurisation of an aircraft
The single cantilever beam (SCB) is used for thick-skinned structures.
The lower skin is loaded forcing a crack along the skin-core interface. The force-displacement (P-δ) curve and crack lengths, a, are recorded The compliance, C, is assumed to follow:
Typical values:
Glass fibre epoxy/balsa 900 J/m2
Carbon fibre/PVC foam 2000 J/m2