Plain English Meaning

A composite part is built up from many thin layers stuck together. A delamination is when those layers start to separate, like pages coming unglued in a book. The part may still look fine on the surface but is no longer as strong as it should be.

Full Definition

Separations between the bonded layers of a composite structure, where the layers of fiber and resin that should be fused together come apart. Delaminations weaken the structure and may not be visible from the outside, so they often require tap testing, ultrasonic inspection, or other non-destructive methods to detect.

Context Anchor

Seen in discussions of composite aircraft construction, inspection, impact damage, and repair limits.

Derivation

From Latin 'de-' meaning 'apart' or 'away from,' and 'lamina' meaning 'thin layer or sheet.' Literally 'an un-layering.' Knowing this makes the meaning intuitive: the layers come apart.