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.
Plain English
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.
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.
Why Pilots Care
Delaminations reduce structural strength without obvious external signs and can lead to sudden failure under flight loads.
Analogy
Think of plywood or a glued book cover starting to separate into layers. The outside may still look usable, but the bond between the layers is no longer sound.
Intuition Check
Do not assume delaminations are just surface cracks or cosmetic marks. They are separations between layers, and some may be hidden inside the part.
Example Sentence 1
After the hailstorm passed through the ramp, the owner had the composite wing inspected for delaminations before returning the aircraft to service.
Example Sentence 2
Repeated flexing in flight can enlarge existing delaminations in a composite wing spar.