FAA Aviation Mechanic General (AMG)Materials, Hardware and ProcessesMedium
A mechanic is inspecting a composite panel that has been exposed to moisture and freezing temperatures. Which type of damage is characterized by the separation of layers within the laminate, often caused by the expansion of trapped moisture during freezing?
- AFiber breakage
- BDelamination
- CDisbonding
- DMatrix cracking
Show answer & explanationAnswer & explanation
Correct answer: B. Delamination
Delamination is the separation of plies or layers within a composite laminate, often caused by factors like impact, fatigue, or the expansion of trapped moisture during freeze-thaw cycles.
Why the other options are wrong
- A. Fiber breakage refers to the individual fibers breaking, which can contribute to other damage but is not the layer separation itself.
- C. Disbonding refers to the separation between a composite skin and a core material (e.g., honeycomb), or between an adhesive joint, not internal ply separation.
- D. Matrix cracking is cracks within the resin matrix, not necessarily separation between layers.
Composite Delamination
A common type of damage in composite materials where adjacent layers (plies) separate from each other, often initiated by impact, fatigue, or the expansion of trapped moisture.
- Reduces structural integrity and load-carrying capability.
- Can be caused by moisture ingress and subsequent freeze-thaw cycles.
- Often detected by tap testing, ultrasonic inspection, or thermography.
Memory trick: Delamination splits the layers, like ice in a crack.