delaminated

Delaminated is an adjective used to describe a material that has undergone delamination, the separation of its layered structure along interfaces between layers or within a layer. Delamination is a mode of failure that compromises the material’s ability to transfer load between layers and can lead to reduced strength, stiffness, and barrier properties. The term is commonly applied to laminated or composite systems such as fiber-reinforced polymers, plywood, laminated glass, and multi-layer coatings, but it can also describe separating phenomena in other multi-layer assemblies.

Causes of delamination include mechanical impact or fatigue, thermal cycling and thermal expansion mismatch between layers, moisture or chemical attack that weakens interfacial bonds, and manufacturing defects such as poor adhesive distribution or inadequate curing. Aging and environmental exposure can also promote delamination over time. Delamination may occur at the adhesive interface (interfacial debonding) or within a cohesive layer (intra-laminar separation), and it often initiates at points of stress concentration or moisture ingress.

Diagnosis relies on non-destructive evaluation methods and visual inspection. Techniques include ultrasonic testing, infrared thermography, acoustic emission monitoring, and, in some cases, cross-sectional microscopy. Prevention focuses on proper material selection and design to minimize interlaminar stresses, use of tougher or better-matched matrices and adhesives, controlled curing, and moisture protection. Repair strategies range from localized patching or scarf repairs to replacement of affected plies or entire layers, depending on the extent of damage.