Residual stress

The fractional change in a material's dimensions per degree of temperature change. Mismatched expansion between joined materials, for example a composite bonded to aluminium, generates thermal stresses and distortion that must be allowed for in design.

The tendency of a cured composite angle or curved section to close slightly relative to the mould geometry, caused by the difference between in-plane and through-thickness thermal and cure shrinkage. Tooling is often compensated at the design stage to allow for it.

A localised increase in stress around a geometric feature such as a hole, notch, sharp corner or ply drop. Stress concentrations are common initiation sites for fatigue cracks and are managed with generous radii, local reinforcement and careful detailing.