Delamination growth

Separation of the plies within a laminate, caused by impact, manufacturing defects, fatigue or moisture ingress. Because it can spread unseen beneath an undamaged surface and sharply reduces compressive strength, delamination is a primary target of non-destructive inspection.

A material's resistance to the propagation of a crack from an existing flaw. It underpins damage-tolerant design, and in laminates the related interlaminar fracture toughness describes resistance to delamination growth.

Progressive, localised damage caused by repeated or fluctuating loads at stresses below a material's static strength. Fatigue governs the life of components such as wind turbine blades, hulls and airframes, and typically initiates at stress concentrations.

The shear strength between the plies of a laminate, usually measured with a short beam shear test such as ISO 14130 or ASTM D2344. Low ILSS indicates poor fibre-to-matrix bonding or laminate quality, and correlates with susceptibility to delamination.