Delamination

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.

A separation at a bonded interface, such as within an adhesive joint or between the skin and core of a sandwich panel. Disbonds may originate in manufacture or grow in service, and are detected by tap testing or ultrasonic inspection.

The proportion of a cured laminate's volume occupied by trapped air or volatiles rather than fibre or resin. Elevated void content degrades interlaminar shear strength and fatigue performance, so it is controlled through debulking, vacuum and cure pressure and checked by testing or non-destructive inspection.

A non-destructive method that sends high-frequency sound pulses into a material and analyses the reflected or transmitted signals to detect internal flaws and measure thickness. In composites it is the principal technique for finding delaminations, voids and disbonds, applied by pulse-echo or through-transmission scanning.