Void content measurement

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.

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.

The proportion of a composite's volume occupied by fibre, a key measure of laminate quality and the main driver of stiffness and strength in the fibre direction. It is determined by methods such as resin burn-off, acid digestion or image analysis of polished sections.

A two-dimensional plan-view map of a component produced by ultrasonic scanning, in which signal amplitude or time of flight is plotted over the scanned area. It is the standard output of automated composite inspection, showing the size and position of delaminations, voids and inclusions at a glance.