C-scan

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.

Inspection methods that assess the condition or internal quality of a material or component without damaging it, including ultrasonic, radiographic, thermographic, dye penetrant and acoustic emission techniques. It is essential for finding hidden defects such as delaminations, voids and disbonds in safety-critical structures.

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.

Determination of the proportion of trapped air or volatiles within a cured laminate, typically by density comparison, matrix digestion or burn-off methods, or by image analysis of polished sections. Excess void content degrades interlaminar shear and fatigue performance, so limits are often specified for structural laminates.