Crimp

A family of reinforcements in which straight, uncrimped layers of fibre are held together by stitching or bonding rather than by weaving. Avoiding crimp improves stiffness, strength and fatigue performance compared with equivalent woven fabrics, and the format suits automated handling and the infusion of large parts.

A heavy, coarse fabric woven directly from untwisted glass rovings, usually in a plain weave. It builds laminate thickness and directional strength quickly and is traditionally alternated with chopped strand mat in marine and industrial GRP laminates.

The ability of a reinforcement fabric or prepreg to conform to a curved or double-curved mould surface without wrinkling or bridging. Weave style, fibre type and binder all affect drape, which is assessed when selecting materials for complex geometry.

Reinforcement in which virtually all fibres run in a single direction, supplied as dry tape, lightly stitched or bound fabric, or prepreg. Unidirectional plies give the highest stiffness and strength along the fibre direction but need supporting plies in other orientations.