Tricot stitched carbon fiber reinforced polymer composite laminates manufactured by resin transfer molding process: C-scan and flexural analysis

NC2 (R) tricot stitched carbon preform has been tested to evaluate its potential application in aircraft structures. It is one in a range of stitched fabric group, specially developed by Hexcel Composites, designed to be processed with a RTM6 monocomponent resin. This article aims to evaluate the tricot stitched fabric behavior towards resin flow front in resin transfer molding process, its mechanical performance in bending test, and its structure during C-scan non-destructive inspection. Flexural performance of the laminates and the scatter of the results corresponded well with C-scan ultrasonic maps, where resin pockets near the stitches were distinguished. The fracture area visualization, via photography and scanning electron microscopy techniques, aided to find a few flaws between the stitch yarns, which conducted to a larger scatter of the flexural rupture strength results.