The flexural behavior of woven prepreg thermoplastic composites

Studies on the flexural damage behaviors of satin and plain continuous-fibe r-impregnated thermoplastic (COFIT) prepreg woven composites were carried o ut. Their weaving characteristics such as float length, interlace region, e tc., which are believed to affect composite properties, were determined. It was found that the satin weave exhibits better flexural properties such as flexural strength and modulus than the plain weave system, with a more obv ious trend in the 3-ply laminate system. The presence of hole damage signif icantly influences the damage resistance of the woven system. Both woven sy stems show a reduction in flexural properties with increasing hole size. In the 3-ply system, due to the greater thickness of the laminate, it was fou nd that the weaving characteristics influence the resin flow and subsequent ly influence the wetting between the laminates and also affect the composit e properties. From the SEM photographs, it was found that the satin weave e xhibits better wetting at the interply region, resulting in better flexural properties than the plain weave. In contrast, the plain weave exhibits deb onding failure at the interply region, which i s obviously observed at the interlace area. This situation might be due to insufficient molding conditi ons such as molding temperature, time, or pressure. It is obvious therefore that different woven patterns require different molding conditions to obta in optimum properties.