DESIGN AND DEVELOPMENT OF THREE-DIMENSIONAL MULTILAYER WOVEN PREFORMS FOR COMPOSITES
Peter So Wah Tung
At present, the majority of high performance composites are in the form of laminates which are fabricated from multiple layers of uniaxial tape or biaxially woven fabrics. The process of fabricating these laminates is labor intensive and their inherent design features result in poor interlaminar mechanical properties.
The primary purpose of this research was to design and develop three-dimensional multilayer woven fabrics on modified weaving machines with the anticipation that composites fabricated from these structures will have improved interlaminar properties. Five-layer woven fabric preforms wee produced with three different weave constructions.
The three fabric preforms were processed into prepregs, cured into composites and then tested for tensile and flexural properties using ASTM Standards.
It has been shown in this research that conventional weaving machines can be modified to produce multilayer woven fabrics for use in composite structures.
In general, the test results on the composites were inconclusive. This could be attributed to problems and inconsistencies in one or more of the following: variations in yarn densities, prepreg processing, composite fabrication, curing or physical testing. C-scan measurements on the composites also showed numerous voids.