Composites can be manufactured using either resin transfer ...

CHAPTER 3
FABRICATION OF COMPOSITE PANEL
Composite materials can be manufactured using resin transfer molding (RTM), vacuum
assisted resin transfer molding (VARTM), compression molding, and the filament winding
method. In this study, a VARTM process is used to fabricate CFRP composite panels.
Composite materials manufactured using the VARTM process have the advantages of
improved quality, improved fiber wet-out, reduced void content, and reduced tooling costs
compared to RTM [56] and hand layup.
Surface treated and sized unidirectional carbon fibers, IM7, were used for fabricating
composite panels. IM7 is a high tensile and shear strength fiber. The VARTM process is
comprised of surface mold preparation, fiber layup, vacuum creation, resin preparation, resin
infusion and curing. In this thesis, fabrication of a panel with orientation [06/904/06]T
containing a simulated embedded crack is described. The remaining panels required for
testing were similarly fabricated. The carbon fiber fabric was cut into 304.8 mm × 304.8 mm
squares that form the 16 plies. Four plies, oriented in the 90º direction, were cut in the
middle, parallel to the fiber direction to simulate the transverse crack.
The surface mold was prepared by spraying a release agent, previously cleaned with
acetone, to aid in fabric release. In addition to the release agent, a release film was placed on
the mold before laying up the fabric. Six plies were laid in the 0º direction, followed by four
plies with the pre-fabricated cut in the 90º direction. A thin parafilm was placed along the
crack to avoid fiber bonding during fabrication. The remaining six plies were placed on top in
the 0º direction. A second release film and distribution mesh was placed above the fabric. A
distribution mesh promotes uniform distribution of resin and controls resin flow. The entire
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