Influence of out-of-autoclave and autoclave manufacturing processes on mechanical properties of glass fiber-reinforced epoxy composite

In this study, an optimum process parameter space is proposed by comparing autoclave, oven curing and vacuum infusion process of manufacturing of GFRP composites. The process parameters, such as the degassing time of resin-hardener mix, single or double vacuum bagging (DVB), fiber volume fraction and condition of the vacuum pump (VP) were considered. The novelty of the study shows that a VP Off and 5 min degassing condition exhibited 27%, 18% and 27% increase in tensile modulus, tensile strength and interlaminar shear strength as compared to the other methods. The normalized tensile strength, on the other hand, was comparable with DVB, oven and autoclave curing. A magnitude of 1.5 MPa of residual stress was measured with the help of x-ray diffraction (XRD). This was verified by a Raman Spectroscopy, which showed a residual strain of 0.2% at a spectral peak of 1186 cm(-1). The proposed methodology would assist the industries in choosing the right combination of process parameters required for a targeted tensile and interlaminar performance.