Comparative analysis of the mechanical properties of a composite material reinforced with carbon fibers and the polymer matrix of epoxy resin

ABSTRACT In recent years composite materials have been developed for different applications in engineering areas. This paper first presents the tensile properties of a polymer, in this case an epoxy resin, to be used as the matrix of a fiber reinforced composite material. A study of the mechanical properties is presented, which was carried out by performing tensile tests under the regime of ASTM D638; five resin specimens were manufactured in which a suitable molding process was performed to optimize specimens type I. The objective was to determine the properties of the thermoset matrix to be reinforced with carbon fiber to improve the composite properties. Subsequently, mechanical properties of the composite reinforced with carbon 3k fibers, are analyzed. For proper analysis ten specimens with an orientation [0/+45/-45]s were made; five tensile tests were conducted in composite specimens based on ASTM standard D3039. The specimens manufacturing process followed the VACCUM BAG WET LAY-U method, under normal air. It is found that epoxy resin specimens generate bubbles by mixing and curing in air. These bubbles, working as stress concentrators, weaken the material tensile strength as compared to the mechanical response of the composite material, which certainly shows better performance due to reinforcing carbon fibers and the manufacturing process in vacuum.