Experimental investigation of open-hole compression strength of carbon epoxy composite material and determination of localized strains using digital image correlation technique

Abstract

Fiber-reinforced composites are widely known for their application to military and commercial aircrafts, in which the weight reduction is required to ensure higher speeds and increased payloads. Carbon fibers, either alone or with the Kevlar 49 fibers, are widely used as the main materials in many aero plane wing, fuselage, and empennage components. Composite materials have many applications in different industries owing to their very different properties from those of metals and polymers. While drilling the carbon/epoxy composites, the cut surface quality highly depends on the drilling parameters set during drilling which further affects the strength of the hole during extension/compression loading. In this study, Carbon Fiber Epoxy Composite (CFEC) material was drilled using the standard carbide drill bit, and Open Hole Compression (OHC) tests were carried out on the Universal Testing Machine. In addition, Digital Image Correlation (DIC) technique was employed to find out the strain distribution around the hole during compression loading. Based on the experimental method and DIC, the maximum strength of the carbon epoxy composite was achieved by drilling at 1600-2400 mm/min in the presence of notch. It was also observed that failure of the structure was dependent on the drilling feed rate and the optimized drilling range was 1600-2400 mm/min.