Study of mixtures of different fibers in sheet molding compound (SMC)

The automotive industry requires parts with high strength and low weight, and if the application requires it, surface quality. These requirements have led to investigate the use of carbon fibers as a reinforcement alternative to the widely used glass fibers. Our previous studies compared the performance of glass and carbon fibers in unsaturated polyester based sheet molding compounds (SMC) for non-structural applications. These showed that there are compromises between the performance of physical properties, cost (incurred by adding the more expensive carbon fibers), and consistency (i.e. variability). In this work, we investigated the effect on physical properties of SMC structural parts when there is a mixture of carbon and glass fibers. Special considerations in the analysis and the implementation of these experiments are discussed.