Abstract
A need for light-weighting in the automotive industry is leading to more widespread adoption of composite materials. The high cost of these materials, however, is leading to a search for lower cost solutions. Carbon fibre-reinforced sheet moulding compound (C-SMC) is proposed as a possible cost-effective solution but has several barriers to use; namely warpage of components, and high variability of mechanical properties. This thesis investigated possible factors affecting the distortion of components and found that the distortion, measured by a laser scanner on a ROMER arm, was related to the orientation distribution of the reinforcement affected by the flow, characterised by X-ray computed tomography. It was found that use of cooling jigs could control this warpage to produce in-tolerance components. These findings have already been implemented by the sponsor company to enable use of this material in multiple products. The effects of coupon width, thickness, and mould coverage on apparent tensile strength and Young’s modulus were investigated. This found that strength increases when the coupon width reaches twice the length of the reinforcement. The strength was found to increase with thickness according to a logarithmic relationship, with non-significant differences occurring after the thickness had reached 4 mm thickness. The strength was found to decrease with increasing mould coverage for the mould coverages tested. The modulus was found to not correlate to coupon width, although there was a decrease in variation at 50 mm width. Similarly, the Young’s modulus was not found to change with increasing thickness, but the variance did decrease. The Young’s modulus increased with decreasing mould coverage. This allowed definition of the geometry of a tensile test coupon to increase the confidence in the determined mechanical properties for future test programmes.