Influence of Textile Reinforcement on Bending Properties and Impact Strength of SMC-components

Abstract

In Europe, Sheet Molding Compound (SMC) has high market relevance in the field of glass fiber reinforced polymer composites with a market share of almost 20% in terms of mass. The material has a thermal expansion coefficient similar to steel and special grades show Class-A surface quality being thereby an appreciated material in the automotive industry. The mechanical properties of SMC components and thus its implementation in new application fields are mainly limited by the type of fiber and fiber length. The project “Preform-SMC” analyzed the combination of the standard SMC process (chopped long fibers) and the preform technology (textiles) in order to improve the overall performance of components. The studies revealed that the quality of the impregnation of the preform material is mainly determined by the density and thus the filler content of the SMC semi-finished product and the layer structure of the reinforcing fibers. Locally implemented reinforcing textiles improve, by implementing endless fibers among load paths, the mechanical properties. Depending on the fiber type and the layer structure e.g. impact strength and absorbed energy could at least be doubled.