Light-weighting materials for semi-structural applications for automotive

Abstract

Proyecto confidencial (Riunet)

[EN] The growing attention about environmental issues prompted European Union to take action to reduce the emission of pollutant gases; said actions had an impact also on automotive sector. The desired goal is to limit the maximum allowed value for vehicles CO2 emissions to approx. 95g/km, by 2020. Several studies showed that the reduction of weight can decrease the amount of CO2 emitted by vehicles: that is one of the possible (even not the only) way to reach the emission target. Throughout this master’s thesis, low density materials were studied, aimed at reducing the weight of single components as well as the overall weight of the vehicle. The materials investigated in this thesis are bio-composites polypropylene-based reinforced with 30 and 40% wood fibers and 20% hemp fibers, as well as another polypropylene-based reinforced with 24% of glass bubbles. In the case of the wood fiber composite, its behavior in terms of the pigment presence was further analyzed. The properties of these new materials were compared with three standard talc-filled composites, which are already used in various components inside the vehicle, as well as with another talc and glass-filled composite used for air ducts. The mechanical, thermal and physical characteristics of abovementioned materials have been evaluated according to international standards. Several tests were performed to characterize the new composite materials: - mechanical tests showed quite good flexural and impact failure properties at different temperatures, but poor elongation behavior; - thermal tests showed no significant variation of surface properties in comparison with reference materials; - density measurements showed the potential employment of these materials for light-weighting automobile applications. Finally, an overall evaluation of total energy consumption, combined with the total weight savings, showed quite promising results. Therefore, the materials investigated appears to be quite interesting for automotive application.