Fibre orientation and rheological behaviour in compression moulding

Abstract: Compression moulding is a common manufacturing process for composite materials. In order to better predict the processing and performance of components, simulation tools are becoming more important. In this thesis the behaviour of the compression moulding raw material has been studied to provide a platform for better simulations. In paper I, anisotropic rheological properties of GMT are investigated. The reason for this problem is that the fibres are not randomly oriented. The anisotropic behaviour as well as comparisons of different raw materials are shown in the paper. In paper II the measurement of the fibre orientation distribution is studied. The necessary sample size is determined by statistical analysis. The full procedure for fibre orientation measurements including sample preparation and image capturing is described. In paper III the isothermal rheological properties of GMT are studied on industrial relevant sample sizes and closing velocities in a 310 tonnes press. The experimental data have then been compared to existing models for squeeze flow rheology of GMT. Necessary material coefficients have been derived and the validity of the studied models has been determined.