Local anisotropy analysis in injection moulded fibre reinforced polymer composites

The fibre orientation distribution in a material sample extracted from an injection moulded plate, displaying the commonly encountered layered shell-core-shell structure, was analyzed. Starting from a micro tomography reconstruction of the sample, instead of trying to isolate each single fibre and measuring its geometrical properties, we derived the components of a fabric tensor from the evaluation of a global anisotropy parameter, the mean intercept length MIL. This parameter, commonly employed for the analysis of biological and geological structures, proved to be an efficient tool for the analysis of the structure of short fibre reinforced composites. The local variations of the degree of anisotropy (ratio of the maximum and minimum eigenvalues of the fabric tensor) from the shell to the core layers of the injection moulded plate could be captured and information about the local average fibre orientation angle was also obtained.