Discontinuous fiber reinforced polymers hybrids (DicoFRP), such as sheet molding compounds (SMC) show a lot of positive aspects like great process capability, low costs and good specific mechanical properties. As a result, the SMC material systems meets both, lightweight and mass production criteria.
The microstructural architecture significantly affects the macroscopic mechanical properties of hybrid material systems. Therefore, characterization methods for analyzing the microstructure in detail are essential for characterizing and predicting the DicoFRP behavior on the macroscale. Volumetric images acquired by computed tomography (CT) systems and image processing tools allow a three-dimensional characterization of composite microstructures in a non-destructive way. Though, the limits of X-ray cone beam CT systems due to the conflict between scanned specimen volume and resulting image resolution have to be considered. In order to identify all individual fibers, volumetric images with sufficient high resolution are necessary and thus, only small specimen volumes can be analyzed. However, due to the SMC manufacturing process fibers are arranged as mesoscopic bundles within the final SMC components. To overcome the cone beam CT related conflict between scanned volume and resulting voxel size, this contribution presents an approach to characterize the microstructure based on fiber bundles instead of individual fibers.
In cooperation with the research areas design and technology of the International Research Training Group ”Integrated engineering of continuous-discontinuous long fiber reinforced polymer structures” (GRK2078), the microstructure within generic SMC components are characterized. Especially, the microstructures of weld lines are in the focus of the investigation.