DescriptionGlass-fibre reinforced polymer matrix composites exhibit superior properties to traditional materials. Thus, they have found a broad variety of applications in modern industry. For process development and quality control sophisticated methods for non-destructive characterisation are needed. X-ray computed tomography (CT) is a powerful radiographic non-destructive-testing method to locate and size volumetric details in three dimensions. The CT image is derived from a large number of systematic observations at different viewing angles, and the final CT image is then reconstructed with the aid of a computer cluster. In the last years µ-CT systems with a matrix detector and a micro-focus tube become more and more popular. The main advantages of these systems are the reasonable high scanning speed and the high resolution. This paper comprises the characterisation of glass-fibre reinforced polymers by µ-CT to measure diameter, length and the three-dimensional orientation of the contained fibres. For this respect µ-CT-measurements with resolutions between 15 µm and 5 µm were done on polymeric samples prepared by injection moulding with different process parameters. Fibre reinforced polybutyleneterephthalat and polypropylene with fibre diameters of about 13 µm were prepared with fibre loadings between 10 and 30 volume percent and injections flows between 5 and 140 cm3/s. For comparison and verification one sample was also studied using synchrotron-CT at the European Synchrotron Radiation Facility (ESRF) in Grenoble with a resolution of 0.7 µm. Additionally, the experimental results were compared to results of the simulation-programme Moldflow. Our investigations lead to the following results. µ-CT is a very powerful method for the characterisation of glass-fibre reinforced polymers. The diameter of glass-fibres can be determined by µ-CT, if the resolution is at least a factor 2 better than the diameter of the glass fibres. Lengths and three-dimensional distribution of glass fibres can be determined by µ-CT even at a limited resolution. For this task a CT-resolution equal to the fibre diameter is sufficient. The experimental CT-results correspond to the simulation results of Moldflow concerning the fibre orientation quite well. However, the strength of the orientation of the fibres is overestimated by Moldflow as compared to the CT-results.
|Period||16 Jun 2008|
|Event title||PPS-24: null|