Computed Tomography Investigations of GFRP Omega Profiles manufactured by Vacuum Assisted Resin Transfer MouldingPart of:
The use of fiber reinforced plastics (FRP) is increasing nowadays because of the ensured weight reduction and good properties (mechanical, chemical, electrical) of the produced structures which is crucial in many applications such as aircraft industry, offshore industry, automotive field and wind energy field. In the last decades, the most commonly used fibers for the production of composites materials are glass fibers due to their high performance / low production costs ratio compared to other fiber types.
In this work, omega profiles made of glass fibers reinforced plastic (GFRP) are manufactured by the vacuum assisted resin transfer moulding process, which can be used for internal fittings in automotive industry. By this procedure, a preform out of biaxial nonwoven-scrim is placed into the tool cavity. After closing the rigid steel mold and subsequent injection, curing of a very high reactive epoxy resin takes place. This technology allows a fast manufacturing of FRP components with very good laminate and surface quality. The quality of the produced parts is evaluated by the non-destructive testing technique computed tomography (CT) where the porosity inside the parts and the distribution of the wall thickness is examined. This can serve to optimize the processing method based on the requirements of the automotive applications.
In the next step, quasi-static three point bending tests are carried out on the produced profiles in order to evaluate the mechanical behavior of the produced GFRP considering the different production effects. This should provide a correlation of the mechanical properties with the production level. In this context, CT investigations are realized on the loaded parts with the purpose to identify the responsible damage mechanisms.
The first CT results developed on the non-damaged parts show a porosity varying between 0.82% and 1.24%, considering 4 manufactured components. The largest pores are detected at the corner of the flank. Furthermore, through the measurements of the wall thickness it is to notice that the wall thickness is not the same along the GFRP part and at the flank, in special, lower than the set point. This can be caused by the shrinkage of the used epoxy resin.