Experimental investigations of thin-walled GFRP beams subjected to pure bending

The results of the experimental buckling and postbuckling behaviour analysis of thin-walled, square cross-section tubes subjected to pure bending are presented. The beams under investigation were manufactured from a glass fibre reinforced polymer unidirectional prepreg tape in an autoclaving procedure. The experimental results for six different layups of the eight-layer laminate were considered. In order to collect all necessary data, strain gauges and an ARAMIS Digital Image Correlation (DIC) system produced by the GOM company were employed. The strain gauges measured strains at one point, whereas the DIC system was able to generate maps of displacement fields. On the basis of the data from an Instron universal testing machine, it was possible to determine buckling loads and equilibrium paths in order to compare the results. Moreover, grips designed especially for pure bending tests are presented.