The influence of manufacturing on the buckling performance of thin-walled, channel-section CFRP profiles—An experimental and numerical study

The aim of this study is to investigate the influence of manufacturing on the buckling and post-buckling behaviour of thin-walled, columns made from CFRP. Static compression was performed on channel-section profiles with dimensions equal to 80 mm × 38 mm × 240 mm (web × flange × length of profile) composed of an eight-layered symmetric laminate [45/−45/45/−45] and a thickness of 0.92 mm. The samples were manufactured by two distinct methods: 1) conventional lamination of a channel, and 2) by manufacturing a square cross-section and cutting it into two channels. Buckling tests showed that the second method is 2.5 times more material efficient and provides 18 % higher buckling resistance. Moreover, three finite element models were implemented—a​ model that did not include any prestress (residual stresses), and simulations of the channel and square cross sections where residual stresses were included. The conventional channels matched the numerical results of the model which did not include any prestress (nominal error of 1.8%). Whereas the buckling response of the square cross section samples were substantially influenced by the residual stresses (18.1% increase in buckling load). These results have significant implications for the design/production of CFRP channels with enhanced buckling performance.