Buckling Behavior and Failure of Hybrid Fiber-Reinforced Polymer Pultruded Short Columns

This paper addresses the buckling behavior and strength of hybrid pultruded short profiles subjected to uniform compression. Since the design of glass fiber-reinforced polymer (GFRP) pultruded profiles is often governed by deformations and buckling phenomena, the introduction of carbon fibers in GFRP (hybrid) profiles has been proved to increase both strength and stiffness of flexural members. In the context of short compression members (columns), experimental, numerical, and analytical studies were carried out, with particular attention being given to the local buckling. Two series of 660-mm-long I-section profiles (200×100×10 mm) were tested under uniform compression. In order to evaluate the advantages of introducing carbon fiber reinforcement in the flanges, two profile types were tested: bare GFRP profile (reference column) and carbon fiber reinforced polymer (CFRP) strengthened GFRP profile (hybrid column). Shell finite-element (SFE) models were developed and validated, based on experimental data. After that, and in order to predict the critical buckling loads of the tested columns, a study was performed using analytical solutions based on the orthotropic plate theory. Both numerical and analytical results presented a good agreement with experimental data. Results obtained show that the critical load, the ultimate load, and the axial stiffness considerably increase with the introduction of CFRP sheets in the flanges of the GFRP profile.