Structural Performance of the Improved CFRP-Steel Tube Composite Truss: A Finite Element Analysis

The improved CFRP-circular steel tube composite truss was proposed to enhance the connection strength of the steel tube and the anchoring strength of the CFRP sheet by setting it with a thick-walled steel tube at both ends of the members. To investigate the mechanical performance of these novel composite members when used in truss structures, parametric finite element analysis was conducted on the mechanical performance of the composite truss in this paper. The typical stress state of the steel truss, the conventional composite truss, and the improved composite truss were compared in detail. The effect of the number of CFRP layers and the layout of the improved CFRP-steel tube composite member (CFRP-STCM) on the mechanical performance of the composite truss is also incorporated. The analysis results reveal that the thick-walled steel tube can effectively decrease the interfacial stress and hence increase the load-bearing capacity of the composite truss. The load-bearing capacity of the improved composite truss was 53.4 and 28.1% higher than that of the steel truss and the corresponding conventional composite truss, respectively, and has better ductility. The number of CFRP layers and the arrangement of the improved composite members had a great effect on the load-bearing capacity and ductility of the truss. Replacing the weakest compressive braces of the steel truss with the improved composite member can significantly improve the load-bearing capacity and ductility of the truss. The feasibility of the improved composite truss was validated by the refined parametric finite element analysis.