Axial compressive behavior and energy absorption of syntactic foam-filled GFRP tubes with lattice frame reinforcement

A kind of innovative foam-filled glass fiber-reinforced polymer (GFRP) tube with lattice frame reinforcement was proposed for improving energy absorption capacity. The crushing experimental results revealed that lattice frame reinforcement contributed to increasing compressive strength and energy absorption, by-33 and 90%, respectively, for syntactic foam-filled GFRP tubes and their plateau stress almost increased to peak strength. Decreasing distances between transverse or vertical bars resulted in increasing energy absorption in composite columns with GFRP shells. The effects of lattice frames on the mechanical behaviors of composite columns without GFRP shells was less significant compared to columns with shells. Under the same content in foam cores, the energy absorption ability of syntactic foam-filled GFRP tubes with lattice frame reinforcement was much higher than that of specimens reinforced by MWCNTs. In addition, an analytical model considering the local buckling of lattice frames was proposed to predict the ultimate crushing load of composite columns with rein-forcement. The analytical solutions agreed well with experimental results. This study provided a promising approach for designing a lightweight composite column with a high capacity for energy absorption, which could be used as an energy absorption member in engineering structures.