Research on the mechanical properties of a glass fiber reinforced polymer-steel combined truss structure.

Pengfei Liu,Fei Li,Qilin Zhao,Jinchun Liu,Haosen Chen

doi:10.1155/2014/309872

Abstract

An assembled plane truss structure used for vehicle loading is designed and manufactured. In the truss, the glass fiber reinforced polymer (GFRP) tube and the steel joint are connected by a new technology featuring a pretightened tooth connection. The detailed description for the rod and node design is introduced in this paper, and a typical truss panel is fabricated. Under natural conditions, the short-term load test and long-term mechanical performance test for one year are performed to analyze its performance and conduct a comparative analysis for a reasonable FEM model. The study shows that the design and fabrication for the node of an assembled truss panel are convenient, safe, and reliable; because of the creep control design of the rods, not only does the short-term structural stiffness meet the design requirement but also the long-term creep deformation tends towards stability. In addition, no significant change is found in the elastic modules, so this structure can be applied in actual engineering. Although the safety factor for the strength of the composite rods is very large, it has a lightweight advantage over the steel truss for the low density of GFRP. In the FEM model, simplifying the node as a hinge connection relatively conforms to the actual status.

Highlights

glass fiber reinforced polymer (GFRP) has excellent performance characteristics, such as lightness, high strength, flexibility in design, good antishock performance, and fatigue and corrosion resistance, as well as good protection and concealment function
The connection efficiency of frequently used connection technologies for a composites-adhesive connection, mechanical connection, and bolt-adhesive connection is not generally high, and there is a significant aging problem for the adhesive connection, which restricts the application of GFRPs in civil engineering as the main load-bearing structure
The pretightened tooth connection joints can be used for unidirectional extension or multidirectional connections of composite members and can be made into singleor double-lug joints between GFRP-steel combined truss panels and spherical joints

Summary

Introduction

GFRP has excellent performance characteristics, such as lightness, high strength, flexibility in design, good antishock performance, and fatigue and corrosion resistance, as well as good protection and concealment function. Lifshitz and Rotem [11] find that, for a unidirectional glass fiber/polyester composite with a fiber volume fraction of 60%, creep failure occurs over 105 min for under 50% of the initial tensile strength at room temperature. Under a stress higher than 50% of the static strength, bending creep failure occurs successively for the samples of 307 glass/polyester composites [12]. The connection efficiency of frequently used connection technologies for a composites-adhesive connection, mechanical connection, and bolt-adhesive connection is not generally high, and there is a significant aging problem for the adhesive connection, which restricts the application of GFRPs in civil engineering as the main load-bearing structure. The truss structure of GFRP is usually used for pedestrian bridge and roof structures that have a lower bearing capacity and a smaller span. The bolted connection is adopted for a GFRP truss roof structure that is 19 m in length and 4 m in width to bear loads of wind and snow

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Conclusion