Flexural Behavior of Multi-Cavity Composite Beams of Multi-Axial Fiber Reinforced Pultrusion Pipes

This paper investigates the bending performance of multi-axial fiber reinforced pultruded pipes with multi-cavity cross-sectional composite beams. The beams are constructed using glass fiber reinforced polymer (GFRP) wrapped around pultruded pipes, and they are fabricated using the vacuum infusion molding process. Through experimental research and theoretical analysis, the effects of different cross-sectional shapes and the number of cavities on the bending performance of composite beams are explored. Four-point bending tests are conducted to compare the failure modes of the specimens, and detailed analyses of deformation and strain are performed using load–displacement and load-strain curves. The bearing capacity and stiffness of the beams are further investigated. The experimental results show that the composite beams exhibit better bending performance under lateral compression, and an increase in the number of cavities effectively enhances the bending performance.