Compressive Behavior of GFRP Gradient‐Angle Filament Wound Pultruded Circular Columns

A novel glass fiber reinforced plastic (GFRP) gradient‐angle filament wound pultruded circular column (GAWP) was proposed in this study. Specimens with two parameters including the thickness of the filament‐wound face sheets and the number of sequential angular steps were tested to investigate the compressive behavior and failure modes of GAWP. The results revealed that all the composite specimens failed due to the compressive damage of pultruded tubes followed by the crush of winding filaments, showing an obvious progressive failure process. Pultruded tubes exhibited great axial stiffness, and the application of filament‐wound reinforcements resulted in sufficient utilization of the material's strength. Great pseudo‐ductility was also found in gradient‐angle filament wound structures, with further improvement achieved through increased sequential angular steps. Increasing the thickness of the winding face sheets delayed the initial damage but reduced the ductile coefficient. By introducing three‐dimensional elasticity theory, an analytical model was proposed for evaluating the stress–strain relationship of the specimens, and the results were consistent with the test data.