Mechanical Characteristics of Low-cost Hybrid Fiber Reinforced Polymer

This report deals with the experimental investigation of using large deformable FRP, ± 45° oriented fibers, in concrete-filled fiber tubes (CFFT) under axial cyclic compressive loading. In addition, this report presents finite element modeling (FE) of CFFTs with large rupture strain FRP (LRS-FRP). The LRS-FRP is made with polyethylene naphthalate (PEN) and polyethylene terephthalate (PET) fibers. The PEN and PET fibers are environmentally friendly as they are made from recycled materials (e.g. bottles). They have high ultimate strain (> 5.0%) however their elastic modulus is low. The experimental work consists of two CFFT cylinders have outer three layered FRP tube with fiber oriented at ± 45° and one CFFT cylinder has three hybridlayered FRP [± 45/0]. The investigated cylinders are tested under axial cyclic compressive loading. The FE study investigates six cylinders of PET-FRP and three cylinders of PEN-FRP. One, two and three layers of each type are investigated in this study. The FE investigated cylinders are numerically analyzed under axial monotonic compressive loading using LSDYNA. The experimental results presented in this report indicate that the angle-ply fibers have ability to dissipate high energy and achieve good ductility. The angle-ply fibers are reorienting during loading before reaching the rupture strain without considerable enhancement in the compressive strength. The FE results showed that the thick LRS-FRP achieved much better behavior in strength and ductility than the conventional FRP (glass and carbon). This indicated that the FRP ultimate strain had a great effect on the concrete confinement even if the elastic modulus was low.