Effect of Fiber Orientation on Nonlinear Behavior of CFRP Composites

Abstract

Fiber orientation is one of the important parameters that affect strength and ductility of FRP-confined concrete columns. A number of studies have been conducted on various fiber orientations and wrap thicknesses, but have not been carried out as a comprehensive study on tensile properties of FRP with various fiber orientations and their effects on confined concrete. This article presents the results of experimental studies about mechanical properties of CFRP composites. In this study, 24 coupons of CFRP composites were prepared and tested in axial tension under displacement control mode. Eight-ply configurations were prepared with fibers oriented at 08, ±458, and 908 from the axial direction and with 1, 2, 3, and 4 plies. It was found that stress-strain behavior basically depended on fiber orientation. The behavior in on-axis orientation was shown to be perfectly linear-elastic with brittle rupture, but in off-axis orientation it was shown to be fully nonlinear with high ductility. An analytical model has been proposed for the nonlinear behavior of composites with off-axis orientation.