Numerical and Experimental Investigation of Concrete-Filled FRP Tube

This study is to investigate nonlinear failure behavior of the concrete-filled FRP (CFFRP) hybrid tube structure. This study consists of two phases. First, a CFFRP tube is fabricated and tested to investigate the flexural failure behavior of CFFRP tube. Second phase involves practical nonlinear finite element analysis of the CFFRP tube up to failure. FRP tube is modeled by layered shell elements and filled concrete is idealized by fiber beam element. Failure theory for the prediction of the strength of unidirectional composite materials is considered. Uniaxial constitutive models for the concrete and steel material are selected in this study. The adopted material model is integrated into the ABAQUS elements through a user-defined material subroutine (UMAT). Within a developed nonlinear finite element framework, the FE results have been compared to experimental results. It has been found that the proposed finite element model is capable of predicting the ini-tial cracking load level, the yield load, and the ultimate load with acceptable accuracy.