Influence of Glass Fiber Orientations on the Impact Resistance of GFRP tube Concrete-Encased Steel Composite Member

Abstract

GFRP tube concrete-encased steel member is a new form of composite member. The sudden impacts threaten structural safety and service life, it is important to research the impact behavior of the member. Therefore, to investigate the effect of glass fiber orientation on the impact resistance of GFRP tube concrete-encased steel composite members with fixed-simply supported boundary conditions, a total of 30 finite element (FE) models were developed. Based on the correct finite element analysis method, the working mechanisms were revealed by analyzing the full impact process, energy conversion, bending moment, and shear force distribution. The influence of the fiber orientation on the flexural capacity was discussed. The shear force distributions at typical cross-sections were analyzed. Furthermore, the influence of fiber orientation on impact resistance under different impact locations and slenderness ratios was investigated. The results demonstrate that the fiber orientation can significantly affect the flexural capacity, the impact resistance, and the damage of the members. It is apparent that the bending moment contributed by the GFRP tube and concrete can be improved by placing the fibers along the hoop direction. The members with the range of fiber orientation (75°~90°/±60°~±75°) can effectively enhance the impact resistance, and the effectiveness increases with the development of slenderness ratios. The impact resistance is worst and the damage is severe when the fiber orientation is wrapped only in longitudinal direction. This study can provide a reference for the impact resistance design of the GFRP tube concrete-encased steel composite member.