FATIGUE ANALYSIS OF FRP MEMBER FOCUSING ON STIFFNESS DEGRADATION OF GFRP

Abstract

 Although it is desirable to examine the structural member level for fatigue verification of GFRP, it is often difficult to conduct member fatigue tests compared to material fatigue tests. Therefore, in this study, we proposed a method to numerically evaluate fatigue damage and member stiffness of GFRP members based on data obtained from material fatigue tests. In the proposed method, we focused on the material stiffness degradation of GFRP with fatigue damage. The stiffness degradation model was implemented in the shell element. The proposed method was examined through FEM analysis using single element model, showed good agreement with the experimental value. Furthermore, the bending fatigue test of a GFRP-concrete composite girder was simulated by the proposed method. The analysis results confirmed that fatigue damage did not occur even after two million loading cycles under the design load. In addition, analysis was performed in which the applied load and loading position were varied, and it was revealed that when fatigue damage occurs in a GFRP hollow member, tensile fatigue damage occurs first on the lower surface of the upper flange.