FINITE ELEMENT ANAYSIS OF CRACKED STEEL WELDED JOINTS RETROFITTED WITH FRP

The fatigue performance of welded steel connections has been generally enhanced by adhesively FRP materials patching. In this study, load-carrying cruciform welded joints with adhesively bonded FRP materials were investigated regarding the fatigue performance. Full penetration weld was proposed as the type of welding. The (2-D) finite element method (FEM) was utilized and modeled for two cases. The first Case during the preliminary analysis to evaluate the effect of using only FRP materials on SIF (KI), while the second case was to study the effect of FRP materials fixed with head plate and bolts on SIF (KI). Stress intensity factors of mode I (KI) were calculated for unrepaired and repaired specimens with various FRP materials by J-integral approach. In addition, FEA results of the unrepaired cruciform joint were verified with an analytical results approach. The reduction of stress intensity factors with FRP patches fixed with head plate and bolts were clarified. Parametric studies were conducted by linear elastic finite element analysis using Ansys software. The different parameters considered in this study are, FRP patch layers, Young's modulus of adhesives, Young's modulus of FRP materials, and initial crack length. Results are shown graphically for these parameters and stress intensity factor.