Predicting Low Cycle Fatigue Life through Simulation of Crack in Cover Plate Welded Beam to Column Connections

This paper presents a low cycle fatigue life curve by simulating a crack in a cover plate welded moment connection. Initiation of ductile fracture in steel is controlled by growth and coalescence of micro-voids. This research used a numerical method using finite element modeling and simulation of ductile crack initiation by a micromechanical model. Therefore, a finite element model of a cover plate welded moment connection was developed in ABAQUS software, and a FORTRAN subroutine was used in order to simulate cracking in the connection model. Thus, each crack location and the number of cycles to initiate the crack were detected. Utilizing cyclic void micromechanical model of growth analysis, which is a technique to predict fracture in a ductile material, six different cover plate connections (divided in three categories) were modeled in the steel moment frame, and then their critical points to trigger the crack were identified. Finally, for the cover plate moment connection, considering the constant amplitude of loading curves data and in order to present the low cycle fatigue life prediction, displacement versus the number of half cycles diagram is produced.