Extremely Low Cycle Fatigue Fracture Prediction of Steel Connections under Cyclic Loading

Abstract:

Low-cycle reversed loading test and finite element analysis of a welded connection specimen between square steel tube column and H shape steel beam were conducted. The calibrated micromechanical fracture criteria degraded significant plastic strain (DSPS) model and the cyclic void growth model (CVGM) were used to predict extremely low cycle fatigue fracture initiation for this specimen and the cyclic tests of two side column connection specimens with welded flanges and bolted webs conducted by others. Compared with test results, the predicted fracture location, load cycle number corresponding to fracture, fracture load and displacement have high accuracy. Subsequently, the sensitiveness analyses of damage degradation parameters in micromechanical fracture criteria to the predicted results of fracture were conducted. The results show that the predicted results of fracture are insensitive to the values of damage degradation parameters. Therefore, it is feasible to use the micromechanical fracture criteria to predict extremely low cycle fatigue fracture initiation for steel structure connections under cyclic loading.