A STUDY ON ULTRA-LOW CYCLE FATIGUE BEHAVIOR OF STRUCTURAL STEELS UNDER CYCLIC COMBINED AXIAL AND FLEXURAL LOADING

Abstract

 This study aims to establish an evaluation method to predict crack initiation and propagation of structural steels till rupture. In this paper, an experimental study on ultra-low cycle fatigue (ULCF) behavior of structural steels under cyclic combined axial and flexural loading was conducted. Effects of the notch shape, notch size and loading history on the crack initiation and propagation behaviors under cyclic loading was investigated. In addition, a proposed three-stage, two-parameter ductile fracture model was employed and numerical fracture simulation was conducted on the experiment specimens. Validities of the model parameter calibration method and the fracture model were discussed through comparisons of the experimental and numerical results.