Abstract：The present study aims to investigate the effects of stress ratio and specimen orientation on fatigue crack growth (FCG) behavior of HRB400 steel bar with a diameter of 40 mm. Two types of FCG tests on compact tension (C(T)) specimens are conducted: the constant load amplitude FCG test for obtaining the Paris’ region behavior and the load-decreasing FCG test for determining threshold stress intensity factor range. Five stress ratios are considered, i.e., 0.02, 0.1, 0.2, 0.3 and 0.5. The crack propagation directions are classified into two conditions, i.e., crack propagates in radial or axial direction. Following this, the morphology of fracture surface is examined by scanning electron microscope. Finally, the FCG rates, thresholds and morphology of fracture surface under different test conditions are compared. The experimental results show that the banded ferrite-pearlite is apparent and parallel to the axis of steel bar. The FCG rate increases and the threshold decreases as the stress ratio increases. A transition point exists in the initial stage of radial FCG curve. The axial FCG behavior is more sensitive to the variation of stress ratio. The material exhibits a better resistance to FCG in radial direction than that in axial direction. The ductile and brittle fracture characteristics are obviously presented in radial and axial specimens, respectively. The radial and axial fatigue crack appears predominantly to be the transgranular and intergranular fracture mode, respectively.
郭忠照 马亚飞 王磊 张建仁. HRB400钢筋材料疲劳裂纹扩展性能试验研究[J]. 土木工程学报, 2018, 51(7): 112-120.
Guo Zhongzhao Ma Yafei Wang Lei Zhang Jianren. Experimental study on fatigue crack growth behavior of HRB400 reinforcing bar. 土木工程学报, 2018, 51(7): 112-120.
