630MPa超高强钢筋低周疲劳性能试验研究

630MPa超高强钢筋已应用于实际工程，而目前针对国产630MPa超高强钢筋的低周疲劳性能研究尚未见报道。为此，以我国国产630MPa超高强钢筋为研究对象，对其进行了静力拉伸试验，得到其静拉力学性能参数。通过恒应变幅加载低周疲劳试验，得到疲劳寿命、循环响应特征及应力-应变滞回曲线等指标，研究了630MPa超高强钢筋的疲劳性能，进行了低周疲劳特性评价。在试验研究的基础上，得到了630MPa超高强钢筋疲劳性能参数，建立了其疲劳寿命预测公式。采用OpenSees软件进行了630MPa超高强钢筋材料低周疲劳试验数值模拟，分析表明利用得到的超高强钢筋疲劳性能参数可以较精确地进行630MPa超高强钢筋低周疲劳数值模拟。

Experimental study on low cycle fatigue properties of 630 MPa super-high strength steel bar

The 630MPa super-high strength steel bar has been applied to practical engineering, but there is no research report on the low cycle fatigue performance of 630MPa super-high strength steel bar at present. Firstly, 630MPa super-high strength steel bars made in China were introduced, and the static tensile test of 630MPa super-high strength steel bar was carried out to obtain its static mechanical performance parameters. Then the low cycle fatigue test under constant strain amplitude was performed, and the fatigue characteristics of 630MPa super-high strength steel bar were investigated through indices of fatigue life, cyclic response characteristics and stress-strain hysteretic curves, etc. Based on experimental research, the fatigue performance parameters of 630MPa super-high strength steel bar were obtained, and the fatigue life prediction formula was established. Finally, the OpenSees software was used to simulate low cycle fatigue test of 630MPa super-high strength steel bar. The results show that the fatigue performance parameters of 630MPa super-high strength steel bar obtained from test can be used for numerical simulation.