低屈服点钢低周疲劳性能研究

近年来，低屈服点钢因其优越的耗能能力而广泛应用于结构抗震中。为了对国产低屈服点钢的低周疲劳性能进行研究，本文对牌号为LY100、LY160及LY225的低屈服点钢进行了大塑性变形下的低周疲劳试验，试验采用应变控制的等幅循环加载，分析了其破坏现象、循环应力响应特征、循环骨架曲线、滞回曲线特点等性能，并基于不同的模型对其低周疲劳寿命进行了预测。结果表明：国产低屈服点钢具有良好的抗低周疲劳能力；Ramberg-Osgood模型可以很好地拟合钢材循环应力-应变曲线；Manson-Coffin模型及Kuroda模型均可有效拟合低屈服点钢的低周疲劳寿命曲线，其中Manson-Coffin模型的拟合精度较好，而Kuroda模型更适用于大应变下疲劳寿命预测。

Low cycle fatigue properties of low yield point steels

  Due to its excellent energy dissipation capacity, the low yield point steel has been widely used in seismic design in recent years. In this work, the low cycle fatigue properties of low yield point steel LY100, LY160 and LY225 were tested under the large plastic deformation. The failure modes, cyclic stress response characteristics, cyclic stress-strain curves and the hysteretic curves were analysed, and the low cycle fatigue life curves were fitted and predicted based on the Manson-Coffin model and Kuroda model respectively. The results show that domestic low yield point steel has good capability to withstand low cycle fatigue; the Ramberg-Osgood model can fit well with the stress-strain curves; both Manson-Coffin model and Kuroda model can effectively match the low fatigue life curves, and the fitting effect of Manson-Coffin model is better, while Kuroda model is more applicable to fatigue life prediction under large strains.