LYP160级钢单调及循环加载性能试验

Experiment on Performance of LYP160 Steel Under Monotonic and Cyclic Loading

为探讨国产LYP160级钢单调及循环加载下的力学性能,对12个LYP160级钢试件进行单调加载试验和多种加载制度下的循环加载试验,分析其单调加载力学性能、本构关系及循环加载应力-应变特性;并基于Ramberg-Osgood模型拟合了不同循环加载制度下LYP160级钢的应力增量-应变增量关系曲线。研究结果表明:LYP160级钢具有良好的塑性变形能力和滞回性能,不同循环加载制度下的应力-应变曲线饱满;其循环加载应力-应变曲线与单调加载应力-应变曲线差异明显,循环加载应变幅值、加载历史对其循环应力-应变曲线影响显著;若循环加载应变幅小于LYP160级钢的强化初始应变,则循环硬化现象不明显,若循环加载应变幅大于LYP160级钢的强化初始应变,则循环硬化现象非常明显;基于Ramberg-Osgood模型能较好地模拟各循环加载制度下的应力增量-应变增量曲线,应变幅逐级增大的加载制度下各应力增量-应变增量曲线较为接近,而应变幅逐级减小的加载制度下应力增量-应变增量曲线与其他加载制度下的应力增量-应变增量曲线差异较大。

In order to investigate the mechanical performances under monotonic and cyclic loading of domestic new LYP160 steel, experiments were carried out on twelve LYP160 steel specimens subjected to various loading protocols including monotonic loadings and cyclic loadings. The mechanical responses of LYP160 steel were evaluated and discussed including its uniaxial stressstrain relation, constitutive relation and hysteretic performance. The stress increment-strain increment curves of LYP160 steel under different cyclic loading were obtained by curve fitting using the Ramberg-Osgood model. The results show that： the LYP160 steel has very good plastic deformation capacity and great hysteretic performance, and all of the stress-strain curves of cyclic loading are full. There are great differences between monotonic stress-strain curves and cyclic stress-strain curves. Cyclic stress-strain curve is significantly affected by the cyclic loading strain amplitude and loading history. If the cyclic loading strain amplitude is less than the strengthening initial strain of LYP160 grade steel, the cyclic hardening phenomenon will not be so obvious. If the cyclic loading strain amplitude is larger than that of strengthening initial strain of LYP160 grade steel, the cyclic hardening phenomenon is very obvious. Besides, the stress incrementstrain increment curves of different loading protocols can be better simulated by the Ramberg- Osgood model, and the stress increment-strain increment curves of loading protocols with progressive increase of strain amplitude are close to each other, while the stress increment-strain increment curves whose strain amplitude decease are different with others.