有限应变条件下滞回模式对Q460高强度结构钢的适用性

对不同强度等级结构钢材进行了滞回性能试验研究，设置了等幅升幅、等幅交替和拉伸循环等不同加载路径以研究钢材在地震随机作用下的行为特性。考察了钢板板厚、屈服强度以及加载路径等参数对钢材滞回性能的影响，结果表明，在有限应变条件下，同种牌号不同板厚钢材的滞回性能差异很小，实际屈服强度接近的不同牌号钢材的滞回性能十分接近，不同加载路径下的滞回环有差异但幅度不大，结构钢材具有非完全Masing特性。在此基础上，给出了利用钢材循环加载骨架曲线确定不同应变幅值范围内Ramberg-Osgood方程相关参数的方法，进而建立了滞回环参数随应变幅变化的结构钢材滞回模型，此模型能反映屈服强度以及加载路径等的影响。与Q460钢材滞回试验进行比较，验证了该滞回模型的适用性。

Applicability of cyclic stress-strain relation with limited strain to Q460 high strength structural steel

The hysteretic behavior of structural steels with different strengths was experimentally investigated. The loading protocols including monotonically increasing strain amplitude, repeated strain amplitude and increasing cyclic tensile and compressive strain amplitude were adopted, to consider the steel behavior under random earthquake action. In this paper, the influences of different parameters, such as the thickness of steel plates, the yield strength and the loading protocol, on the hysteretic behavior of steel were studied. The results show that within the limited strain amplitude there is little difference in terms of the hysteretic behavior of steel with different plate thickness. Different steel grades with actually similar yield strengths exhibit similar hysteretic behavior. The influence of loading protocol on the hysteretic behavior of steel is not significant. The results also show that the structural steel behaves non-Masing property. Based on the testing results, a stress-strain model referring to the Ramberg-Osgood function was established, in which the parameters were adjusted with strain amplitude. Influences of the yield strength and loading protocol were taken into account in the hysteretic model. It is shown that the simulation of hysteretic behavior of Q460 steel by the suggested model could be in good agreement with corresponding test data.