海洋大气环境下锈蚀低屈服点钢材滞回性能与循环加载本构

Hysteretic Behavior and Cyclic⁃loading Constitutive Model of Corroded Low⁃yield⁃point Steel Under Marine Atmosphere Environment

为研究海洋大气环境下隔震耗能元用低屈服点钢材的抗震性能退化问题,本工作开展了LYP100和LYP160钢人工加速腐蚀与循环加载试验,研究了近海环境低屈服点钢材的锈蚀演化规律与滞回行为。结果表明:海洋大气环境下低屈服点钢材呈显著点蚀损伤;随着腐蚀龄期t延长,质量锈蚀率η、锈坑平均深度C与宽度W逐渐增大,而试件截面厚度■逐渐减小;所提出形貌参数■及■对锈蚀表面空间特异性具有显著表征意义,且使其随t增大而愈加离散;另外,随着腐蚀龄期延长与锈蚀参数不断增大,试件屈服平台逐渐消失,加卸载极限峰值应力逐渐回落,耗能能力逐渐退化。当锈蚀两种试件■分别增加至8.4与10.4时,加/卸载峰值应力降低幅度达到16.4%和15.3%,滞回能J分别降低21.0%和23.7%。最后,基于锈蚀低屈服点钢材的同向强化与随动强化,提出了基于Chaboche模型的循环加载本构,并根据锈蚀结果对混合强化参数进行了标定,结果表明:Chaboche模型对锈蚀低屈服点钢材循环加载滞回行为具有较高的模拟精度。本工作可为在役低屈服点钢耗能元(件)的剩余性能评价与合理维护提供理论指导。

To study the seismic degradation of low⁃yield⁃point steel suffered from marine atmosphere environment,artificial accelerate corrosion test and cyclic loading test for two kinds of low⁃yield⁃point steel(named as LYP100 and LYP160)were respectively performed,and corrosion evolution law and hysteretic behavior of corroded specimens under the conditions of offshore environment were studied.The results showed that,under marine atmosphere environment,the pitting damage was obviously discovered on the corroded surface of low⁃yield⁃point steel.With the increase of corrosion time(t),the mass loss rate(η)and the average corrosion parameters(C and W)were increased,while the section thickness(T)was decreased.The morphological parameters(C_(max)/C and W_(max)/W)can reflect the spatial specificity of corroded surface,which become volatilized with t yet.Meanwhile,with the values of corrosion age and corrosion parameters increasing,the yield platform of both two kinds of steel disappear,the loading and unloading peak stresses fall back,and the energy dissipation capacity degrades.While C_(max)/C of LYP100 and LYP160 specimens respectively increase to 8.4 and 10.4,the peak values of stress cycles would be reduced to 16.4%and 15.3%,and the values of J are also reduced to 21.0%and 23.7%.Finally,based on the isotropic and follow⁃up strengthening of corroded low⁃yield⁃point steel specimens,the Chaboche cyclic constitutive model was proposed,and the material parameters of Chaboche model were calibrated by considering corrosive effects.The results showed that,Chaboche model can simulate the hysteretic behavior of corroded structural steel under cyclic loading with high accuracy.This work can provide theoretical guidance for residual performance evaluation and reasonable maintenance of low⁃yield⁃point steel used in energy dissipation elements.