锈蚀钢筋混凝土梁弯曲疲劳性能的材料——结构协同数值模拟研究

Material-structure collaborative numerical simulation of flexural fatigue behavior of corroded reinforced concrete beam

以路径依赖的率型混凝土本构模型为基础,采用多尺度有限元模拟方法 DUCOM-COM3,并结合试验对钢筋混凝土梁的静载、疲劳以及锈蚀疲劳耦合性能进行了分析研究。结果表明,路径依赖的混凝土本构模型能够更好地模拟复杂的往复荷载工况,同时通过多尺度建模可将锈蚀引起的材料损伤与疲劳荷载引起的结构损伤协同分析。针对无锈蚀适筋钢混梁的疲劳分析表明,其S-N曲线大致呈双线性模式。对于锈蚀钢混梁,其疲劳寿命随着锈蚀率增大而线性减小,且锈胀裂缝对于锈蚀构件疲劳寿命减小有着显著影响。若以锈蚀损伤后梁的承载力重新定义荷载等级,则锈蚀钢混梁的S-N曲线与无锈蚀S-N曲线接近。最后,结合数值分析和理论模型,对中低荷载水平下适筋钢混梁的疲劳破坏模式进行了机理性分析。

Based on path-dependent rate-type concrete constitutive model,it adopts multi-scale finite simulation method DUCOM-COM3 and analyze the static,fatigue and corrosion-fatigue coupled performance of reinforced concrete beam combined with experiment results.The analysis results shows that the path-dependent concrete constitutive model could simulate structural behavior well under complex cyclic loading conditions.Meanwhile,the structure fracture induced by material corrosion damage and fatigue loading can be collaboratively analyzed by multi-scale modeling.Fatigue behavior analysis of non-corroded reinforced concrete beam shows that S-N curve almost exhibits bilinear model.For corroded reinforced concrete beam,structural fatigue lives decrease linearly with corrosion rate increase,and corrosion cracks have a significant influence on fatigue life deterioration of corroded structure.When loading level was redefined by post-corrosion monotonic loading capacity,the S-N curve of corroded beam is close to that of non-corroded beam.Lastly,fatigue failure mode mechanism of balanced-reinforced concrete beam under middle or low load level is analyzed combined with numerical simulation and theoretical calculation methods.