冻融循环作用下含缺陷混凝土三维数值模拟

Three Dimensional Mesoscopic Numerical Simulation of Concrete with Defects under Freeze-thaw Cycles

目的 基于细观尺度理论,对冻融循环作用下不同孔隙缺陷的混凝土抗压强度进行参数化研究。方法 制作不同孔隙缺陷的混凝土立方体试件,并进行冻融循环加载试验;运用Python驱动ABAQUS内核,建立三维球形和椭球形随机骨料模型;通过模拟与试验对比分析两种骨料模型对混凝土抗压强度的影响,进而选取效果更优的骨料模型进行含缺陷混凝土的热-力学数值模拟分析。结果 椭球形随机骨料模型的模拟结果与试验数据更吻合;相同冻融循环次数下,含5%孔隙缺陷相比于不含孔隙缺陷混凝土的抗压强度、初始弹性模量明显下降。结论 骨料几何形状对混凝土抗压强度影响较小,孔隙缺陷对冻融环境下混凝土的力学特性具有不可忽视的影响。

Based on meso-scale theory, the compressive strength of concrete with different pore defects under freeze-thaw cycles was studied by parameterization.Concrete cube specimens with different pore defects were made and freeze-thaw cyclic loading tests were carried out.The ABAQUS kernel was driven by Python to establish 3D spherical and ellipsoidal random aggregate models.The influence of the two aggregate models on the compressive strength of concrete was analyzed through the comparison of simulation and experiment, and then the aggregate model with better effect was selected for the thermo-mechanical numerical simulation analysis of the concrete with defects.The simulation results of ellipsoidal random aggregate model are more consistent with the experimental data.Under the same freeze-thaw cycles, the compressive strength and initial elastic modulus of concrete with 5% pore defects decreased significantly compared with that without pore defects.The aggregate geometry has little influence on the compressive strength of concrete, and the pore defects have significant influence on the mechanical properties of concrete in freeze-thaw environment.