基于二维凸骨料细观模型的混凝土动态力学性能分析

Analysis of dynamic mechanical properties of concrete based on two-dimensional convex aggregate mesoscopic model

建立了细观层次的二维混凝土凸骨料模型,在3.33×10^(-5)、3.33×10^(-4)、3.33×10^(-3)、3.33×10^(-2)、3.33×10^(-1)、0.2 s^(-1)多个应变率下对二维凸骨料模型进行数值分析.从数值模拟结果中可以得到:所建立的二维凸骨料模型在加载后能够较好的反映混凝土力学性能变化;当应变率逐渐增加时,二维混凝土试件的裂纹扩展速度加快,且裂纹走向趋于复杂,数量有明显增多,这与试验中观察到的现象基本一致.加载速率的增大使得混凝土强度逐渐提高;将计算所得抗压强度增大系数与CEB规范及其他学者结果相比较,数值模拟结果较好。

A concrete convex aggregate model based on two-dimensional meso-levels was established.Numerical simulation analysis of mesoscopic model under multiple strain rates of 3.33×10^(-5),3.33×10^(-4),3.33×10^(-3),3.33×10^(-2),3.33×10^(-1),0.2 s^(-1).From the numerical simulation results,it can be obtained that the two-dimensional convex aggregate model established can better reflect the changes in the mechanical properties of concrete after loading.When the strain rate is gradually increased,the crack propagation speed of the two-dimensional concrete specimen is accelerated,and the cracks tend to be more complicated and the number of cracks is obviously increased,which is basically consistent with the phenomena observed in the experiments.The increase of the loading rate makes the concrete strength gradually increase.Comparing the calculated compressive strength increase coefficient with the results of CEB and other scholars,the numerical simulation results are better.