河冰单轴压缩破坏过程细观数值仿真

为了解并认知河冰材料的内在属性,对黄河封冻期的河冰进行了现场取样观测并开展了单轴抗压破坏过程的物理试验,依据物理试验结果,在细观层面将河冰看成由晶粒、晶界、初始缺陷构成的非均质材料,给出了随机缺陷界面弹簧元模型模拟河冰单轴压缩强度的数值方法,模拟了河冰在单轴受压荷载作用下的开裂破坏过程,分析了初始缺陷分布和含量、晶粒尺寸等各相组分对河冰力学性能的影响。结果表明:随着初始缺陷含量的增加,河冰单轴压缩强度呈下降趋势,但下降幅度逐渐变缓;随着晶粒尺寸的增加,河冰单轴压缩强度呈降低趋势,且与晶粒尺寸d-1/2呈线性相关关系。与物理试验对比发现,该计算模型能较好地模拟黄河冰的单轴压缩强度和开裂过程。

Numerical simulation of uniaxial compression failure process of river ice

In order to understand the intrinsic property of river ice,the river ice of Yellow River was sampled and carried out observation in freezing period, the uniaxial compression failure tests were accomplished. According to the results of physical test, the river ice was considered as a heterogeneous material consisting of grain, grain boundary and initial defects at mesoscopic scale. A numerical model was established to simulate the cracking process of river ice under uniaxial compression load. The effects of initial defect distribution and contents, grain size and other components of the river ice on its strength were analyzed. The results show that the uniaxial compressive strength of river ice decrease with the increase of initial defect contents, but the decreasing extent gradually slows down. With the increase of grain size, the uniaxial compressive strength decreases, and it has a linear correlation with the d^-1/2 of grain size. Compared with the physical experiment of the Yellow River ice, the results of mesoscopic model are in good agreement with the uniaxial compressive strength and cracking process.