泡沫混凝土单轴压缩破坏特性的细观数值模拟  

Microscopic Numerical Simulation of Damage Properties of Foam Concrete under Uniaxial Compression

作　　者：宋来忠 沈涛 SONG Lai-zhong;SHEN Tao(Three Gorges Mathematical Research Center,College of Science,Three Gorges University,Yichang 443002,China)

机构地区：[1]三峡大学理学院三峡数学研究中心

出　　处：《硅酸盐通报》2019年第6期1823-1831,1860,共10页Bulletin of the Chinese Ceramic Society

基　　金：国家自然科学基金(11171181)

摘　　要：在细观层次,泡沫混凝土可看作是由大量气泡以及水泥浆体这两相材料复合而成的。为了模拟具有高含量气泡的泡沫混凝土,在假设气泡为圆形和球形的条件下,结合随机游走算法与随机搜索算法,创建了泡沫混凝土的二维和三维几何模型。使用混凝土断裂损伤的本构模型,对数值试件进行了单轴压缩破坏的力学特征分析。探究了泡沫混凝土试件从初始微小裂缝直至被压缩破坏的全部过程,得到了泡沫混凝土的应力-应变曲线。结果表明:具有相同气泡尺寸及比例和相同气泡含量,而气泡位置分布不同的泡沫混凝土在抗压强度上有一定的差异性,但峰值应变和初始弹性模量基本保持不变;如果泡沫混凝土的气泡含量不同,那么它的极限抗压强度和峰值应变的变化趋势是不同的,并且随着试件的气泡含量增加,极限抗压强度会快速降低,而峰值应变虽然也会有所降低,但降低的趋势较为缓慢。这与真实的泡沫混凝土在单轴压缩时的破坏过程是一致的。这也说明:数值试验也能够较好的模拟泡沫混凝土在单轴压缩下被破坏的全过程。At microscopic level, foam concrete can be considered as a two-phase composite material, which is composed by artificial introduction of pores and cement paste. In order to simulate foam concrete with high content of bubbles, assuming that the bubbles are circular and spherical, the numerical models of concrete are created by the random walk algorithm combined with random search algorithm. Using the constitutive model of concrete fracture damage, the mechanical characteristics of the uniaxial compression failure of the numerical specimen were analyzed. The whole process of the foam concrete specimen from the initial micro crack to the compression failure was explored, and the stress-strain of the foam concrete was obtained curve. The results show that foam concrete with the same bubble size and proportion and the same bubble content, and different bubble position distribution have certain differences in compressive strength, but the peak strain and initial elastic modulus remain basically unchanged. If the foam content of foam concrete is different, then the ultimate compressive strength and peak strain change trend is different, and as the bubble content of the test piece increases, the ultimate compressive strength will decrease rapidly, while the peak strain will have reduced, but the trend of reduction is slower. These are consistent with the failure process of real foam concrete during uniaxial compression. This also shows that the numerical test can also better simulate the whole process of foam concrete being destroyed under uniaxial compression.

关 键 词：泡沫混凝土 数值模拟 单轴压缩 细观层次 

分 类 号：TU528.2[建筑科学—建筑技术科学]