文章摘要
熊学玉,肖启晟.基于内聚力模型的混凝土细观拉压统一数值模拟方法[J].水利学报,2019,50(4):448-462
基于内聚力模型的混凝土细观拉压统一数值模拟方法
A unified meso-scale simulation method for concrete under both tension and compression based on Cohesive Zone Model
投稿时间:2018-11-26  
DOI:10.13243/j.cnki.slxb.20181061
中文关键词: 混凝土  细观  数值模拟  内聚力模型
英文关键词: concrete  meso-scale  simulation  Cohesive Zone Model
基金项目:国家自然科学基金项目(51578400,5178328)
作者单位
熊学玉 同济大学 土木工程学院, 上海 200092
先进土木工程材料教育部重点实验室(同济大学), 上海 200092 
肖启晟 同济大学 土木工程学院, 上海 200092 
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中文摘要:
      将混凝土内聚力模型的适用范围从原来的细观受拉断裂模拟拓展到了细观受压断裂模拟,并实现了用统一的数值方法来模拟混凝土受压和受拉的细观损伤破坏行为。参考以往的试验研究以及结合内聚力模型的特点,定义了内聚力单元的混合断裂准则以及全局接触关系;建立了不同网格精度的对照模型,讨论了网格敏感性问题;模拟了混凝土在单轴拉伸和压缩作用下的受力全过程,并对断裂能、界面强度、骨料形状和骨料材料类型进行了参数研究;从破坏形态和力学响应的角度探究了混凝土细观断裂和接触行为对整体力学性能的影响。结果表明:较受拉数值模拟,受压数值模拟结果的网格敏感性问题更突出,过粗的网格划分会限制模型的内力重分布;混凝土在单轴受拉时发生的是偏向于Ⅰ型断裂的混合型断裂,其中因Ⅰ型和Ⅱ型断裂能之差所致的混合型断裂能约占受拉总断裂能的一半;骨料颗粒的光滑程度越高,混凝土的单轴极限拉压强度也越高,但颗粒间的机械咬合作用越弱,导致抗压强度退化越快。
英文摘要:
      The application of Cohesive Zone Model is extended to concrete compression fracture simulation at meso-scale. The unity of concrete tension and compression has been realized. Referring to the previous experimental study and the characteristic of Cohesive Zone Model, different fracture behavior under tension and shear, mixed fracture criterion is defined to cohesive elements, and global interaction behavior is de-fined to the model. Specimens with different mesh accuracy are modeled for mesh sensitivity study. The cause of mesh sensitivity in concrete tension and compression simulation are discussed. The whole deforma-tion process of concrete under tension and compression is simulated. A parametric study of fracture energy, interface strength, aggregate shape and aggregate material properties is conducted. The influence of concrete fracture and interaction behavior on the whole mechanic properties are discussed based on the analysis of failure mode and mechanic performance. The study results show that the compression simulation of concrete is more sensitive to the mesh's precision compared with tension simulation,and for the coarse mesh would restrain the internal force redistribution of concrete. The mixed-mode fracture partial to mode I fracture is the main failure mode of concrete under uniaxial tension. The mixed-mode fracture energy caused by the difference of mode I and mode Ⅱ fracture energy comprises 48.2% of the whole tension fracture energy of the specimen. The smoothness of aggregate has a positive effect on uniaxial tension strength,while it would reduce the mechanical occlusion between particles and lead to a higher strength degradation rate.
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