基于黏结裂缝模型的混凝土细观损伤模拟

发布时间：2018-05-31 19:47

本文选题：损伤 + 混凝土　；参考：《混凝土》2017年08期

【摘要】：将混凝土视作由骨料、砂浆和交界面层(ITZ)构成,采用黏结特性描述材料界面间的相互作用,建立了混凝土细观黏结裂缝有限元模型。定义混凝土的微裂纹密度和裂纹聚合程度两种损伤度量参数,描述微裂纹的起裂、生长与相互连接汇合乃至试样失效过程。通过对10个试样的拉伸模拟发现了单主裂纹和双主裂纹两种失效模式。对试样平均应力、微裂纹密度和裂纹聚合程度与应变之间关系的分析表明,混凝土在损伤失效过程中存在明显的微裂纹成核区与裂纹聚合区。微裂纹成核造成的初期损伤具有随机性与全场性,导致试样在峰值应力前出现非线性。裂纹聚合造成的后期损伤具有局部化特征,是导致峰值应力后软化的直接原因,并且裂纹聚合程度损伤变量能够反映不同拉伸失效模式的软化特性。
[Abstract]:The concrete is considered to be composed of aggregate, mortar and interfacial layer ITZ. The finite element model of concrete meso-bond crack is established by using the bonding characteristics to describe the interaction between the interface of the material. The microcrack density and crack polymerization degree of concrete are defined to describe the crack initiation, growth and interconnectedness, as well as the failure process of the specimen. Through the tensile simulation of 10 specimens, two failure modes, single main crack and double main crack, were found. The analysis of the relationship among average stress, microcrack density, degree of crack polymerization and strain shows that there are obvious microcrack nucleation zone and crack polymerization zone in the process of damage failure of concrete. The initial damage caused by microcrack nucleation is random and full-field, which leads to the nonlinearity of the specimen before the peak stress. The late damage caused by crack polymerization is localized, which is the direct cause of post-peak stress softening, and the damage variable of crack polymerization degree can reflect the softening characteristics of different tensile failure modes.
【作者单位】：中国工程物理研究院总体工程研究所;
【基金】：国家自然科学基金重大研究计划项目(11390361)
【分类号】：TU528

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