多轴加载下混凝土细观破坏模拟的强度准则探讨

发布时间：2018-03-06 01:03

本文选题：混凝土　切入点：细观尺度　出处：《计算力学学报》2015年03期 　论文类型：期刊论文

【摘要】：实际工程结构中混凝土材料大多处于双轴或三轴的复杂应力状态,已有的细观力学数值研究工作大多针对单轴加载问题,对于双轴或者三轴加载条件下混凝土破坏模拟的研究相对较少。复杂受力条件下的混凝土材料破坏模拟中,细观组分强度准则选取的合理与否将成为混凝土破坏模式及宏观力学性能数值研究准确和成功与否的关键。本文旨在探讨单轴强度准则,如最大拉应变准则在多轴加载条件下混凝土破坏过程研究中运用的合理性。鉴于此,首先在细观尺度上建立了混凝土试件的二维随机骨料模型,分别采用弹性损伤本构关系模型及塑性损伤本构关系模型来描述细观组分(即砂浆基质)的力学性能,对双轴加载条件下混凝土的细观破坏过程进行数值模拟,对比了单轴强度准则和多轴强度准则下混凝土试件破坏路径及宏观应力-应变关系的差异。数值结果表明,简单的单轴强度准则难以反映双轴加载下混凝土内部应力状态的复杂性,不宜采用单轴强度准则来描述多轴加载下混凝土的破坏行为。
[Abstract]:In practical engineering structures, the concrete materials are mostly in the complex stress state of biaxial or triaxial, and most of the existing meso-mechanical numerical researches are focused on uniaxial loading problems. The research on concrete failure simulation under biaxial or triaxial loading is relatively few. The selection of meso-component strength criterion will be the key to the accuracy and success of numerical study on failure mode and macroscopic mechanical properties of concrete. The purpose of this paper is to discuss the uniaxial strength criterion. For example, the application of the maximum tensile strain criterion in the study of concrete failure process under multiaxial loading is reasonable. In view of this, a two-dimensional random aggregate model of concrete specimens is established on a mesoscale scale. The elastic damage constitutive model and the plastic damage constitutive relation model are used to describe the mechanical properties of the meso-component (i.e. mortar matrix), and the meso-failure process of concrete under biaxial loading is numerically simulated. The difference of failure path and macroscopic stress-strain relationship of concrete specimens under uniaxial strength criterion and multiaxial strength criterion are compared. The numerical results show that, The simple uniaxial strength criterion can not reflect the complexity of internal stress state of concrete under biaxial loading, so it is not suitable to use uniaxial strength criterion to describe the failure behavior of concrete under multiaxial loading.
【作者单位】：北京工业大学城市与工程安全减灾教育部重点实验室;
【基金】：国家973计划(2011CB013600) 国家自然科学基金重大项目(91215301) 北京工业大学博士创新基金(YB201207)资助项目
【分类号】：TU528;O346

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