| 基于一类非局部宏-微观损伤模型的混凝土典型试件力学行为模拟 |
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| 引用本文： | 任宇东,陈建兵.基于一类非局部宏-微观损伤模型的混凝土典型试件力学行为模拟[J].力学学报,2021,53(4):1196-1121. |
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| 作者姓名： | 任宇东 陈建兵 |
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| 作者单位： | 同济大学土木工程学院, 土木工程防灾国家重点实验室, 上海 200092 |
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| 基金项目： | 1)国家杰出青年科学基金(51725804) |
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| 摘 要： | 混凝土是一类典型的准脆性材料, 其受力过程中的非线性分析与裂纹模拟依然是具有挑战性的问题. 经典的断裂力学与损伤力学分别从间断与连续的视角对裂纹拓扑进行了描述, 是早期人们研究固体破坏问题的有力工具. 21世纪以来, 相场理论和近场动力学在预测裂纹的萌生、扩展与非线性分析方面取得了重要的进展. 最近, 结合统一相场理论与近场动力学的基本思想, 发展了一类非局部宏-微观损伤模型. 该模型引入物质点偶的概念来刻画由于变形引起的微细观损伤, 对微细观损伤在作用域中进行加权平均得到定量描述物质不连续程度的拓扑损伤. 通过具有物理机制的能量退化函数, 将拓扑损伤嵌入到连续介质-损伤力学的框架中, 这使得该模型在进行非线性分析的同时可以自然地进行裂纹模拟, 而毋须预设初始裂纹与裂纹扩展路径. 本文考虑细观物理参数的空间变异性, 采用非局部宏-微观损伤模型进行混凝土试件受力全过程的精细化模拟. 通过一维建模标定模型细观参数, 并探讨了细观参数与混凝土材料细观物理-几何特性之间的内在关联, 在此基础上采用二维模型进行精细化分析. 进而, 考察了材料参数空间变异性对混凝土单轴受拉试件和带缺口三点弯曲试件力学行为的重要影响. 本文的研究工作为非局部宏-微观损伤模型细观参数的试验标定与复杂应力状态下混凝土等准脆性材料的非线性力学行为研究提供了有意义的参考.
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| 关 键 词： | concrete nonlocal macro-meso-scale consistent damage model uniaxial tension parameter calibration parameter spatial variability |
| 收稿时间： | 2020-12-13 |
SIMULATION OF BEHAVIOUR OF TYPICAL CONCRETE SPECIMEMS BASED ON A NONLOCAL MACRO-MESO-SCALE CONSISTENT DAMAGE MODEL |
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| Affiliation: | College of Civil Engineering & State Key Laboratory of Disaster Reduction in Civil Engineering, Tongji University, Shanghai 200092, China |
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| Abstract: | Concrete is a typical quasi-brittle material, and the nonlinear analysis and crack simulation of concrete during loading are still challenging issues. Classical fracture mechanics and damage mechanics describe crack topology from discrete and continuous perspectives respectively, and became two of the most powerful tools for solid crack simulation and prediction problems. Since the beginning of this century, in the phase field theory and peridynamics significant progress has been made in predicting the crack initiation and propagation and nonlinear analysis. Recently, a new nonlocal macro-meso-scale consistent damage (NMMD) model has been developed based on the basic ideas of phase field theory and peridynamics. In this model, the concepts of material point pair are introduced to characterize the meso-scale damage due to deformation. Then the topologic damage which quantifies the degree of discontinuity in macroscopic solid is defined as the weighted average of meso-scale damage in the influence domain. Through the physically-based energetic degradation function which bridges the topologic damage and energy dissipation, the topologic damage can be inserted into the framework of continuum damage mechanics, which allows this model to simulate the crack process naturally while performing nonlinear analysis without prescribed initial crack and potential propagation path. The present paper takes into account the spatial variability of the meso-scale physical parameters and employs the NMMD model to simulate the whole loading process of typical concrete specimens. The model meso-scale parameters are calibrated through the 1D modeling firstly, and the relationship between the meso-scale parameters and the meso-scale physical-geometric properties of concrete is discussed. Based on the 1D-calibrated parameters, a detailed analysis through the 2D NMMD model is performed. Further, the influence of material parameter spatial variability on the behaviors of uniaxial tensile concrete specimen and notched three-point bending beam is investigated. The work in this paper provides a meaningful reference for the calibration of meso-scale parameters in the NMMD model and the investigation on nonlinear mechanical behavior of concrete and other quasi-brittle materials under complex stress state. |
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