Characteristics of Chloride Ion Permeation in Concrete of Type Ⅰ Fracture Crack Propagation
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摘要:
为了研究荷载作用下混凝土结构裂缝扩展过程中的氯离子侵蚀问题,更加准确地描述不同扩展阶段裂缝周边的氯离子侵蚀特征,依据混凝土断裂准则,采用ANSYS参数化设计语言APDL进行二次开发,自编程序模拟了混凝土小梁Ⅰ型断裂裂缝开展过程;在断裂分析的基础上通过参数等效,采用结构-热分析方法,基于体应变-损伤变量-氯离子扩散系数一一映射关系,实现了混凝土裂缝扩展过程中各个阶段氯离子侵蚀的数值分析. 结果表明:不同裂缝扩展阶段,三点弯曲混凝土小梁裂缝周边氯离子侵蚀结果与试验结果吻合,荷载作用下混凝土裂缝尖端氯离子侵蚀呈现加剧现象,在混凝土结构耐久性寿命分析中起决定性作用;双
K 断裂准则和基于损伤参数的氯离子扩散模型能够模拟混凝土开裂过程氯离子侵蚀问题.Abstract:To explore chloride ion erosion in the crack propagation process of concrete structures under loads, and more accurately describe the characteristics of chloride ion erosion around cracks at different stages, the development process of concrete trabeculae type Ⅰ fracture, based on the concrete fracture criteria, was simulated by self-programming, and redeveloped by ANSYS parametric design language APDL. Given the mapping relationship between volume strain, damage variable and chloride ion diffusion coefficient, the parameter equivalence method and the structure-thermal analysis method are used for numerical analysis of chloride ion erosion at various stages of concrete crack propagation. The results show that chloride ion erosion around the crack of a three-point bending concrete trabecular is consistent with the experimental one at different crack-expanding stages. The chloride ion erosion at the crack tip of concrete is intensified under loads; therefore, it plays a decisive role in the durability life analysis of concrete structures. Furthermore, the double-
K fracture criterion and the chloride ion diffusion model based on damage parameters can simulate the chloride ion erosion in the concrete cracking process.-
Key words:
- fracture /
- crack /
- chloride ion /
- erosion /
- numerical analysis
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表 1 混凝土基本力学性能
Table 1. Basic mechanical properties of concrete
参量 E/GPa ft /MPa fc /MPa Pmin/kN Pmax/kN 数值 29.2 2.7 34.8 3.14 4.50 -
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