基于内聚力单元的植筋系统黏结性能有限元分析方法研究

STUDY ON FINITE ELEMENT ANALYSIS METHOD FOR BONDING PERFORMANCE OF POST-INSTALLED REBAR SYSTEM UPON COHESIVE ELEMENT

  • 摘要: 不同材料之间良好的黏结性能是保证其共同受力的基础,也是影响构件力学性能、变形性能的重要因素。有限元分析方法作为试验研究的一种有效补充,诸多学者常采用不同的单元来模拟材料间的界面黏结行为。在总结归纳5种常用黏结单元优缺点及适用条件的基础上,针对混凝土植筋系统的特殊性,提出采用内聚力单元模拟复杂黏结界面的方案,并对不同建模方案下的模拟结果进行对比分析,结果表明:除0厚度内聚力接触外,0厚度单元方案、有厚度单元方案和双界面方案结果均与试验曲线吻合较好,其中双界面模型方案更能准确地模拟植筋系统不同界面的黏结破坏模式。进一步采用双界面模型深入分析胶-筋破坏中双界面的黏结切应力发展和变形规律,重现破坏全过程,深入分析了胶-筋破坏机理并解释了荷载-滑移曲线中的刚度软化现象,充分验证了双界面模型方案用于植筋系统有限元分析的优势和适用性。

     

    Abstract: The excellent performance between different materials is crucial for ensuring their joint load-bearing capacity and significantly influences the mechanical and deformation properties of structural components. Finite element analysis (FEA) is commonly employed to simulate interfacial bonding behaviors, utilizing various element types. After reviewing the advantages, disadvantages and, applicable conditions of five commonly used bonding elements, the cohesive element was recommended to simulate the complex bonding behaviors in a special post-installed rebar system. Comparative simulations revealed that: except for the 0-thickness cohesive contact, the numerical results of 0-thickness element, of the element with thickness and, of the dual-interface model closely aligned with the experimental ones. Among these, the dual-interface model most accurately simulated the bonding damage modes of different interfaces of the post-installed rebar. Further analyses using the dual-interface model obtained the shearing stress and deformation behaviors at the adhesive-rebar interfaces, and reconstructed the entire failure damage process. These analyses reasonably explained the damage mechanism and the stiffness softening phenomenon observed in the load-slip curves. The results validated the advantages and applicability of the dual-interface model for the FEA of the post-installed rebar system.

     

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