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中文核心期刊

钢筋混凝土界面的近场动力学方法

PERIDYNAMIC METHOD FOR THE INTERFACE IN THE REINFORCED CONCRETE

  • 摘要: 近场动力学方法已被广泛用于钢筋混凝土的开裂破坏研究, 传统近场动力学方法的控制方程与参数是基于同种均质材料的能量方程确定, 在处理不同种材料之间的相互作用时, 无法合理反映其界面的力学行为. 针对这一问题, 通过分析钢筋混凝土界面的黏结−滑移机理, 提出了近场动力学界面区材料点的相互作用模型, 发展了考虑钢筋混凝土界面黏结的键基近场动力学方法. 基于键基近场动力学与连续介质力学的能量密度等效方法, 提出了界面微弹性参数的确定方法; 根据钢筋肋间混凝土的应力分布规律, 获得界面材料点域半径与受限楔体半径的等效关系; 利用界面黏结−滑移曲线峰值应力对应的滑移变形, 给出了界面临界拉伸常数确定方法. 通过与2组钢筋混凝土构件的拉拔试验对比, 验证了发展的界面近场动力学方法, 并开展了不同条件下钢筋混凝土构件的数值试验. 结果表明, 发展的近场动力方法能够合理反映钢筋直径、锚固长度、混凝土强度以及肋间距对钢筋混凝土界面黏结行为的影响, 体现了所提方法的合理性与优越性.

     

    Abstract: The peridynamic (PD) method has been widely used to study the cracking and failure of reinforced concrete structures. The control equations and material parameters of the traditional PD method are determined based on the energy equation of homogeneous materials. When dealing with the interaction between different materials, the mechanical behavior of their interfaces cannot be reasonably reflected in the traditional PD method. In order to solve this problem, the interaction model of material points in the interface region of the PD method is proposed by analyzing the bond-slip mechanism of the interface of reinforced concrete. Then the bond-based PD method considering the interface bond of reinforced concrete is developed based on the proposed interaction model. Based on the energy density equivalent principle of the bond-based PD and continuum mechanics, the method to determine the interface micro elastic parameters of the PD is proposed. According to the stress distribution law of concrete between steel ribs, the equivalent relationship between the point radius of interface material and the radius of restricted wedge is obtained. Based on the slip deformation corresponding to the peak stress of the interfacial bond slip curve, a method for determining the critical tensile constant of the interface is presented. So far, the PD method for the interface in the reinforced concrete has been established. By comparing with the pull-out test of two groups of reinforced concrete members, the developed interface PD method of the reinforced concrete is verified, and numerical tests of reinforced concrete members under different conditions are carried out. The results show that the developed PD can reasonably reflect the influence of rebar diameter, anchorage length, concrete strength and rib spacing on the bond behavior of reinforced concrete interface, which well reflects the rationality and superiority of the proposed method, which reflects the rationality and superiority of the proposed method.

     

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