Explicit approach for the in-plane cyclic behaviors of unreinforced masonry structures using finite particle method
Explicit approach for the in-plane cyclic behaviors of unreinforced masonry structures using finite particle method
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DOI：
10.1016/j.istruc.2023.02.084
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发表时间：
2023-04
期刊：
影响因子：
4.1
通讯作者：
Yanfeng Zheng;Yufeng Kang;Jingyao Zhang;M. Ohsaki;Chao Yang;H. Wan;T. Aoki;Yaozhi Luo
中科院分区：
文献类型：
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作者：
Yanfeng Zheng;Yufeng Kang;Jingyao Zhang;M. Ohsaki;Chao Yang;H. Wan;T. Aoki;Yaozhi Luo
砖石结构，特别是历史建筑，很容易受到地震的影响。在进行改造前，应充分了解其在地震等循环荷载作用下的结构性能。本文将有限质点方法和精细的细观模型相结合，提出了一种分析砌体结构面内循环性能的显式方法。该方法本质上是动态的，可以在同一框架内处理准静态和动态问题。具体地说，为了加速准静态分析，采用了动阻尼法和静力收敛准则。在建模中，基于刚体运动假设，提出了砖的刚体单元。推导了砂浆缝的零厚度界面单元，分析了其在拉伸区、剪切区和复合区的塑性行为。具体地说，充分考虑了循环加载过程中的强度软化、残余塑性位移和刚度退化。对单层砌体墙体在准静力荷载作用下的裂缝线和水平转角曲线进行了分析，结果与试验值吻合较好。在此基础上，研究了两层砌体墙在地震作用下的受力性能，得到了裂缝形态和开裂前后的一阶频率，与振动台试验结果吻合较好。结果表明，由于砂浆缝的断裂，结构的自振频率和层间刚度均有所降低。
Masonry structures, especially historical ones, are vulnerable to earthquakes. Their structural performance subjected to cyclic loadings such as earthquakes should be fully understood before retrofitting. This study proposes an explicit approach for analysis of the in-plane cyclic behavior of masonry structures, combining the finite particle method and an elaborated mesoscale model. The proposed approach is intrinsically dynamic, and it can deal with both quasi-static and dynamic problems in the same framework. Specifically, kinetic damping and static convergence criteria are incorporated to accelerate quasi-static analysis. In the modeling, the rigid element is proposed for bricks based on rigid-body motion assumption. The zero-thickness interface element for mortar joints is derived, and the plastic behaviors in the tension regime, shear regime, and composite regime are developed. Specifically, the strength softening, residual plastic displacement, and stiffness degradation during cyclic loadings are fully considered. A single-story masonry wall subjected to quasi-static loads is analyzed, and the crack lines and horizontal force – rotation curve agree well with those in the experiment. The behavior of a two-story masonry wall subjected to seismic loads is then investigated, and the crack pattern and the first-order frequencies before and after cracking agree well with those in the shaking table test. The results indicate a decrease of the natural frequencies as well as story stiffnesses due to fracture in the mortar joints.