村镇建筑砌体结构的动力特性分析

Dynamic Characteristics of Masonry Structures in Villages and Towns

为探讨村镇建筑中低层砌体结构的动力特性与振动机理,基于农居调查实测的布置及材料性能数据,在ABAQUS软件中建立考虑结构布置、材料强度及有限元网格控制等参数的7个有限元模型方案,对各模型进行结构动力特性分析,并对比分析其振动形态、振型分量及振型周期。分析表明,村镇建筑中按常规布置的砌体结构,其振动特性不利于结构抗震;砌体材料性能劣化在降低结构承载能力的同时还会放大高阶面外振动分量的地震作用,加剧承重墙在地震中发生外闪倒塌的机率;如采取措施实现结构的基本振型为沿横向平动,则其振动特性表明横墙的承重与抗侧能力均可有效发挥,且面外振动的高阶振型被抑制,提高了结构抗震能力;此外,本文还提出ABAQUS对壳单元沿厚度方向的网格控制要求。

To research the dynamic characteristics and vibration mechanism of low-story masonry structures in rural buildings,we used ABAQUS to establish seven finite element models based on a survey of rural buildings.In the models,we considered structure layout,strength of the materials,and mesh density.Then,we analyzed the dynamic characteristics of each model and compared their vibration shapes,modal components,and vibration periods.The results show that the vibration characteristics of traditional masonry structures are not conducive to seismic design and that the degradation of materials reduces the bearing capacity of the structures,while at the same time amplifying the seismic action of the wall oscillation component,which increases the probability of outward collapse in earthquake.If the basic vibration type is horizontal along the transverse direction,the seismic capacity of the structure is improved with respect to both the bearing and deformation abilities of load-bearing walls.In addition,we propose ABAQUS mesh requirements for shell elements with respect to thickness.