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直接空冷结构体系是火力发电厂随着空冷工艺出现而形成的一类特殊工业建筑,结构体系及其受力性能复杂。取1/4子结构,模拟边界条件,按1:8缩尺比例制作模型进行风机扰力和地震作用下的试验研究。测试了结构的动力特性,结构与风机的共振点,结构在不同风机转速和风机开启状况下的幅频曲线以及结构构件的动应变。选择ElCentro波对模型进行拟动力试验。得到了结构的动力反应,分析了结构自振频率与阻尼比变化、变形性能、滞回性能和破坏模式等,给出了骨架曲线及其特征点。采用SAP2000有限元程序进行数值计算,分析结果与试验结果基本吻合。研究表明扭转振动是直接空冷结构体系的主要振型,应该考虑振型耦合;风机多点谐振激励引起的结构振动响应较小,风机低频运转对结构的影响大于高频运转对结构的影响。直接空冷结构体系为单道防线体系,大震下结构系统进入非线性后,设备系统能够保持弹性工作状态,结构易形成柱铰破坏机制。
The direct air-cooled structural system is a type of special industrial building formed with the air-cooling process in thermal power plants. The structural system and its stress performance are complex. Take 1 / 4 sub-structures, simulate boundary conditions, make a model according to a 1:8 scaling model for wind turbine interference force and the experimental study under earthquake. The dynamic characteristics of the structure, the resonance point of the structure and the fan, the amplitude-frequency curve of the structure under different fan speeds and fan opening conditions, and the dynamic strain of the structural member were tested. The ElCentro wave was selected to perform pseudo dynamic tests on the model. The dynamic response of the structure was obtained. The changes of the natural vibration frequency and damping ratio, deformation properties, hysteretic properties and failure modes were analyzed. The skeleton curves and their characteristic points were given. Using the SAP2000 finite element program to perform numerical calculations, the analysis results are basically consistent with the test results. The research shows that torsional vibration is the main vibration mode of direct air-cooled structural system, and the coupling of vibration mode should be considered; the structural vibration response caused by multi-point resonant excitation of the fan is smaller, and the influence of low frequency operation of the fan on the structure is greater than the effect of high frequency operation on the structure. The direct air cooling structural system is a single-track defense system. After a large earthquake, the structural system enters nonlinearity, and the equipment system can maintain the elastic working state. The structure is easy to form a column hinge destruction mechanism.