【摘要】 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。更多还原

【Abstract】 The direct air cooled condenser support platform is a special industrial building, and it appears with the application of air cooled technology in thermal power plants. The structural form and its mechanical performance are very complex. Employing 1/4 substructure, imitating the boundary condition, a 1/8 scale model was constructed and tested to study its mechanical behavior under excitation of fans and earthquake action. The structural dynamic properties, the resonance vibration frequency of structure and fans, the amplitude-frequency curve under different rotational speed and work state of fans, and the dynamic strain of typical structural members were measured. Then in the pseudo-dynamic test, the model was subjected to El Centro wave, and the dynamic response of the structure was measured. The variation of natural frequency of vibration and damping ratio, the deformation performance, the hysteretic behavior and the failure mode of the model were analyzed. The skeleton curve of the model and its characteristic points were presented in this paper. Finite element analysis was performed using commercial computer codes, and the calculation results show agreement with the experimental results. The study indicated that torsion was one of the main vibration shapes of the structure, so the couple of vibration shapes must be considered. The vibration response of the structure under the multiple harmonic resonance excitations of fans was very weak, and the structural response at low resonance vibration frequency was larger than high frequency. The direct air cooled condenser support platform was a single-prevention system, and the equipment system was in elastic working state when the structure system yielded under seldom-occurred earthquake action and the structure failed in the column hinge mechanism.更多还原