多点谐振激励下钢-混凝土竖向混合结构振动响应研究  

STUDY ON VIBRATION RESPONSES OF A STEEL-CONCRETE VERTICAL HYBRID STRUCTURE UNDER MULTIPLE HARMONIC RESONANCE EXCITATIONS

作　　者：朱丽华[1] 白国良[1] 豆攀乔[2] 赵春莲[2] 李红星[2] 

机构地区：[1]西安建筑科技大学土木工程学院,西安710055 [2]西北电力设计院,西安710075

出　　处：《振动与冲击》2008年第3期157-160,共4页Journal of Vibration and Shock

基　　金：国家自然科学基金资助项目(50578129);陕西省科技攻关项目(2006K07-G24);西安建筑科技大学博士创新基金

摘　　要：空冷凝汽器支架结构是由钢筋混凝土管柱和钢桁架组成的竖向混合结构。为了满足工艺要求,在结构中设有多台大直径风机进行强制通风。由于风机的转动偏心不可避免,因而会给结构施加多点谐振激励。为了研究空冷凝汽器支架结构在风机扰力作用下的振动响应,制作了1/8比例模型进行试验研究。试验测试了结构的动力特性,结构与设备的共振点,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。采用ANSYS有限元程序对该结构进行模态分析和谐响应分析,计算结果与试验结果基本吻合。通过试验和有限元程序计算分析的结果,发现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整体的影响要大于高频运转对结构的影响,建议通过合理的构造措施来考虑风机引起的结构疲劳。The air cooled condenser platform is a vertical hybrid structure consisting of reinforced concrete pipe columns and space steel truss with several large-diameter fans installed on it. To study vibration responses of the structure under the excitation of fans, a 1/8 scale model is constructed and tested. The structural dynamic properties, the resonance frequencies of the structure and fans, the amplitude-frequency curves under different rotational speeds and working states of fans, and the dynamic strains of typical structural members are measured in the experiment. Numerical modal analysis and harmonic response analysis are done with ANSYS, and the calculation results are in good agreement with the test results. It is found that the vibration responses of the structure under the excitation of fans are rather slight, and the structural responses at low resonance frequencies are larger than those at high frequencies. It is also suggested to avoid the fatigue effect by rational structural constructing.

关 键 词：钢-混凝土竖向混合结构 振动 风机扰力 谐响应分析 

分 类 号：TU311.3[建筑科学—结构工程]