中文摘要：

结构振动是多个振型参与的结果。在结构抗震设计及地震工程相关领域,结构模态数值的应用程度越来越高,其准确程度从根本上关系到结构设计和工程抗震的实现效果。为考察阻尼对实际结构模态测试结果的影响,设计了三层剪切型钢框架模型及可调硅油阻尼器。计算其理论模态,并通过三种常用的模态测试方法,对其在阻尼比由小到大逐渐增大的各种工况下的频率和振型进行测试。试验结果表明：阻尼比对结构模态测试结果确有影响,测试精度随着阻尼比的增大而降低,但在实际结构阻尼比量级时,常用测试方法得到的简单结构的模态结果精度可以满足工程计算需要;脉动法、初位移释放法和激振法的测试精度依次提高。

英文摘要：

Structural vibration is the superposition of different modes. As the application of structural modes is paid more attention in the field of earthquake engineering, the measuring accuracy of structural modes has a direct bearing on the realization of the seismic design desire. A 3-story shearing steel frame model with an adjustable damper achieved by silicon oil was designed to study the influence of damping in the structural modal test. Theoretical values of the structural frequencies and modes were calculated. And then the measured values under different damping were acquired by three common test methods. Test results show that damping ratio affects the modal testing results. The testing accuracy decreased with the increasing of damping ratio. But the engineering accuracy can be satisfied by using the three common test methods for the simple test model with a damping ratio of the actual engineering structure. The testing accuracy for natural excitation method, initial displacement releasing method and excitation method increases gradually.