脉动压力谐响应和时程分析的差异性研究

Differences between Harmonic Response Analysis and Time-history Analysis of Pressure Fluctuation

谐响应分析和时程分析是研究水电站厂房结构在脉动压力作用下的振动响应时最常用的2种方法。为分析2种方法的差异性,采用谐响应分析法和时程分析法计算了同一抽水蓄能电站厂房结构在脉动压力作用下的振动响应。对2种方法计算的厂房结构振幅、振动速度、振动加速度和动应力进行对比分析,从而分析2种计算方法的差异性。结果表明:采用谐响应分析法计算的振幅、振动速度和振动加速度的均方根值大于时程分析的计算结果,但峰值小于时程分析的计算结果;厂房结构动应力数值不大,两者的计算结果差别不大。能够获得脉动压力时程资料时,应尽量采用时程分析法计算动力响应;缺乏脉动压力时程资料时,谐响应法也可用来分析动力响应。

Harmonic response analysis and time history analysis are both most commonly used to analyze the vibration responses of powerhouse structure. In order to analyze the differences between these two methods, we calculated the vibration responses of powerhouse structure of a pumped storage station under pressure fluctuations using the two methods. By comparing the vibration amplitude, vibration speed, vibration acceleration and dynamic stresses of powerhouse structure, we obtained the differences between these two methods. Results suggest that the root mean square values of vibration amplitude, vibration speed and acceleration calculated by harmonic response analysis are bigger and peak values are smaller than those calculated by time history analysis. The dynamic stress of powerhouse structure calculated by the two methods are both small and the difference between the results is also small. When the time-history data of pressure fluctuation is available, time history analysis method is preferable ; if not, harmon- ic method can also be used to analyse the dynamic responses of powerhouse structure.