Experimental Modal Analysis Of Boiling Water Reactor Structure Of Nuclear Power Plant

Experimental modal analysis is a kind of analysis techniques determined the structural dynamic characteristics by experiment. Modal parameter identification is not only the core of experimental modal analysis but also the main research direction of structural dynamics, it is an important part of the fields of the structural dynamic characteristics analysis, structural dynamic design, structural fault diagnosis and structural health monitoring, and is also the premise and difficulty.First, this paper researched the basic theory of modal analysis and analyszed the structure and operation principle of boiling water reactors, and introduced the preparation work about measuring points, incentive methods, data acquisition and analysis system, etc, for obtain experimental modal parameter estimations, analyszed the basic characteristics of vibration signal which obtained by test, and prepared model parameter identification procedures. In order to understand the dynamic characteristics of nuclear power boiling water reactor structure provided a reference.Second, this paper used frequency-domain modal parameter identification methods, preprocessing the vibration response signals first, and then according to the stimulus and response signals to strike the frequency response function and get initial parameters. Finally, apply the initial parameters to frequency domain modal parameter identification method to determine the modal parameter estimation. Based on obtained the results of vibration analysis, preparation programs for the display modes, establish and generated simplified geometry model, and then use the animation functions of MATLAB to achieve the animation display of modes.finally, Aiming at the modal parameter identification problems of large-scale structure, on the base of obtained vibration response signals from the structure, comebined the random decrement and NExT technique with time domain methods. Preprocessing vibration response signals with random decrement technique, and then using time domain method to identify the modal parameters, with a view to improving the accuracy of parameter identification. Verifid the applicability and effectiveness of time-domain identification method, and satisfactory results were obtained.