Research On Modal Parameters Identification And Modal Modification Based On HHT

Hilbert-Huang transform is one of the important theories in signal analysis field，it has widerange of applications in image processing, the structure detection and modal parametersidentification. The time domain method occupies an important position in the field of modalparameters identification, and Natural Excitation Technique is one of most use time domain method.This paper use the method which combined Hilbert-huang transform and Natural ExcitationTechnique to identify the different vibration’s parameters, and construct a structure dynamic model ofplane based on the main population parameter and air test data.This paper first introduces the development process and some latest research results of modalparameters identification and Hilbert-huang transform, and introduces the meaning and main methodof structure dynamic modeling and model modification.Next, this paper introduces the basic theory of Hilbert-huang transform and made the detailedanalysis of empirical mode decomposition algorithm; then introduces the interpolation fittingenvelope, end effect, the intrinsic mode function criterion and modal aliasing phenomenon, made thedetailed analysis of the method which use control the end effect and modal aliasing phenomenon.Made the detailed analysis of using the method which combine the improved Hilbert-Huangtransformation and Natural Excitation Technique method to identify the modal parameters of multidegree of freedom system under pulse excitation, then identify the modal parameters of single degreeof freedom system, multi degree of freedom system and simply supported beam, GARTEUR planemodel, these results verify the reliably and accuracy of paper’s method.In the end, identify modal parameters based on air test data, construct a plane structure dynamicmodel based on the main population parameter, then simplify this model and modify it.