Determination of dynamic characteristics of steel frames by experimental modal analysis method

SUMMARY Determination of Dynamic Characteristics of Steel Frames by Experimental Modal Analysis Method In this thesis, natural frequencies, mode shapes and damping ratios called dynamic characteristics of structures are determined by using experimental modal analysis (modal testing) method. In the experimental modal analysis method, the impact applied to the structure and the response form the structure are measured simultaneously and then transfer function called frequency response function between the impact and response functions is calculated. After that modal parameters belong to the structure are determined by using this transfer function. This thesis consists of five chapters. In the first chapter, firstly general information about experimental modal analysis, the application areas of this method and literature survey are presented. After that, formulations of experimental and numerical modal analysis methods and properties of frequency response function are given. Finally, test equipments used in the experimental modal analysis measurements and modal parameter estimation methods are introduced in detail. In the second chapter, general information about application of experimental and numerical modal analysis methods are presented. After that, selected models and material properties and boundary conditions of models are described. In the third chapter, frequency response functions, coherence functions and modal parameter of each model determined by experimental modal analysis of the models and dynamic characteristics of the models determined by theoretical modal analysis are given. In addition, comparisons of experimental and theoretical modal analysis results are done. In the fourth chapter, conclusions and recommendations obtained from the experimental and theoretical modal analyses are given. In the fifth chapter, the references used in this thesis are presented. In conclusion of this study, it is seen that dynamic characteristics obtained from experimental and theoretical modal analyses are close to each other. Keywords: Experimental Modal Analysis, Frequency Response Function, Dynamic Characteristics, Steel Frames vm