Damping Model Modeling And Experimental Research On Structural Dynamics Analysis

The dynamic performance of engineering structure has become a key indicator forevaluating the capability and the quality in various sectors, including aerospace, energyand civil engineering. Research on the structural damping presents considerablychallenging in the dynamic analysis as it cannot be determined by the inherentproperties of investigated structures. At present, there is no available database to selectappropriate values. It would therefore be much essential and of great significance toaddress an in-depth investigation. In the study, the modal inertia of structures is firstlydefined by the modal mass and generalized distance. A mathematical model of structuraldamping is then proposed and applied on four different beam structures for relateddynamic analysis. The efficiency and rationality of damping model is lastly verifiedthrough experimental studies.The mechanism of structural damping has been analyzed based on modal strainenergy method and the formulation of the structural damping is present. The structuralvibration at each mode is simplified to that in the main vibration direction. Themathematical model is established by taking into account the natural frequency,structural type and vibration mode, which indicates the linear relationship between thestructural damping and modal inertia. The structural damping is equivalent to thecorresponding Rayleigh damping and Clough damping models, which providestheoretical preparation for its applications in dynamic simulation analysis.Four beam structures have been designed and the finite element models of themhave also been developed. Corresponding pre-stressed modal analysis and experimentshave been undertaken so as to get the structure damping ratio and the modal inertia. Thelinear relationship between the modal inertia and structural damping ratio is established,and the fitting precision is reasonable, which demonstrates reasonable accuracy of thestructural damping mathematical model, which implies the structural damping modelingis reasonable.The harmonic response analysis on the four beam structures has been performedbase on both Rayleigh damping and Clough damping models. The results of formulationfrom Rayleigh damping model and those of Clough damping model all coincide withthe results of the experiments. In addition, the simulation results from the twoequivalent damping models are compared with the frequency response curve ofstructure dynamic experiments, which represents the deviation accuracy for Cloughdamping model is better than Rayleigh damping model., and further illustrates thatcalculates the structure damping in practice is feasible and effective by the structuraldamping model. The proposed structural damping model is simple to use and capable of predictingthe magnitude of damping with reasonable accuracy. From the calculated modal inertia,the structural damping ratio can be derived from the fitted curve. The method whichprepares the theoretical foundation for the calculation of the structural damping.Therefore, it can be widely applied in various structure dynamics analysis.