Parametric Optimization Of Passive Tuning Type Dynamic Vibration Absorbers

Structures vibrate when they are subjected to Dynamic Loadings, such as earthquake andstrong wind. Structural exceeding vibration may cause discomfort to occupants, malfunctionof equipement or even structural failure. How to suppress structural vibration induced bydynamic loadings has become one of the most popular subjects in Civil Engineering. Up tonow, passive tuning type dynamic vibration absorbers have been involved in a largepercentage of engineering applications. Therefore, the study on the optimization of dynamicvibration absorber is of particular importance to theoretical research and practical application.The thesis focus on the optimization problems of three types of regular passive tuningtype dynamic vibration absobers, Tuned Mass Damper (TMD), Tuned Liquid/SloshingDamper (TLD or TSD) and Tuned Liquid Column Damper (TLCD) and the main contents aresummarized as follows:(1) The importance of structural vibration control is shown first and the structuralvibration control methods are introduced. Then the history and present status of the researchon various types of dynamic vibration absobers are summarized.(2) Models of the dynamic vibration absorbers are presented. The models of TMD andTLCD are relatively simple, however the model of TLD is very complex due to thenonlinearity of the sloshing motion. Several models suitable for engineering optimizationdesign are selected after having reviewed lots of available literature on the subject.Furthermore, the scopes of application of these models are recommanded.(3) The fundamental ideas and methods for optimizing TMD are reviewed. Based on anonlinear model of TLD, the optimization researches of parameters that influence theeffectiveness of TLD are conducted. And some conclusions that have not been found by usinglinear model of TLD are obtained.(4) The optimization of non-uniformly distributed MTMD is studied in detail. Solving anunrestricted multiple objectives optimization problem, the optimum parameters of thenon-uniformly distributed MTMD to minimize the response of main structure in frequencydomain are obtained. It is very convenient to take possible estimation errors of parameters ofthe structure and TMDs into account. The results show that the optimal non-uniformlydistributed MTMD is more effective than the uniform one and the non-uniformly distributed MTMD can be more robust if the possible errors of estimate are considered in the designprocess. The applicability and effectiveness of the method proposed here are validated.(5) Based on Ant Colony Optimization (ACO), an optimization design method ofmulti-mode vibration control for tall structures using MTMD is presented. The optimizationof MTMD for a 20-story building subjected to various earthquake records is persented as anexample. It is shown that the ACO algorithm is very suitble for optimizing the massdistribution of dampers that control different vibration modes when MTMD is used to reducethe multi-mode responses of the structure.