| Summary: | 碩士 === 國立聯合大學 === 土木與防災工程學系碩士班 === 107 === A tuned mass damper (TMD) is a single-degree-of-freedom (SDOF) system, capable of suppressing the dynamic response of a certain structural mode. One of the essential features of TMD is that its frequency needs to be fine-tuned to maintain its vibration control effectiveness. MTMD (Multiple Tuned Mass Dampers) is an extension of TMD. It is composed of multiple TMD units in parallel to form a band-width of the tuning frequency or to provide multiple tuning frequencies to various structural modes. Thus, an MTMD can be less sensitive to the frequency change than a TMD. Even so, both TMD and MTMD have high stroke demands for mass blocks, increasing difficulties in design and manufacture of its components of damping and resilience.
The purpose of this master's thesis is to initiate a study on a new-type mass dampers, namely the Series Multiple Tuned Mass Damper (SMTMD), comprising of serially interconnected multi-degree-of-freedom TMDs. In this master's thesis, SMTMDs for response control of multi-story buildings with torsionally coupled (TC) effect due to two-way eccentricity of centre of rigidity from the centre of mass of floor were studied. A design theory was developed for the optimization of the SMTMD parameters. Considering the features of floor response of TC buildings, the performance of SMTMD was measured by indices that were established with more than one significant vibration modes of the primary structures. The total mass of SMTMD was assumed to be linearly distributed to each TMD unit with a mass-distribution factor. Both uniform and variant TMD damping and stiffness coefficients were considered. The characteristic and corresponding performance of optimal SMTMD under various parametric conditions were investigated and compared with those of the single TMD. The optimal location of SMTMD on the floor was also investigated. It concludes that an SMTMD is capable of reducing the TC response of multiple modes, while more than one TMD are needed to
achieve the similar control effectiveness.
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