樑式結構之分散吸振器設計分析

Design and Analysis of Discrete Absorbers for Beam-Type Structures

本文提出樑式結構以分散式吸振器抑制共振的設計方法，使用有限元素分析振幅頻率響應以模擬吸振器的效果，探討吸振器參數的影響。樑式結構有多個共振模態需要抑制時，假設樑式結構為多重的單質量彈簧系統，設計獨立的吸振器，令模態吸振器的共振頻率與所針對的模態共振頻率相同，從第一模態開始，依序安裝吸振器於振型位移最大位置，逐模態次數設計分析，設計次一模態之吸振器時，保留之前所安裝的所有吸振器，分析吸振器影響效應的設計參數，包括吸振器之質量比及阻尼比，因而得到吸振器最佳效應的質量、阻尼及彈簧係數。

This paper presents a design and an analysis method of discreteabsorbers for a beam-type structure to suppress resonances. Finiteelement analysis is utilized to simulate the effect of absorbers to explorethe influence of absorber parameters on amplitude-frequency response.Several first resonant modes of beam-type structures that can be seen as amultiple mass-spring system are suppressed by designing individualabsorbers for each mode in sequence. Resonant frequencies of the modalabsorbers are designed to be same as the corresponding mode of thisstructure. From the first mode, each mode is suppressed in sequence bymounting the corresponding modal absorber on the location of maximumdisplacement in the modal shape. For the next mode all absorbers ofprevious modes are reserved. The influence of design parameters, whichare the mass ratio and damping ratio, is analyzed to determine the optimalmass, damping and spring constant of each absorber.