加振周波数の変動範囲を考慮した動吸振器の設計法

抄録

A new optimum design method of dynamic vibration absorbers is proposed for the cases when the primary system has some uncertainty in dynamic characteristics and excitation frequency fluctuates in small range. When the excitation frequency is constant, it is well known that an undamped dynamic vibration absorber is very effective to attenuate the vibration amplitude of the primary system. However, when the excitation frequency fluctuates in small range, such an undamped absorber does not always suppress the vibration amplitude. In this paper, we find out that upper limit of the vibration amplitude of the primary system can be estimated easily by using the imaginary part of the dynamic stiffness of the absorber. We derive very simple equations which give the optimum natural frequency and damping ratio of the absorber for given excitation frequency range. Calculation results of the frequency response for some examples designed by the proposed method are demonstrated and they show the usefulness of the proposed method.