定点理論による二自由度系を対象とした動吸振器の設計(第1報，同一の質量と剛性 を持つ二自由度系の場合)

The fixed points theory is applied for the dynamic absorber attached to two degree of freedom system which consists of two identical single degree of freedom systems connected in series. The frequencies of fixed points and the ratio of natural frequencies to equalize the amplitudes at fixed points are analytically derived, in case that the responses at fixed points are in phase. The damping coefficients which make fixed points extremal value are also obtained. Because each of fixed points has different optimal damping coefficient, representative value must be determined. Arithmetic and geometric means of the damping coefficients are considered, and the comparison of the frequency response functions show that the geometric mean is suitable. The analytical solution is compared to the numerically computed results whose responses at fixed points of equal amplitudes are π rad out of phase, and it is shown that these dynamic absorbers have almost same performance of vibration suppression.