Abstract
How to find the tuning condition of the new type dynamic vibration absorber is investigated by means of the simplex method, and its results are compared with those of the equivalent linear spring method. At the same time, some experiments are carried out on the model apparatus with an adjustable damping device to ascertain the optimum condition deduced from the above methods. The results are summarized as follows. (1) The optimum distance between the fixed magnets increases as the exciting force is larger. The optimum natural frequency ratio decreases as the growth of the exciting force. These tendencies become more remarkable with the decrease of the mass ratio. (2) The optimum damping ratio of the absorber depends upon the strength of the exciting force, unrelated to the mass ratio. (3) The equivalent linear spring method is considered to be effective to demonstrate the qualitative meaning of the results (1) and (2), by reason that the increase of the exciting force in hard spring contributes to decrease the optimum natural frequency of the absorber. (4) It is easy to adjust the spring action between the magnets and the amount of the damping force to the optimum values, if the adjustable damping device used.
