減衰比の温度依存性を考慮した粘弾性体動吸振器の設計手法

抄録

A viscoelastic material is sometimes applied to the damping element of a dynamic absorber. However, since the dynamic characteristics of a viscoelastic material are temperature dependent, it is considered that the vibration damping performance may deteriorate due to changes in the natural frequency and damping ratio. In general, adjustment of its natural frequency is a simple matter of changing the mass and spring stiffness, but adjustment of its damping ratio is more problematic. This paper focuses on the difficulty encountered in adjustment of the damping ratio, proposes a structure for a dynamic absorber capable of suppressing the change in damping ratio due to temperature dependence, and develops a design method. The dynamic absorber is a cantilever type which consists of two plate springs, and a viscoelastic material which is placed between these plate springs. By means of this structure, it is shown that the damping ratio has a gentle curve with respect to temperature characteristics. Moreover, the peak of the damping ratio can be set to the target value at the set temperature by adjusting the thickness ratio of the two plates. The validity of the theory was confirmed by a vibration test using a shaker.