Vibration and Damping Analysis of Rectangular Plate with Partially Covered Constrained Viscoelastic Layer

Dependence of damping characteristics of a beam with damping rubber magnetic powder on rubber property

高分子液晶ER流体を適用することにより, 全方向に対して各運動状態に応じた適切なダンピングを与えることのできるリニアガイドシステム開発のための基礎的検討を行った. 試作したテーブルシステムについて, サーボ軸方向の微小変化に対する性能評価, およびサーボ軸方向と直交する水平方向 (横方向) に関する効果を実験的に検討し, その工学的な有用性を検証した.

Basic Study on Development of A New Linear Guide System with Electrically Controllable Damping Using Liquid Crystalline Polymer

Accurate one dimensional beam modeling method for a rotor shaft with stepped cross-sections in the finite element method

軸直径変化部を有するロータの曲げ振動モードに関する振動計算の高精度簡易モデルの提案(機械力学,計測,自動制御)

The authors have been developing magnetic rubber dampers with a constraining layer (MBDC)-MRDC are easy to install on vibrating steel constructions by the magnetic attractive force of the magnetic rubber layer. The damping property of MRDC is apparently different from the conventional adhesive dampers because the magnetic rubber layer of MRDC slips relatively on the vibrating base layer. Because MRDC are generally installed on steel plate parts of constructions, to install MRDC effectively, it is needed to make clear the damping property of MRDC when installed on steel plate. In the previous paper, the flexural vibration of a plate with a sheet of MRDC was theoretically analyzed taking the relative slip motion into account and the equation to calculate the loss factor of the plate with MRDC was derived. In this paper, the natural frequencies, vibration mode shapes, and the modal loss factors of the plate partially or fully covered with MRDC have been calculated based on the derived equation, and those calculated results have been compared with the data obtained experimentally with the method of resonance. Also, the optimum values for installation area and position have been discussed.

拘束型磁性制振材の制振特性 : 第4報,制振材貼付平板の損失係数の計算と実験検証および最適貼付条件の検討(機械力学,計測,自動制御)

The authors have been developing magnetic rubber dampers with a constraining layer (MRDC). They are generally installed on vibrating steel plates with the magnetic attractive force of the magnetic rubber layer. The damping performance of these MRDC depends mainly on the frictional loss due to the relative slip motion arising between the magnetic rubber layer and the vibrating steel plate. In the previous paper, the flexural vibration of a beam with a sheet of MRDC was theoretically analyzed by taking the frictional loss due to the relative slip motion into account and the equation to calculate the loss factor of the beam with a sheet of MRDC was derived. In this paper, the modal loss factors of the beam with a sheet of MRDC were calculated based on the derived equation, and those calculated values were compared with the data obtained experimentally using the method of resonance. Also, the relationship between the loss factor of the beam with a sheet of MRDC and material properties-magnetic attractive force, the content of ferrite powder, the thicknesses of constraining-, magnetic rubber-, and base-layers has been discussed.

拘束型磁性制振材の制振特性 : 第2報,損失係数の計算および実験検証(機械力学,計測,自動制御)

The authors used Mindlin's equation, and calculated the circular plate natural mode with a solid shaft under the boundary condition of a fixed inner diameter. As the result, the caclulated natural frequency of the low mode of the thick circular plate differed greatly from the one measured by model analysis. The causes were analyzed on the (1, 0) mode of vibration, which had the biggest error of 78 percent. It was revealed that the elastic deformation on the boundary between the circular plate and the solid shaft, and the bending deformation of the had a strong influence on the natural frequency. By taking both influences into account, the natural frequency of the (1, 0) mode was corrected to within a 5 percent error.

軸一体円板の固有振動モードについて : 第1報,円板と軸の境界部の弾性変形と軸の曲げ変形を考慮した固有振動数の補正

The authors induced the spring coefficients which are necessary for the elastic boundary condition in the theoretical modal analysis of circular plates with solid shafts. Because the error of the calculated natural frequencies of the circular plate under the boundary condition of a fixed inner diameter were as large as several tens percent. The spring coefficients are based on the theory of deformation of the semi-infinite plate on which moment is applied. Applying the induced spring coefficients into Mindlin's equation of vibration, the natural frequencies of the circular plate were calculated with an error less than several percents, except for some low modes of vibration such as (0, 0) or (0, 1).

軸一体円板の固有振動モードについて : 第2報 円板と軸の境界部における弾性境界条件式のばね定数

The authors have proposed a basic theory for precisely estimating the frequency response of sound power radiating from plates due to their flexural vibration. In this theory, the equivalent viscous damping ratios of all the natural modes of flexural vibration are required to calculate total loss factor, radiation loss factor and driving point mobility, which are the three most important parameters for the estimation. At present the equivalent damping ratios are only determined using the experimental modal analysis of plates. However, if the damping ratios can be estimated by means of a theoretical method, the radiated sound power may be completely estimated by calculation. As the basis for that, the internal damping of metal is assumed to be viscous damping and is incorporated into the equation of flexural vibration of plates ; then, the relationship between the internal damping and the natural frequency of flexural vibration is derived using Mindlin's thick plate theory.

岩附信行

Papers

拘束型磁性制振材の制振特性 : 第4報,制振材貼付平板の損失係数の計算と実験検証および最適貼付条件の検討(機械力学,計測,自動制御)

拘束型磁性制振材の制振特性 : 第2報,損失係数の計算および実験検証(機械力学,計測,自動制御)

軸一体円板の固有振動モードについて : 第1報,円板と軸の境界部の弾性変形と軸の曲げ変形を考慮した固有振動数の補正

軸一体円板の固有振動モードについて : 第2報円板と軸の境界部における弾性境界条件式のばね定数

内部減衰を考慮した平板の振動モード解析と音響放射パワー推定への応用 : 第1報,モード全損失係数と固有周波数との関係式の導出

岩附 信行

Papers

拘束型磁性制振材の制振特性 : 第4報,制振材貼付平板の損失係数の計算と実験検証および最適貼付条件の検討(機械力学,計測,自動制御)

拘束型磁性制振材の制振特性 : 第2報,損失係数の計算および実験検証(機械力学,計測,自動制御)

軸一体円板の固有振動モードについて : 第1報,円板と軸の境界部の弾性変形と軸の曲げ変形を考慮した固有振動数の補正

軸一体円板の固有振動モードについて : 第2報 円板と軸の境界部における弾性境界条件式のばね定数

内部減衰を考慮した平板の振動モード解析と音響放射パワー推定への応用 : 第1報,モード全損失係数と固有周波数との関係式の導出

岩附信行

軸一体円板の固有振動モードについて : 第2報円板と軸の境界部における弾性境界条件式のばね定数