摘要
Aiming at the impaction among granules of non obstructive particle damping(NOPD), the vibration absorption model for vertical impact of granules is established by adopting Hertz contact theory. The numerical simulation of the granules movement process is proceeded, and the vibration response of a free free uniform beam is obtained for the case when all granules act on it. Through this method, the effect on vibration absorption of impaction is investigated. The simulational data show that multi gra nule vertical impaction is not sensitive to the movement clearance. The vibration absorption is also very well when the clearance changes within a large range. Therefore, the phenomenon that the vibration magnitude may increase if the clearance in a single impact body is improperly selected will not happen. The effect of vibration suppression in the range of middle and high frequencies(2 500~6 000 Hz) is better than that in the range of low frequency(<2 500 Hz). It indicates that the effect on vibration absorption of multi granule can well restrain the vibration of middle and high frequencies.
针对 NOPD中微小颗粒之间的相互碰撞 ,以两端自由的等截面梁为研究对象 ,采用赫兹接触理论建立了多颗粒垂直冲击减振理论模型。进一步对颗粒的运动过程进行了数值仿真 ,得到了梁受到多颗粒冲击时的振动响应 ,籍此研究多颗粒的冲击减振效果。仿真结果表明 ,多颗粒垂直冲击时对其活动间隙值不敏感 ,在较大的范围内仍然有较好的减振效果 ,而且不会出现单冲体间隙选择不当增大系统振幅的现象。对梁中高频段 ( 2 50 0～ 60 0 0 Hz)模态的减振效果明显高于低频段 ( 2 50 0 Hz以下 )的模态 ,这说明多颗粒垂直冲击对系统中高频段的振动有更好的抑制作用。
基金
国家自然科学基金!( 5 9775 0 19)资助项目&&
