振动波在质量偏心Timoshenko梁非连续处的传播特性研究  

A study on propagation characteristics of vibration waves in a mass eccentric Timoshenko beam when encounter discontinuities

作　　者：王剑 袁秀峰[1] 胡永彪 WANG Jian;YUAN Xiufeng;HU Yongbiao(Eurocrane(China)Co.,Ltd.,Suzhou 215211,China;Department of Construction Machinery,Chang’an University,Xi’an 710064,China)

机构地区：[1]法兰泰克重工股份有限公司,江苏苏州215211 [2]长安大学工程机械系,西安710064

出　　处：《振动与冲击》2022年第20期37-45,77,共10页Journal of Vibration and Shock

基　　金：中央高校基金(300102259107)。

摘　　要：在工程实际中或研究船舶、潜艇等的低频振动时,相应的梁模型有时存在质量中心与形心不重合的情况,此质量偏心会引起弯-纵耦合。该研究以弯曲传播波、弯曲衰减波和纵向波为对象,推导了振动波在Timoshenko偏心梁的弹性支撑、变截面、边界和直角转角处的透射和反射矩阵,重点讨论了振动波的耦合及相互转变效应。分析结果表明:质量偏心率越大,弯曲衰减波越容易转变为弯曲传播波;当频率提高或者偏心率增大时,弯曲波对纵向波的贡献也变大;三种振动波在边界处不会产生耦合效应;当波入射位置存在截面尺寸变化时,弯曲衰减波在新尺寸对应的截止频率处转变为弯曲传播波。In engineering practice or considering low-frequency vibrations of ships,submarines,etc.,sometimes the center of mass and the centroid do not coincide in the corresponding beam model,whereas this mass eccentricity will cause bending-longitudinal coupling effects.Concentrating on flexural propagation waves,flexural attenuation waves and longitudinal waves,the transmission and reflection matrices of these waves at the elastic support,change in cross-section,boundary and right-angle corners of the Timoshenko eccentric beam were derived,and the coupling and transition of waves were discussed in this paper.The results show that enhancement of eccentricity facilitates the transition from flexural attenuation waves to propagation ones.If the frequency or eccentricity is increased,or both,the contribution to longitudinal waves attributes to flexural waves becomes greater.The coupling effects do not arise between the three types of waves at boundary.When there exists an abrupt variation of cross-section at the location where waves emit,the transition of flexural attenuation waves to propagation ones occurs at the cut-off frequency corresponding to the geometric size of this new cross-section.

关 键 词：波形转换 质量偏心 TIMOSHENKO梁 弯-纵耦合 

分 类 号：O326[理学—一般力学与力学基础] U661.44[理学—力学]