圆柱壳内隔振系统的波动模型及其振动特性

摘要

针对圆柱壳内动力机械的隔振设计问题，建立了由多向扰动振源、斜置弹性支承、两端剪力薄膜支撑各向同性圆柱壳体基础组成的隔振系统解析形式波动模型，并通过有限元法验证了所建模型的有效性。基于 Goldenvei-zer-Novozhilov 薄壳理论和模态叠加原理，考虑弹性支承的分布参数特性，运用子结构导纳法推导了整体系统的耦合振动传递方程，以功率流为价值函数对系统的耦合振动机理进行了探究。数值仿真表明：隔振器的分布参数特性及与基础模态的耦合交互使得高频域系统功率流下降趋势变缓，影响高频隔振设计可靠性；适度增大隔振器斜置倾角，可使系统的各向刚体模态波峰聚集在较窄的频带范围内，同时降低传递到基础的功率流幅值，收到更好的隔振效果；可通过配置合适的隔振器斜置倾角，获取动力机械独立的横向及横摇振动。%In order to deal with the vibration problem about a power machinery installed in a cylinder,the multidimensional cou-pled vibration transfer model which consists of complex excitations,inclined elastic isolators,and a circular cylindrical shell foundation is established.Based on the Goldenveizer-Novozhilov thin shell theory and modal superposition principle,the cou-pled vibration transfer equation of the overall system is derived by using the substructure mobility approach.The power flow concept is used to assess vibration transfer characteristics and isolation performances as a cost function.Numerical simulation shows that:with consideration of the distributed parameter characteristic of isolators,the system power spectrum decline slo-wer at higher frequencies resulting in an unreliable design of high-frequency vibration isolation.Interestingly,if increasing the inclined angle of isolators appropriately,one can make each rigid mode of the system gathered in a narrow frequency range. Meanwhile,the power transmitted to the shell is less than the vertical-mounted case,which leads to a better isolation perform-ance.It can obtain independent transverse and pitch oscillation by changing inclined angle of isolators into a specific value.