含摩擦界面复合材料输流管道非线性振动分析
NONLINEAR VIBRATION ANALYSIS OF A COMPOSITE PIPE CONVEYING FLUID WITH FRICTION INTERFACE
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摘要: 针对含摩擦界面复合材料输流管道流固耦合动力学问题, 基于Reissner薄壳理论和对流波动方程建立了纤维增强复合材料管道和流体介质的动力学方程, 采用宏观滑移摩擦模型刻画管道摩擦界面上的非线性摩擦力分布, 发展轴对称半解析有限元方法来构建含摩擦界面复合材料输流管道非线性动力学模型, 研究了流体载荷和摩擦界面等对管道非线性振动响应的影响. 结果表明, 含摩擦界面复合材料输流管道摩擦界面上点的滞回曲线由两个对称的黏滞区域和两个对称的滑移区域组成, 摩擦界面的黏滞-滑移切换导致输流管道振动响应除包含激励频率外, 还包含一系列奇次超谐波; 随着界面摩擦系数增大, 输流管道基频处的轴向振幅减小, 法向振幅增大, 而3次超谐波处的轴向及法向振幅先增大后减小; 随着界面摩擦刚度增大, 输流管道基频及3次超谐波处的轴向振幅先减小后增大; 来流速度主要影响含摩擦界面输流管道的法向振动, 对管道的轴向振动影响很小.Abstract: To solve the fluid-structure interaction dynamics of a composite pipe conveying fluid with friction interface, an axisymmetric semi-analytical finite element method is developed to construct a nonlinear dynamic model. The dynamic equations of fiber-reinforced composite pipe and fluid medium are established based on the Reissner’s thin shell theory and the convected wave equation. A macro-slip friction model is adopted to describe the distribution of nonlinear frictional forces on the friction interface. The effects of fluid load and friction interface on the nonlinear vibration response of the pipe conveying fluid are examined. The results show that the hysteresis loop of points on the friction interface of the composite pipe conveying fluid with friction interface consists of two symmetric stick regions and two symmetric slip regions. The stick-slip transition of the friction interface causes the vibration response of the pipe conveying fluid to contain not only the excitation frequency but also a series of odd-order super-harmonics. As the friction coefficient of the interface increases, the axial vibration amplitude of the pipe conveying fluid at the fundamental frequency decreases while the normal vibration amplitude increases, and both the axial and normal vibration amplitudes of the pipe conveying fluid at the third-order super-harmonic first increase and then decrease. As the friction stiffness of the interface increases, the axial vibration amplitude of the pipe conveying fluid at the fundamental frequency and the third-order super-harmonic first decreases and then increases. The flow velocity mainly affects the normal vibration of the pipe conveying fluid with friction interface and has little impact on the axial vibration of the pipe.