载流管线性及非线性振动特性研究

发布时间：2018-02-24 12:11

本文关键词： 载流管非线性动柔度法增量平衡谐波法　出处：《华中科技大学》2015年硕士论文　论文类型：学位论文

【摘要】：载流管在船舶与海洋工程、核电及飞机等现代工业中有着广泛的应用,其振动问题因涉及到流固耦合而备受关注,成为研究的热点。本文运用动柔度法及增量平衡谐波法对载流管的振动特性进行研究,其中线性振动部分主要针对工程中较难处理的带阻尼弹性支撑和复杂几何走向管路系统,非线性振动部分则主要涉及到管路振动机理方面研究。具体内容如下:首先,根据哈密顿原理推导了管路振动的微分方程,在此基础上简单介绍了动柔度法及增量平衡谐波法,给出了其具体的求解步骤。其次,应用动柔度法对载流管包括直管、曲管及三维复杂管路系统的线性振动特性进行了研究。载流直管方面给出了不同边界下载流直管振动特性并与实验进行了对比,验证了公式推导的正确性,另外讨论了加入弹性边界条件后管路振动情况,给出了中间弹性支承下三跨载流直管的计算结果;载流曲管方面,给出了两端固支及一端固支一端弹性支承下管路振动特性,并对结果进行了分析,讨论了弹性支承刚度对管路模态的影响;复杂载流管系统方面研究了一段管路系统的振动特性,给出了不同速度下该管路模态变化情况及幅值频响函数的变化规律。上述计算表明动柔度法适合处理各种支撑边界条件下的复杂管路振动特性计算,特别是针对弹性支承有其独有的方便之处。最后,应用增量平衡谐波法分别研究了两端简支及悬臂载流直管路的非线性振动问题。采用前文介绍的非线性振动模型并进行Galerkin离散成两项谐波项,分别计算了流速、质量比、非线性约束刚度及质量点等对系统振动幅频特性曲线影响,得到了规律性的结论,发现了振动中的幅值突变现象,该工作为增量平衡谐波法应用于载流管非线性振动方面提供了参考和依据。
[Abstract]:The fluid-carrying pipe has been widely used in modern industries such as ship and ocean engineering, nuclear power and aircraft, and its vibration problem has attracted much attention because of its fluid-solid coupling. In this paper, the dynamic flexibility method and the incremental balance harmonic method are used to study the vibration characteristics of the current-carrying tube, in which the linear vibration is mainly aimed at the difficult engineering elastic support with damping and the complex geometric alignment pipeline system. The nonlinear vibration is mainly concerned with the mechanism of pipeline vibration. The main contents are as follows: firstly, the differential equation of pipe vibration is derived according to Hamiltonian principle, and the dynamic flexibility method and incremental balance harmonic method are introduced briefly. The concrete solving steps are given. Secondly, the dynamic compliance method is applied to the flow tube including the straight tube. The linear vibration characteristics of curved tube and three dimensional complex pipe system are studied. The vibration characteristics of straight tube with different boundary download flow are given and compared with the experiment, which verifies the correctness of the formula. In addition, the vibration of the pipe with elastic boundary condition is discussed, and the calculation results of the three-span straight pipe under the intermediate elastic support are given, and the vibration characteristics of the pipe under the elastic support at the two ends and the elastic support at one end are given. The results are analyzed, and the influence of elastic support stiffness on the pipe mode is discussed. The variation of the modal and the frequency response function of the pipeline under different velocities are given. The above calculation shows that the dynamic flexibility method is suitable for the calculation of the vibration characteristics of complex pipes under various bracing boundary conditions. Especially for elastic support has its unique convenience. Finally, In this paper, the problem of nonlinear vibration of straight pipe with simple support and cantilever carrying current is studied by means of incremental equilibrium harmonic method. The nonlinear vibration model described above is adopted and Galerkin is discretized into two harmonic terms, and the flow velocity and mass ratio are calculated, respectively. The effects of nonlinear constrained stiffness and mass points on the vibration amplitude-frequency characteristic curves of the system are obtained, and a regular conclusion is obtained, and the sudden change of amplitude in vibration is found. This work provides a reference and basis for the application of the incremental balance harmonic method to the nonlinear vibration of a current-carrying tube.
【学位授予单位】：华中科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U173

【参考文献】