Abstract An eccentricity imperfection may be occurred in the pipes due to the inappropriate manufacturing process. Hence, the dynamic behavior of such geometrically imperfect pipes is extremely required to be explored and compared with the perfect ones. This work investigates the stability and free vibration of fluid-conveying homogenous and functionally graded (FG) pipes with consideration of eccentricity as a geometric imperfection. Three different fluid-conveying pipes are investigated; (i) the homogenous pipe with an eccentricity imperfection, (ii) the FG pipe without imperfection or concentric FG pipe and, (iii) the fluid-conveying FG pipe with an eccentricity imperfection. The governing equations of the fluid–structure interaction system are derived by including the effect of shear deformation using the Timoshenko beam theory. The finite element method is applied to discretize the governing equations and solve the eigenvalue problem of a clamped-clamped pipe. Consequently, the complex modal analysis is used to obtain the natural frequencies and critical velocities of homogenous and FG pipelines with and without eccentricity imperfection. Finally, the effects of different magnitudes of eccentricity and power-law exponent on the critical fluid velocity are investigated. This investigation is expected to provide more insight for the applications of geometrically imperfect pipes in the pipeline systems.

中文翻译：

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偏心缺陷对流体输送功能梯度管道稳定性和振动行为的影响

摘要 由于制造工艺不当，管道可能会出现偏心缺陷。因此，非常需要探索这种几何不完美管道的动态行为并与完美管道进行比较。这项工作研究了流体输送均质和功能梯度 (FG) 管道的稳定性和自由振动，并考虑了偏心作为几何缺陷。研究了三种不同的流体输送管道；(i) 有偏心缺陷的同质管道， (ii) 没有缺陷的 FG 管道或同心 FG 管道，以及 (iii) 具有偏心缺陷的流体输送 FG 管道。流固耦合系统的控制方程是通过使用 Timoshenko 梁理论包括剪切变形的影响推导出来的。应用有限元方法对控制方程进行离散化，求解夹钳管的特征值问题。因此，复模态分析用于获得具有和不具有偏心缺陷的均质管道和 FG 管道的固有频率和临界速度。最后，研究了不同大小的偏心率和幂律指数对临界流体速度的影响。这项研究有望为几何缺陷管道在管道系统中的应用提供更多见解。复模态分析用于获得具有和不具有偏心缺陷的均质管道和 FG 管道的固有频率和临界速度。最后，研究了不同大小的偏心率和幂律指数对临界流体速度的影响。这项研究有望为几何缺陷管道在管道系统中的应用提供更多见解。复模态分析用于获得具有和不具有偏心缺陷的均质管道和 FG 管道的固有频率和临界速度。最后，研究了不同大小的偏心率和幂律指数对临界流体速度的影响。这项研究有望为几何缺陷管道在管道系统中的应用提供更多见解。