In this paper, the dynamics of a viscoelastic pipe conveying fluid attached to a nonlinear energy sink (NES) subjected to a sinusoidal flow is studied, aiming at performance improvement of such fluid-interaction systems. The NES has an essentially nonlinear cubic stiffness and a nonlinear cubic damping. Complexification-averaging and fourth-order Runge-Kutta methods are applied to solve the equations of the motion. The conditions of flow-induced instability, the weak modulated response (WMR), and the strongly modulated response (SMR) are investigated. The influence of the internal fluid velocity, the external flow velocity, the viscoelastic damping coefficient, the NES stiffness, location, and damping on the system efficiency is elucidated. The Poincare-Bendixson theorem implies that there are no closed trajectories in the phase diagram of the system response. The results revealed that the occurrence probability of the SMR and jump phenomenon in the system response increases by ascending the internal fluid velocity. Besides, it is shown that at high external fluid velocities or low viscoelastic damping coefficients, the detached resonance curve (DRC) emerges in the frequency-response curves, and simultaneously the unstable regions expand. Furthermore, by approaching the NES installation location to the pipe supports, the occurrence probability of the SMR, DRC, and WMR descends, the divergence regions are enlarged and the transient response lasts longer.

在本文中，研究了粘弹性管输送流体的动力学特性，该粘弹性管附接到正弦流下的非线性能量吸收器（NES），旨在改善此类流体相互作用系统的性能。NES具有基本非线性的立方刚度和非线性的立方阻尼。应用复数平均和四阶Runge-Kutta方法求解运动方程。研究了流动引起的不稳定性，弱调制响应（WMR）和强调制响应（SMR）的条件。阐明了内部流体速度，外部流速，粘弹性阻尼系数，NES刚度，位置和阻尼对系统效率的影响。Poincare-Bendixson定理表明，系统响应的相图中没有闭合轨迹。结果表明，随着内部流体速度的增加，系统响应中SMR的发生概率和跳跃现象增加。此外，还表明，在较高的外部流体速度或较低的粘弹性阻尼系数下，在频率响应曲线中会出现分离的共振曲线（DRC），同时不稳定区域也会扩展。此外，通过将NES安装位置靠近管道支架，SMR，DRC和WMR的出现概率降低，发散区域扩大，瞬态响应持续更长的时间。结果表明，随着内部流体速度的增加，系统响应中SMR的发生概率和跳跃现象增加。此外，还表明，在较高的外部流体速度或较低的粘弹性阻尼系数下，在频率响应曲线中会出现分离的共振曲线（DRC），同时不稳定区域也会扩展。此外，通过将NES安装位置靠近管道支架，SMR，DRC和WMR的出现概率降低，发散区域扩大，瞬态响应持续更长的时间。结果表明，随着内部流体速度的增加，系统响应中SMR的发生概率和跳跃现象增加。此外，还表明，在较高的外部流体速度或较低的粘弹性阻尼系数下，在频率响应曲线中会出现分离的共振曲线（DRC），同时不稳定区域也会扩展。此外，通过将NES安装位置靠近管道支架，SMR，DRC和WMR的出现概率降低，发散区域扩大，瞬态响应持续更长的时间。同时不稳定区域也在扩大。此外，通过将NES安装位置靠近管道支架，SMR，DRC和WMR的出现概率降低，发散区域扩大，瞬态响应持续更长的时间。同时不稳定区域也在扩大。此外，通过将NES安装位置靠近管道支架，SMR，DRC和WMR的出现概率降低，发散区域扩大，瞬态响应持续更长的时间。