Distribution optimization of NES cells on pipes conveying fluid

Abstract

To control multi-mode nonlinear vibrations in fluid-conveying pipe systems subjected to fluid-structure interaction and external excitations, this paper proposes a synergistic vibration reduction strategy based on multiple nonlinear energy sink (NES) cells. By integrating Euler-Bernoulli beam theory with nonlinear dynamics, a fluid-structure interaction dynamic model incorporating multiple NES cells is established. The system response is analyzed using the Galerkin truncation method (GTM) and the harmonic balance method (HBM). To circumvent the high computational cost of traditional nonlinear dynamic optimization, a novel “modal contribution degree” (MCD) index is proposed. Combined with the particle swarm optimization (PSO) algorithm, this index quantifies the potential of NESs to capture energy from specific modes, thereby facilitating rapid optimization of their spatial layout. The results indicate that the optimized NES cells exhibit a spontaneous clustering characteristic towards modal antinodes, achieving efficient synergistic suppression of the first two vibration modes, with vibration reduction efficiencies exceeding 70 % and 60 %, respectively. Parametric analysis further confirms that the optimal NES configuration demonstrates excellent robustness against variations in fluid velocity and external excitation intensity. Notably, the proposed MCD strategy increases computational efficiency by four orders of magnitude compared to the traditional HBM approach while maintaining high accuracy, providing solid theoretical support for the multi-mode vibration control of fluid-conveying pipe systems.