Natural frequency assignment of a pipeline through structural modification in layout optimization of elastic supports

Abstract

Layout optimization of elastic supports is an effective approach to address the resonance problem of an industrial post-manufactured pipeline. However, previous investigations of support layout optimization of a post-manufactured pipeline usually require establishing or updating the numerical model of the whole pipeline system, which may lead to time-consuming calculations and poor optimization results. In order to overcome these drawbacks, a new measurement-based layout optimization method is proposed in this method. Only a small number of experimental modal parameters (natural frequencies, damping ratios, and mode shapes) are needed in this method. Resonance avoidance, in this method, is recast as an assignment of natural frequencies, and the target natural frequencies are realized by performing structural modification in two stages. In addition, each of the elastic supports is viewed as a mass-spring-damper sub-system in this paper, which is represented by its measured dynamic stiffness and does not need a pre-determined simplified form. A numerical example demonstrates that the proposed method can accurately realize the target natural frequencies. The application of the proposed method to optimize the support layout of a real L-shaped pipeline system provides experimental evidence of its effectiveness. This experiment is the first attempt to achieve the layout optimization of pipeline supports for solving the resonance problem of a post-manufacture pipeline, entirely relying on the measured modal data.