Identification method of distributed flow-induced loads on pipeline based on Chebyshev orthogonal polynomials and variational mode decomposition

The frequency-domain load identification method is effective in investigating an approach to the excitation characteristics of flow-induced loads with harmonic and broadband components on a fluid-conveying pipeline. However, the current frequency-domain load identification methods commonly encounter spurious peaks at the natural frequencies, making it difficult to obtain accurate distributed flow-induced loads. Hence, a highly accurate identification method of distributed flow-induced loads on a pipeline is established in this study based on Chebyshev orthogonal polynomials and variational modal decomposition technology. The flow-induced loads are characterized as a linear superposition of generalized Chebyshev orthogonal polynomials, and then the distributed load identification problem is recast as solving for the coefficients of Chebyshev polynomials, which can be obtained through the measured vibration response at a small number of measurement points. The spurious peaks in coefficients of Chebyshev polynomials are eliminated easily by variational modal decomposition technology, allowing for the accurate distributed flow-induced loads. A numerical example demonstrates that the proposed method can accurately identify distributed loads with both harmonic and broadband components. The effectiveness of the proposed method is validated experimentally by applying it to identify the flow-induced loads of a real pump-pipeline system. This experiment is the first attempt to obtain the distributed flow-induced loads with harmonic and broadband components of a pump-pipeline system. • A highly-accurate flow-induced load identification method based on Chebyshev orthogonal polynomials and VMD is proposed. • This method can suppress the spurious peaks at the natural frequencies, improving the accuracy of the identified loads. • Only the vibration response of a small number of measurement points needs to be measured in this method. • It is the first study on the vibration excitation characteristics of the flow-induced load in a real pump-pipeline system.