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Scattering of guided waves propagating through pipe bends based on normal mode expansion
Wenjun Wu1, Hao Dong2, Shangyu Zhang3
1School of Naval Architecture, Ocean and Energy Power Engineering, Wuhan University of Technology, Wuhan, 430063, China. wuweju@126.com.
Scientific Reports
|July 21, 2022
Summary
This study analyzes guided wave scattering in pipe bends using normal mode expansion. It identifies key mode conversions, like L(0,1) reflection and conversion to F(1,1), validated by simulations and experiments.
Area of Science:
- Acoustics
- Mechanical Engineering
- Materials Science
Background:
- Guided waves in pipes are crucial for structural health monitoring and non-destructive testing.
- Pipe bends introduce complex scattering phenomena that alter wave propagation.
- Understanding mode conversions is essential for accurate signal interpretation.
Purpose of the Study:
- To investigate the scattering of guided waves in pipe bends.
- To develop a theoretical framework for predicting mode conversions at bends.
- To validate theoretical predictions with numerical simulations and experimental data.
Main Methods:
- Derivation of the bi-orthogonality relationship for normal modes in pipe bends.
- Expansion of displacement and stress fields using normal modes at interfaces.
- Formulation of the scattering problem as an eigenproblem of a transfer matrix.
Main Results:
- The study predicts dominant mode conversions for a low-frequency longitudinal mode incident on a pipe bend.
- Key conversions identified include L(0,1) reflection and mode conversion from L(0,1) to F(1,1).
- Theoretical predictions show excellent agreement with finite element simulations and experimental observations.
Conclusions:
- Normal mode expansion effectively analyzes guided wave scattering in pipe bends.
- The transfer matrix method accurately predicts mode conversions at pipe bends.
- Experimental validation confirms the theoretical model's reliability for analyzing wave propagation in complex geometries.
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