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Ultrasonic guided waves in elliptical annular cylinders
Prabhu Rajagopal1, Roson Kumar Pattanayak1
1Centre for Nondestructive Evaluation, Department of Mechanical Engineering, Indian Institute of Technology Madras, Chennai 600036, Tamil Nadu, India prajagopal@iitm.ac.in, roson.pattanayak@gmail.com.
The Journal of the Acoustical Society of America
|October 3, 2015
Summary
Pipe ovalness significantly impacts guided wave modes used in inspections. Even slight ellipticity affects the L(0,2) and T(0,1) modes, crucial for assessing pipe integrity.
Area of Science:
- Solid Mechanics
- Acoustics
- Non-Destructive Testing
Background:
- Guided waves are essential for inspecting pipelines.
- Axisymmetric modes like L(0,2) and T(0,1) are commonly used.
- Pipe cross-section ovalness can influence wave propagation.
Purpose of the Study:
- To investigate the effect of cross-section ovalness on lower-order axisymmetric guided wave modes.
- To analyze the impact on the L(0,2) longitudinal mode and T(0,1) torsional mode.
- To assess the relevance of these effects for practical pipe inspection.
Main Methods:
- Utilized the semi-analytical finite element (FE) method as the primary analysis tool.
- Employed three-dimensional FE simulations for result visualization and validation.
- Studied thin pipe models with varying degrees of ovalness.
Main Results:
- Even minor ovalness in pipe cross-sections demonstrably alters guided wave mode shapes and velocities.
- The L(0,2) longitudinal mode is more sensitive to ovalness than the T(0,1) torsional mode.
- Observed changes in mode characteristics are significant enough to impact inspection interpretations.
Conclusions:
- Cross-section ovalness is a critical factor affecting the accuracy of guided wave-based pipe inspections.
- The pronounced effect on the L(0,2) mode necessitates careful consideration during data analysis.
- Findings highlight the importance of accounting for geometric imperfections in guided wave propagation models.
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