Unveiling Turbulence-Induced Stress Dynamics in Dented Pipe Using Acoustic Emission and Time-Frequency Analysis

Area of Science:

• Mechanical Engineering
• Non-destructive Testing
• Fluid Dynamics

Background:

• Dents are common pipeline defects impacting structural integrity and flow.
• Conventional inspection methods struggle to extract meaningful data from acoustic emission (AE) signals in dented sections.

Purpose of the Study:

• To investigate turbulence occurrence in dented pipe sections using AE time-frequency analysis.
• To correlate AE signal characteristics with flow-induced turbulence and dent severity.
• To establish AE analysis as a reliable method for pipeline integrity assessment.

Main Methods:

• AE signals were recorded during flow loop tests on pipes with varying dent depths (0%, 5%, 15%, 30%).
• Time-frequency analysis, specifically the Morlet wavelet transform, was applied to AE signal segments.
• Computational fluid dynamics (CFD) simulations were used to validate turbulence detection via Reynolds numbers.

Main Results:

• Signal energy in AE responses increased progressively with dent depth.
• A strong correlation (R² > 0.9) was found between wavelet coefficient energy and Reynolds number across signal segments.
• The study achieved a maximum signal energy of 2.54 × 10^-08 μE²/Hz for the 30% dented pipe's end segment.

Conclusions:

• AE time-frequency analysis is a robust technique for identifying and characterizing dent-induced turbulence.
• This approach enhances the assessment of mechanical deformation effects on AE signals in pipelines.
• The findings support improved pipeline integrity monitoring and defect diagnosis.