The Methodology for the Reliability Evaluation of the Signal Processing Methods Used for the Dispersion Estimation of Lamb Waves

Lina Draudvilieneand

doi:10.1109/tim.2021.3127625

Abstract

The applications of ultrasonic Lamb waves are becoming more and more frequent and diverse in industrial fields. These waves are used in non-destructive testing (NDT), structural health monitoring (SHM), for the assessment of the quality of materials, etc. However, due to the unusual properties of these waves, new or adapted signal processing methods are necessary to use for the analysis of such wave signals. Based on the requirements of ISO 17025, the work presents the methodology for verification of the signal processing methods used to reconstruct the dispersion curves of the phase and group velocities of Lamb waves. The key sequence of the mathematical and experimental stages, which must be passed to evaluate the reliability of the methods are developed. The present methodology includes the algorithm to optimally quantify the uncertainty, as to avoid additional testing, saving cost and time. The main characteristics and sources of the uncertainties, that mainly affect the accuracy of the obtained results are identified, analyzed, and presented. New standards for certification testing, inspection, and monitoring can be developed more easily and quickly based on the provided methodology in the future.

Highlights

NOWADAYS, the applications of the ultrasonic testing method based on Ultrasonic Lamb waves are becoming more diverse and increasingly employed
These waves are used in non-destructive testing (NDT), structural health monitoring (SHM), for the assessment of the quality of materials determining their elastic properties [1]-[7]
Obtained segments of the dispersion curves can be used to assess the uncertainty of the measurement model σ∆cmat (Table 1)

Summary

Introduction

NOWADAYS, the applications of the ultrasonic testing method based on Ultrasonic Lamb waves are becoming more diverse and increasingly employed. Velocity as a function of frequency determines the occurrence of two - phase and group velocities and characterized by dispersion curves [13]-[15] These identified behavioral features suggest that the signal processing methods, commonly used for analysis of ultrasonic waves, cannot be employed for these waves. It is pertinent to perform a feasibility study after some new processing algorithm and/or method is proposed and developed to determine the performance characteristics [21] Such tests should include a system accuracy, linearity, limited detection and other parameters. Research publications presenting novel signal processing methods for Lamb waves dispersion evaluation usually skips reliability topic. Most often phrases such as: 'a good agreement', 'a good

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Conclusion