Detection of damage in welded joints using high order feature guided ultrasonic waves

Research into the use of nonlinear ultrasonic guided waves for nondestructive evaluation is expanding at a high rate because of the great potential benefit that they possess for early detection of material degradation. However, development of inspection and testing strategies is complicated because (i) the underlying physical principles are complex, (ii) there is a broad spectrum of possible solutions but only a limited number that have been shown to be effective, and (iii) the nonlinearity is weak and thus its measurement is challenging. This Tutorial aims to provide a foundation for researchers and technology-transitioners alike, to advance the application of nonlinear ultrasonic guided waves and ultimately transform how the service lives of structural systems are managed. The Tutorial focuses on the physical principles of nonlinear ultrasonic guided waves leading to the so-called internal resonance conditions that provide a means for selecting primary waves that generate cumulative secondary waves. To detect material degradation, we are primarily interested in nonlinearity stemming from the material itself, which is represented as hyperelastic. For the special case of plates, internal resonance points have been identified and case studies are presented to illustrate some of the applications. The Tutorial has one new result not published in a research paper; finite element simulation of energy transfer from shear-horizontal primary waves to symmetric Lamb waves at the second harmonic.

Nonlinear ultrasonic guided waves—Principles for nondestructive evaluation

Multi-mode reverse time migration damage imaging using ultrasonic guided waves.

In this work, we analyze theoretically and observe experimentally the frequency mixing response induced by the collinear interaction of two primary Lamb waves with different frequencies in an isotropic and homogenous plate The internal resonance conditions for generating the combined harmonics are analyzed by using a perturbation approach and a normal-mode-expansion technique for waveguide excitation The second- and third-order combined harmonics generated by the collinear wave mixing of two primary Lamb waves propagating in a specimen are analyzed, and the existence of the combined harmonics at specific frequencies is predicted An experimental procedure is proposed to measure the combined harmonics induced by the collinear cross-interaction of the two specific primary Lamb waves at given frequencies The theoretical prediction of the appearance of the combined harmonics at the specific mixing frequencies is consistent with experiment The theoretical analysis and experimental observation provide a clear physical insight into the frequency-mixing response induced by the collinear cross-interaction of two primary ultrasonic Lamb waves

Theoretical analysis and experimental observation of frequency mixing response of ultrasonic Lamb waves

Mixing of ultrasonic Lamb waves in thin plates with quadratic nonlinearity.

Nonlinear ultrasonic Lamb waves are popular to characterize the nonlinearity of materials. However, the widely used nonlinear Lamb mode suffers from two associated complications: inherent dispersive and multimode natures. To overcome these, the symmetric Lamb mode (S0) at low frequency region is explored. At the low frequency region, the S0 mode is little dispersive and easy to generate. However, the secondary mode still exists, and increases linearly for significant distance. Numerical simulations and experiments are used to validate the nonlinear features and therefore demonstrate an easy alternative for nonlinear Lamb wave applications.

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Numerical and experimental investigation of nonlinear ultrasonic Lamb waves at low frequency

Guided waves are attractive for long range inspections from a single generation position. However when the waveguide is embedded in another medium, the energy of the guided waves may leak into the surrounding material, causing significant reduction of the inspection distance. A number of analytical or numerical models were developed to understand the behavior of guided waves in embedded waveguides, among which one of the attractive methods was to combine the Semi-Analytical Finite Element (SAFE) method with Perfectly Matched Layer (PML). This paper presents a development to implement the SAFE-PML model in a commercially available Finite Element package. As no source code is required, the presented method will be attractive to a wide range of researchers in Non-Destructive Evaluation (NDE). The model is first demonstrated and validated in two cases with analytical solutions. Discussions have been carried out regarding the procedure to select proper modeling parameters. The potential of the model is also illustrated on an important application of guided waves along embedded pipelines.

Numerical modeling of embedded solid waveguides using SAFE-PML approach using a commercially available finite element package

SAFE-PML approach for modal study of waveguides with arbitrary cross sections immersed in inviscid fluid

Nonlinear guided waves have been investigated widely in simple geometries, such as plates, pipe and shells, where analytical solutions have been developed. This paper extends the application of nonlinear guided waves to waveguides with arbitrary cross sections. The criteria for the existence of nonlinear guided waves were summarized based on the finite deformation theory and nonlinear material properties. Numerical models were developed for the analysis of nonlinear guided waves in complex geometries, including nonlinear Semi-Analytical Finite Element (SAFE) method to identify internal resonant modes in complex waveguides, and Finite Element (FE) models to simulate the nonlinear wave propagation at resonant frequencies. Two examples, an aluminum plate and a steel rectangular bar, were studied using the proposed numerical model, demonstrating the existence of nonlinear guided waves in such structures and the energy transfer from primary to secondary modes.

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Peng Zuo

Papers

Numerical and experimental investigation of nonlinear ultrasonic Lamb waves at low frequency

Detection of damage in welded joints using high order feature guided ultrasonic waves

Numerical modeling of embedded solid waveguides using SAFE-PML approach using a commercially available finite element package

SAFE-PML approach for modal study of waveguides with arbitrary cross sections immersed in inviscid fluid

Numerical studies of nonlinear ultrasonic guided waves in uniform waveguides with arbitrary cross sections