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.

Vibration analysis of combined functionally graded cylindrical-conical shells coupled with annular plates in thermal environment

Acoustoelastic guided waves in waveguides with arbitrary prestress

Modal properties of elastic surface waves in the presence of material anisotropy and prestress

Nonlinear ultrasonic guided waves have been investigated widely in closed waveguides such as plates, pipes, etc. However, the description of nonlinear ultrasonic guided waves remains challenging for open waveguides, as energy may leak into the surrounding medium. In this work, the properties of nonlinear ultrasonic guided waves in open waveguides are investigated. Mathematical framework is first established based on real reciprocity relation and modal expansion with perfectly matched layers. Numerical models are then implemented, including nonlinear semi-analytical finite element (SAFE) method to predict the properties of nonlinear ultrasonic guided waves, and time domain finite element models to simulate the nonlinear guided wave propagation and cross validate the predictions from the nonlinear SAFE method. Two examples, an aluminum plate attached to an elastomer and an aluminum plate with water loaded on one side, are studied to demonstrate the proposed methods and reveal some interesting phenomena that only exist in open waveguides. It is interesting to find out that the amplitude of the attenuated second harmonic wave in immersed waveguides can keep constant with propagation distance, only if the primary wave is non-leaky, which may bring potential non-destructive test applications for underwater inspections. Such a feature is validated by well-designed experiments in one-sidedly immersed plates.

Investigation of nonlinear ultrasonic guided waves in open waveguides based on perfectly matched layers.

This study presents a new meshfree approach for thermal vibration analysis of laminated composite cylindrical shell subject to arbitrary boundary conditions. The boundaries of laminated structures are constrained by artificial springs with variable stiffness. The spectro-geometric method (SGM) combined sine/consine functions containing circumferential wavenumber is employed to expand the displacement components of physical system. Following Reissner-Naghdi's thin shell theory, the Lagrangian energy functionals of the studied structure is derived, and the governing equation of laminated composite cylindrical shell under thermal environment is formulated with Rayleigh-Ritz method. After that, the convergence investigation and accuracy examination of the present method are both carried out by performing some numerical case studies. Finally, the effect of some crucial factors including temperature variable, boundary condition, length-radius ratio and laminated layers on the thermal vibration characteristics of laminated composite cylindrical shell are also studied. 

Peng Zuo

Papers

Vibration analysis of combined functionally graded cylindrical-conical shells coupled with annular plates in thermal environment

Acoustoelastic guided waves in waveguides with arbitrary prestress

Modal properties of elastic surface waves in the presence of material anisotropy and prestress

Investigation of nonlinear ultrasonic guided waves in open waveguides based on perfectly matched layers.

A new meshfree approach for vibration analysis of arbitrary restrained laminated composite cylindrical shell under thermal environment