A time-domain finite element boundary integration method for ultrasonic nondestructive evaluation

Shi, Fan; Skelton, E. A.; Lowe, M. J. S.

doi:10.1109/tuffc.2014.006507

Cited by 10 publications

(7 citation statements)

References 18 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…We are now in a position to sidestep these limitations and perform highly accurate numerical simulations in three dimensions due to recent advances such as hybrid methods [13,14]. We have been motivated to explore the validity of Kirchhoff theory in three dimensions as researchers developing modelling tools using three-dimensional (3D) KA for NDE in the power industry have observed significant differences of several dB between experimentally measured reflections from rough defects and KA simulations of the same cases [15].…”

Section: Introductionmentioning

confidence: 99%

The validity of Kirchhoff theory for scattering of elastic waves from rough surfaces

2015

View full text Add to dashboard Cite

The Kirchhoff approximation (KA) for elastic wave scattering from two-dimensional (2D) and three-dimensional (3D) rough surfaces is critically examined using finite-element (FE) simulations capable of extracting highly accurate data while retaining a fine-scale rough surface. The FE approach efficiently couples a time domain FE solver with a boundary integration method to compute the scattered signals from specific realizations of rough surfaces. Multiple random rough surfaces whose profiles have Gaussian statistics are studied by both Kirchhoff and FE models and the results are compared; Monte Carlo simulations are used to assess the comparison statistically. The comparison focuses on the averaged peak amplitude of the scattered signals, as it is an important characteristic measured in experiments. Comparisons, in both two dimensions and three dimensions, determine the accuracy of Kirchhoff theory in terms of an empirically estimated parameter σ 2 /λ 0 ( σ is the RMS value, and λ 0 is the correlation length, of the roughness), being considered accurate when this is less than some upper bound c , ( σ 2 /λ 0 < c ). The incidence and scattering angles also play important roles in the validity of the Kirchhoff theory and it is found that for modest incidence angles of less than 30°, the accuracy of the KA is improved even when σ 2 /λ 0 > c . In addition, the evaluation results are compared using 3D isotropic rough surfaces and 2D surfaces with the same surface parameters.

show abstract

Section: Introductionmentioning

confidence: 99%

The validity of Kirchhoff theory for scattering of elastic waves from rough surfaces

2015

View full text Add to dashboard Cite

show abstract

“…To model the diffuse scattering from rough boundaries, it has been necessary to utilize sophisticated numerical techniques that have been developed recently, 55 based around the finite-element (FE) method Pettit et al (2015); Shi et al (2014), the Green's function method Zhao and Freund (2009), and molecular dynamic model Liang et al (2014). These numerical methods require considerable computation resources and it is not easy to generalize conclusions of how the surface statistics affect the scattering beyond the specific cases simulated un-60 less the statistics are gathered from many multiples of such simulations.…”

mentioning

confidence: 99%

“…For each realization of the surface a purely numerical method, the finite element boundary integral (FEBI) approach Shi et al (2015Shi et al ( , 2014, is performed to compute σ sc . The FEBI method is highly efficient as it computes the very local scattering field on the 190 interface using an explicit time domain FE scheme inside a small domain, and then performs a boundary integral to globally calculate the scattered waves.…”

mentioning

confidence: 99%

Diffusely scattered and transmitted elastic waves by random rough solid-solid interfaces using an elastodynamic Kirchhoff approximation

Shi

Lowe

2017

Phys. Rev. B

Self Cite

View full text Add to dashboard Cite

Elastic waves scattered by random rough interfaces separating two distinct media play an important role in modelling phonon scattering and impact upon thermal transport models, and are also integral to ultrasonic inspection. We introduce theoretical formulae for the diffuse field of elastic waves scattered by, and transmitted across, random rough solid-solid interfaces using the elastodynamic Kirchhoff Approximation (KA). The new formulae are validated by comparison with numerical Monte Carlo simulations, for a wide range of roughness (rms σ≤λ/3, correlation length λ 0 ≥ wavelength λ), demonstrating a significant improvement over the widely used small-perturbation approach which is valid only for surfaces with small rms values. Physical analysis using the theoretical formulae derived here demonstrates that increasing the rms value leads to a considerable change of the scattering patterns for each mode. The roughness has different effects on the reflection and the transmission, with a strong dependence on the material properties. In the special case of a perfect match of the wave speed of the two solid media, the transmission is the same as the case for a flat interface. We pay particular attention to scattering in the specular direction, often used as an observable quantity, in terms of the roughness parameters, showing a peak at an intermediate value of rms; this rms value coincides with that predicted by the Rayleigh parameter.

show abstract

“…Progress has been made in developing full-wave scattering models based on hybrid FEM techniques [1]. However, similar progress has not been achieved in developing boundary integral equation techniques, with the main problem being the large simulation time and memory requirement.…”

Section: Introductionmentioning

confidence: 99%

MLFMA-accelerated Nyström method for ultrasonic scattering - Numerical results and experimental validation

Gurrala

Downs

Chen

et al. 2018

AIP Conference Proceedings

View full text Add to dashboard Cite

Abstract. Full wave scattering models for ultrasonic waves are necessary for the accurate prediction of voltage signals received from complex defects/flaws in practical nondestructive evaluation (NDE) measurements. We propose the high-order Nyström method accelerated by the multilevel fast multipole algorithm (MLFMA) as an improvement to the state-of-theart full-wave scattering models that are based on boundary integral equations. We present numerical results demonstrating improvements in simulation time and memory requirement. Particularly, we demonstrate the need for higher order geometry and field approximation in modeling NDE measurements. Also, we illustrate the importance of full-wave scattering models using experimental pulse-echo data from a spherical inclusion in a solid, which cannot be modeled accurately by approximation-based scattering models such as the Kirchhoff approximation.

show abstract

A time-domain finite element boundary integration method for ultrasonic nondestructive evaluation

Cited by 10 publications

References 18 publications

The validity of Kirchhoff theory for scattering of elastic waves from rough surfaces

The validity of Kirchhoff theory for scattering of elastic waves from rough surfaces

Diffusely scattered and transmitted elastic waves by random rough solid-solid interfaces using an elastodynamic Kirchhoff approximation

MLFMA-accelerated Nyström method for ultrasonic scattering - Numerical results and experimental validation

Contact Info

Product

Resources

About