280 results found
Zhang C, Huthwaite P, Lowe M, 2018, The application of the Factorization Method to the subsurface imaging of surface-breaking cracks, IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control, ISSN: 0885-3010
IEEE A common location for cracks to appear is at the surface of a component; at the near surface, many nondestructive evaluation (NDE) techniques are available to inspect for these, but at the far surface this is much more challenging. Ultrasonic imaging is proposed to enable far surface defect detection, location and characterisation. One specific challenge here is the presence of a strong reflection from the backwall, which can often mask the relatively small response from a defect. In this paper, the Factorization Method (FM) is explored for the application of subsurface imaging of the surface-breaking cracks. In this application, the component has two parallel surfaces, the crack is initiated from the far side and the phased array is attached on the near side. Ideally, the pure scattered field from a defect is needed for the correct estimation of the scatterer through the FM algorithm. However, the presence of the backwall will introduce a strong specular reflection into the measured data which should be removed before applying the FM algorithm. A novel subtraction method was developed to remove the backwall reflection. The performance of the FM algorithm and this subtraction method were tested with the simulated and experimental data. The experimental results showed a good consistency with the simulated results. It is shown that the FM algorithm can generate high quality images to provide a good detection of the crack and an accurate sizing of the crack length. The subtraction method was able to provide a good backwall reflection removal in the case of small cracks (1-3 wavelengths).
Egerton JS, Lowe MJS, Huthwaite P, et al., 2017, Ultrasonic attenuation and phase velocity of high-density polyethylene pipe material, JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA, Vol: 141, Pages: 1535-1545, ISSN: 0001-4966
Egerton JS, Lowe MJS, Huthwaite P, et al., 2017, A multiband approach for accurate numerical simulation of frequency dependent ultrasonic wave propagation in the time domain, JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA, Vol: 142, Pages: 1270-1280, ISSN: 0001-4966
Haith MI, Ewert U, Hohendorf S, et al., 2017, Radiographic modelling for NDE of subsea pipelines, NDT & E INTERNATIONAL, Vol: 86, Pages: 113-122, ISSN: 0963-8695
Haith MI, Huthwaite P, Lowe MJS, 2017, Defect characterisation from limited view pipeline radiography, NDT & E INTERNATIONAL, Vol: 86, Pages: 186-198, ISSN: 0963-8695
Quintanilla FH, Lowe MJS, Craster RV, 2017, The symmetry and coupling properties of solutions in general anisotropic multilayer waveguides, JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA, Vol: 141, Pages: 406-418, ISSN: 0001-4966
Shi F, Lowe M, Craster R, 2017, Diffusely scattered and transmitted elastic waves by random rough solid-solid interfaces using an elastodynamic Kirchhoff approximation, PHYSICAL REVIEW B, Vol: 95, ISSN: 2469-9950
Elastic waves scattered by random rough interfaces separating two distinct media play an important role in modeling phonon scattering and impact upon thermal transport models, and are also integral to ultrasonic inspection. We introduce theoretical formulas for the diffuse field of elastic waves scattered by, and transmitted across, random rough solid-solid interfaces using the elastodynamic Kirchhoff approximation. The new formulas are validated by comparison with numerical Monte Carlo simulations, for a wide range of roughness (rms σ≤λ/3, correlation length λ0≥ 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 formulas 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.
Shi F, Lowe MJS, Craster RV, 2017, Recovery of correlation function of internal random rough surfaces from diffusely scattered elastic waves, JOURNAL OF THE MECHANICS AND PHYSICS OF SOLIDS, Vol: 99, Pages: 483-494, ISSN: 0022-5096
Shi F, Lowe MJS, Skelton EA, et al., 2017, A time-domain finite element boundary integral approach for elastic wave scattering, Computational Mechanics, Pages: 1-13, ISSN: 0178-7675
© 2017 The Author(s) The response of complex scatterers, such as rough or branched cracks, to incident elastic waves is required in many areas of industrial importance such as those in non-destructive evaluation and related fields; we develop an approach to generate accurate and rapid simulations. To achieve this we develop, in the time domain, an implementation to efficiently couple the finite element (FE) method within a small local region, and the boundary integral (BI) globally. The FE explicit scheme is run in a local box to compute the surface displacement of the scatterer, by giving forcing signals to excitation nodes, which can lie on the scatterer itself. The required input forces on the excitation nodes are obtained with a reformulated FE equation, according to the incident displacement field. The surface displacements computed by the local FE are then projected, through time-domain BI formulae, to calculate the scattering signals with different modes. This new method yields huge improvements in the efficiency of FE simulations for scattering from complex scatterers. We present results using different shapes and boundary conditions, all simulated using this approach in both 2D and 3D, and then compare with full FE models and theoretical solutions to demonstrate the efficiency and accuracy of this numerical approach.
Van Pamel A, Sha G, Rokhlin SI, et al., 2017, Finite-element modelling of elastic wave propagation and scattering within heterogeneous media, PROCEEDINGS OF THE ROYAL SOCIETY A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES, Vol: 473, ISSN: 1364-5021
Choi W, Skelton EA, Pettit J, et al., 2016, A Generic Hybrid Model for the Simulation of Three-Dimensional Bulk Elastodynamics for Use in Nondestructive Evaluation, IEEE TRANSACTIONS ON ULTRASONICS FERROELECTRICS AND FREQUENCY CONTROL, Vol: 63, Pages: 726-736, ISSN: 0885-3010
Egerton JS, Lowe MJS, Halai HV, et al., 2016, Improved FE Simulation of Ultrasound in Plastics, 42nd Annual Review of Progress in Quantitative Nondestructive Evaluation (QNDE), Publisher: AMER INST PHYSICS, ISSN: 0094-243X
Haith MI, Ewert U, Hohendorf S, et al., 2016, Modelling Based Radiography for NDE of Subsea Pipelines, 42nd Annual Review of Progress in Quantitative Nondestructive Evaluation (QNDE), Publisher: AMER INST PHYSICS, ISSN: 0094-243X
Huthwaite P, Lowe M, Cawley P, 2016, Guided Wave Tomography Performance Analysis, 42nd Annual Review of Progress in Quantitative Nondestructive Evaluation (QNDE), Publisher: AMER INST PHYSICS, ISSN: 0094-243X
Leinov E, Lowe MJS, Cawley P, 2016, Ultrasonic isolation of buried pipes, JOURNAL OF SOUND AND VIBRATION, Vol: 363, Pages: 225-239, ISSN: 0022-460X
Leinov E, Lowe MJS, Cawley P, 2016, Investigation of guided wave propagation in pipes fully and partially embedded in concrete, JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA, Vol: 140, Pages: 4528-4539, ISSN: 0001-4966
Quintanilla FH, Lowe MJS, Craster RV, 2016, Full 3D dispersion curve solutions for guided waves in generally anisotropic media, JOURNAL OF SOUND AND VIBRATION, Vol: 363, Pages: 545-559, ISSN: 0022-460X
Seher M, Huthwaite P, Lowe MJS, 2016, Experimental Studies of the Inspection of Areas With Restricted Access Using A0 Lamb Wave Tomography, IEEE TRANSACTIONS ON ULTRASONICS FERROELECTRICS AND FREQUENCY CONTROL, Vol: 63, Pages: 1455-1467, ISSN: 0885-3010
Shi F, Lowe MJS, Xi X, et al., 2016, Diffuse scattered field of elastic waves from randomly rough surfaces using an analytical Kirchhoff theory, JOURNAL OF THE MECHANICS AND PHYSICS OF SOLIDS, Vol: 92, Pages: 260-277, ISSN: 0022-5096
Van Pamel A, Huthwaite P, Brett CR, et al., 2016, Numerical simulations of ultrasonic array imaging of highly scattering materials, NDT & E INTERNATIONAL, Vol: 81, Pages: 9-19, ISSN: 0963-8695
Van Pamel A, Nagy PB, Lowe MJS, 2016, On the dimensionality of elastic wave scattering within heterogeneous media, JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA, Vol: 140, Pages: 4360-4366, ISSN: 0001-4966
Ewert U, Tschaikner M, Hohendorf S, et al., 2015, Corrosion Monitoring with Tangential Radiography and Limited View Computed Tomography, 42nd Annual Review of Progress in Quantitative Nondestructive Evaluation (QNDE), Publisher: American Institute of Physics (AIP), ISSN: 1551-7616
Accurate and reliable detection of subsea pipeline corrosion is required in order to verify the integrity of the pipeline. A laboratory trial was conducted with a representative pipe sample. The accurate measurement of the wall thickness and corrosion was performed with high energy X-rays and a digital detector array. A 7.5 MV betatron was used to penetrate a stepped pipe and a welded test pipe of 3 m length and 327 mm outer diameter, with different artificial corrosion areas in the 24 mm thick steel wall. The radiographs were taken with a 40 x 40 cm² digital detector array, which was not large enough to cover the complete pipe diameter after magnification. A C-arm based geometry was tested to evaluate the potential for automated inspection in field. The primary goal was the accurate measurement of wall thickness conforming to the standard. The same geometry was used to explore the ability of a C-arm based scanner in asymmetric mode for computed tomography (CT) measurement, taking projections covering only two thirds of the pipe diameter. The technique was optimized with the modelling software aRTist. A full volume of the pipe was reconstructed and the CT data set was used for reverse engineering, providing a CAD file for further aRTist simulations to explore the technique for subsea inspections.
Fan Z, Mark AF, Lowe MJS, et al., 2015, Nonintrusive Estimation of Anisotropic Stiffness Maps of Heterogeneous Steel Welds for the Improvement of Ultrasonic Array Inspection, IEEE TRANSACTIONS ON ULTRASONICS FERROELECTRICS AND FREQUENCY CONTROL, Vol: 62, Pages: 1530-1543, ISSN: 0885-3010
Huthwaite P, Shi F, Van Pamel A, et al., 2015, High-Speed GPU-Based Finite Element Simulations for NDT, 41st Annual Review of Progress in Quantitative Nondestructive Evaluation (QNDE), Publisher: AMER INST PHYSICS, Pages: 1815-1819, ISSN: 0094-243X
Lan B, Lowe MJS, Dunne FPE, 2015, A spherical harmonic approach for the determination of HCP texture from ultrasound: A solution to the inverse problem, JOURNAL OF THE MECHANICS AND PHYSICS OF SOLIDS, Vol: 83, Pages: 179-198, ISSN: 0022-5096
Lan B, Lowe MJS, Dunne FPE, 2015, A generalized spherical harmonic deconvolution to obtain texture of cubic materials from ultrasonic wave speed, JOURNAL OF THE MECHANICS AND PHYSICS OF SOLIDS, Vol: 83, Pages: 221-242, ISSN: 0022-5096
Leinov E, Cawley P, Lowe MJS, 2015, Guided Wave Attenuation in Pipes Buried in Sand, 41st Annual Review of Progress in Quantitative Nondestructive Evaluation (QNDE), Publisher: AMER INST PHYSICS, Pages: 227-236, ISSN: 0094-243X
Leinov E, Cawley P, Lowe MJS, 2015, Guided Wave Attenuation in Coated Pipes Buried in Sand, 42nd Annual Review of Progress in Quantitative Nondestructive Evaluation (QNDE), Publisher: American Institute of Physics (AIP), ISSN: 1551-7616
Long-range guided wave testing (GWT) is routinely used for the monitoring and detection of corrosion defects in above ground pipelines in various industries. The GWT test range in buried, coated pipelines is greatly reduced compared to aboveground pipelines due to energy leakage into the embedding soil. In this study, we aim to increase test ranges for buried pipelines. The effect of pipe coatings on the T(0,1) and L(0,2) guided wave attenuation is investigated using a full-scale experimental apparatus and model predictions. Tests are performed on a fusion-bonded epoxy (FBE)-coated 8” pipe, buried in loose and compacted sand over a frequency range of 10-35 kHz. The application of a low impedance coating is shown to effectively decouple the influence of the sand on the ultrasound leakage from the buried pipe. We demonstrate ultrasonic isolation of a buried pipe by coating the pipe with a Polyethylene (PE)-foam layer that has a smaller impedance than both pipe and sand and the ability to withstand the overburden load from the sand. The measured attenuation in the buried PE-foam-FBE-coated pipe is substantially reduced, in the range of 0.3-1.2 dBm−1 for loose and compacted sand conditions, compared to buried FBE-coated pipe without the PE-foam, where the measured attenuation is in the range of 1.7-4.7 dBm−1. The acoustic properties of the PE-foam are measured independently using ultrasonic interferometry technique and used in model predictions of guided wave propagation in a buried coated pipe. Good agreement is found between the attenuation measurements and model predictions. The attenuation exhibits periodic peaks in the frequency domain corresponding to the through-thickness resonance frequencies of the coating layer. The large reduction in guided wave attenuation for PE-coated pipes would lead to greatly increased GWT test ranges, so such coatings would be attractive for new pipeline installations.
Leinov E, Lowe MJS, Cawley P, 2015, Investigation of guided wave propagation and attenuation in pipe buried in sand, JOURNAL OF SOUND AND VIBRATION, Vol: 347, Pages: 96-114, ISSN: 0022-460X
Pettit JR, Walker AE, Lowe MJS, 2015, Modelling NDE Pulse-Echo inspection Of Misorientated Planar Rough Defects Using An Elastic Finite Element Method, 41st Annual Review of Progress in Quantitative Nondestructive Evaluation (QNDE), Publisher: AMER INST PHYSICS, Pages: 1730-1737, ISSN: 0094-243X
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