Article
Engineering, Multidisciplinary
R. Sancho, V. Rey-de-Pedraza, P. Lafourcade, R. A. Lebensohn, J. Segurado
Summary: An FFT-based algorithm is proposed to simulate the propagation of elastic waves in heterogeneous domains. The method incorporates the application of Dirichlet boundary conditions and uses a stable beta-Newmark approach for time discretization. By solving the equilibrium equations in Fourier space and employing a preconditioned Krylov solver, the method achieves high accuracy and computational efficiency. Numerical examples demonstrate its effectiveness in simulating wave propagation in different mediums.
COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING
(2023)
Article
Computer Science, Interdisciplinary Applications
F. Assous, M. Lin
Summary: This paper proposes a new method to solve the inverse scattering problem in a non-homogeneous elastic medium using data recorded in an acoustic medium. By combining time-reversal and redatuming techniques, it is possible to reduce the size of the inspected medium and recover the properties of the scatterer, with relative insensitivity to noise in the data.
JOURNAL OF COMPUTATIONAL PHYSICS
(2021)
Article
Mathematics, Applied
Santanu Manna, Akash Kumar
Summary: This paper focuses on the surface wave field in functionally graded multi-layer transversely isotropic heterogeneous magneto-elastic reinforced media and explores the mechanical properties and wave scattering relation in such media. By applying Haskell's technique and finite difference technique, the wave scattering relation and group velocity, phase velocity in the media are obtained, indicating that these characteristics are influenced by factors such as heterogeneity, reinforcement, magneto-elastic coupling parameters, and stability ratio.
APPLIED MATHEMATICS AND COMPUTATION
(2021)
Article
Acoustics
Alistair S. Ferguson, Anthony J. Mulholland, Katherine M. M. Tant, Mohammud Foondun
Summary: This article investigates high frequency elastic wave propagation in layered materials with locally anisotropic layers. It is important for understanding ultrasonic non-destructive testing of carbon fiber reinforced polymer composites and polycrystalline materials. The study focuses on monochromatic shear waves in two-dimensional heterogenous media and examines the reflection and transmission at layer interfaces. Stochastic differential equations are derived for the wave amplitudes, resulting in a Fokker-Planck equation to analyze the probability distribution of transmission coefficients.
Article
Mathematics, Applied
Gabriel N. Gatica, Antonio Marquez, Salim Meddahi
Summary: The study introduces and analyzes a new mixed finite element method for the standard linear model in viscoelasticity, showing that the resulting variational formulation is well-posed and proving the convergence of a class of H(div)-conforming semi-discrete schemes. Additionally, the use of the Newmark trapezoidal rule results in a fully discrete scheme with established convergence results. Numerical examples are provided to demonstrate the method's performance.
Article
Computer Science, Interdisciplinary Applications
Dalibor Lukas, Joachim Schoberl
Summary: In this study, several lowest-order finite element approximations to the problem of elastodynamics of thin-walled structures were compared using dispersion analysis, showing alignment with theory with a sufficient number of layers. Additionally, novel anisotropic hexahedral tangential-displacement and normal-normal-stress continuous (TDNNS) mixed finite elements were presented for Hellinger-Reissner formulation of elastodynamics, demonstrating efficiency up to a certain frequency parameter despite a large amount of degrees of freedom.
MATHEMATICS AND COMPUTERS IN SIMULATION
(2021)
Article
Materials Science, Characterization & Testing
Xudong Niu, Jie Zhang, Anthony Croxford, Bruce Drinkwater
Summary: This study explores how to accurately simulate the elastodynamic scattering behavior of an arbitrary defect using finite element analysis. The method involves measuring the scattered wave field and decomposing it into multi-modal far-field scattering amplitudes to determine the angular order of scattering. The results show that this approach allows for more efficient modeling of guided wave scattering and contributes to a better understanding of experimental defect characterization.
NONDESTRUCTIVE TESTING AND EVALUATION
(2023)
Article
Engineering, Multidisciplinary
Stijn Francois, Heedong Goh, Loukas F. Kallivokas
Summary: This paper discusses a new CFS-PML formulation that avoids convolution evaluation and preserves the second-order temporal character of elastic waves. Numerical experiments demonstrate the effectiveness of the proposed method for wave simulation on unbounded domains, as well as long-time stability.
COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING
(2021)
Article
Engineering, Multidisciplinary
Yiran Wang, Eric Chung, Shubin Fu
Summary: In this paper, a local model reduction approach is proposed for subsurface flow problems in stochastic and highly heterogeneous media. The mixed generalized multiscale finite element method (MGMsFEM) is used for single-phase flow equation, while the mixed finite element method (MFEM) is used for two-phase flow equation. The proposed method shows high accuracy and efficiency in both 2D and 3D representative models.
COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING
(2023)
Article
Engineering, Multidisciplinary
Hajer Methenni, Alexandre Imperiale, Sebastien Imperiale
Summary: This study proposes a new implicit-explicit scheme for modeling wave propagation within thin structures using the time-domain finite element method. The proposed approach overcomes the limitation of standard explicit schemes by allowing a time marching algorithm with a time step independent of the plate thickness. The method is applicable to various materials and configurations.
INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING
(2023)
Article
Water Resources
Anthony Beaudoin, Ivan Colecchio, Alejandro Boschan
Summary: This study investigates solute transport in 3D binary isotropic samples and finds that the connectivity of the high conductivity facies directly affects the flow pathways and the transport properties of the system. The results show that as the percolation threshold is reached, fast flow pathways are formed, leading to a decrease in solute arrival time and an increase in longitudinal dispersivity.
ADVANCES IN WATER RESOURCES
(2023)
Article
Mathematics, Applied
Nawfel Benatia, Abdellah El Kacimi, Omar Laghrouche, Ahmed Ratnani
Summary: This paper presents a high-order finite element method for solving time-harmonic Maxwell short wave problems. The method incorporates enhanced basis functions and element-level static condensation to improve the conditioning and reduce memory requirements. Benchmark tests demonstrate the accuracy and efficiency of the proposed method.
JOURNAL OF SCIENTIFIC COMPUTING
(2023)
Article
Engineering, Geological
Maxime Lacour, Guillaume Bal, Norman Abrahamson
Summary: The method introduces new stochastic variables and orthogonal polynomials to dynamically propagate epistemic uncertainty in material properties into a finite-element system, resulting in a time-domain polynomial chaos representation of the entire finite-element solution.
INTERNATIONAL JOURNAL FOR NUMERICAL AND ANALYTICAL METHODS IN GEOMECHANICS
(2021)
Article
Engineering, Geological
Radu Popescu, Pradipta Chakrabortty
Summary: The natural spatial variability of soil properties affects the mechanical response of geotechnical structures and can deviate failure surfaces. For soil liquefaction induced by seismic activity, it has been found that greater excess pore water pressure is generated in soils with small-scale variability. This paper provides an explanation based on centrifuge experiments and numerical simulations, showing that partial drainage during earthquakes may trigger softening of dilative soils.
SOIL DYNAMICS AND EARTHQUAKE ENGINEERING
(2024)
Article
Acoustics
Khaled M. Ahmida
Summary: This paper analyzes the problem of low-frequency sound propagation in ducts with varying cross-sections and presents spectral finite element formulations for dynamic analysis using tapered spectral elements. These elements can be used in connected waveguides through dynamic stiffness relations. Linear and polynomial duct types are considered, and the shape functions of the elements are established along with dynamic stiffness matrices. The presented spectral approach accurately describes acoustic wave motion in any position along multiply connected duct waveguides within the one-dimensional plane-wave assumption. Experimental verification and comparison with 3-D finite element solutions support the derived expressions. Modeling varying cross-section duct waveguides can have an important role in the design of acoustic excitation devices and horn-type loudspeakers. The advantage of the presented formulations lies in their low computational cost compared to finite element approaches.
JOURNAL OF VIBRATION AND CONTROL
(2023)
Article
Instruments & Instrumentation
S. G. Haslinger, M. J. S. Lowe, R. Craster, P. Huthwaite, F. Shi
Summary: Planar defects occurring in industrial plant operation can impact non-destructive testing used for structural integrity management. While smooth defect modeling is mature, rough defects pose challenges. A new statistical model predicts significant increases in signal amplitude, providing valuable insights for inspection qualification, with rigorous validations conducted.
Article
Acoustics
M. Huang, G. Sha, P. Huthwaite, S. Rokhlin, M. J. S. Lowe
Summary: This study develops a second-order approximation model and a three-dimensional finite element model for calculating scattering-induced attenuation in elastic wave propagation in polycrystals. The FE and analytical models show quantitative agreement in different frequency regimes, with grain shape affecting attenuation as frequency increases and attenuation anisotropy intensifying.
JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA
(2021)
Article
Materials Science, Characterization & Testing
N. J. Shipway, P. Huthwaite, M. J. S. Lowe, T. J. Barden
Summary: This paper investigates the potential of using deep learning methods for automated defect detection in Fluorescent Penetrant Inspection. By training a ResNet34 and ResNet50 architecture, as well as a Random Forest, on a dataset obtained from titanium alloy test pieces, it was found that ResNet50 can detect 95% of defects with a false call rate of 0.07, outperforming the Random Forest method. Increasing the amount of data obtained from non-defective regions also significantly improves performance.
NDT & E INTERNATIONAL
(2021)
Article
Acoustics
Georgios Sarris, Stewart G. Haslinger, Peter Huthwaite, Peter B. Nagy, Michael J. S. Lowe
Summary: This study uses high-fidelity two-dimensional finite element modeling to validate existing predictions and provide a unified approach to studying the problem of Rayleigh wave scattering from rough surfaces. The results show good agreement between theory and finite element results in the Rayleigh and stochastic scattering regimes, with power relationships obtained through dimensional analysis and simulations in the geometric regime. The method used for deriving three-dimensional theory can be verified by the insights provided in this study.
JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA
(2021)
Article
Acoustics
Yuan Liu, Michal K. Kalkowski, Ming Huang, Michael J. S. Lowe, Vykintas Samaitis, Vaidotas Cicenas, Andreas Schumm
Summary: This paper investigates the potential of using attenuation measurements to assess the ultrasonic inspectability of coarse-grained components. Results show good agreement between experiments and simulations, with suggestions for the reasons for discrepancies. The study highlights the non-uniqueness of the relationship between log-normal grain size distribution parameters and attenuation.
Article
Materials Science, Characterization & Testing
Stewart G. Haslinger, Michael J. S. Lowe, Zhengjun Wang, Fan Shi
Summary: This article investigates the implementation of ToFD methods for sizing rough defects using a purely theoretical approach, and uses high-fidelity finite element modeling and stochastic Monte Carlo methods to provide physical and statistical insights on the dependence on incident beam angle and degree of roughness for planar defects. It explores the complexity of rough defects compared to smooth defects in ultrasonic ToFD techniques, and examines the effects of roughness on the accuracy of crack sizing with statistical analysis.
NDT & E INTERNATIONAL
(2021)
Article
Multidisciplinary Sciences
Ming Huang, Peter Huthwaite, Stanislav Rokhlin, Michael J. S. Lowe
Summary: This study investigates the scattering-induced elastic wave attenuation and phase velocity variation in three-dimensional untextured cubic polycrystals using the theoretical second-order approximation, Born approximation models, and the grain-scale finite-element model. The results show good agreement between the theoretical and finite-element models for materials with Zener anisotropy indices greater than 1. However, the agreement deteriorates as the anisotropy index increases. The finite-element model reveals strong scattering at low frequencies in strongly scattering materials that cannot be fully accounted for by the theoretical models. A semi-analytical model is proposed to address this issue and shows remarkable agreement with the finite-element model for all studied materials.
PROCEEDINGS OF THE ROYAL SOCIETY A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES
(2022)
Article
Chemistry, Analytical
Filip Szlaszynski, Michael J. S. Lowe, Peter Huthwaite
Summary: Detection and assessment of defects in inaccessible locations in pipelines are challenging for many industries. This paper proposes the use of Plane Wave Imaging (PWI) in guided wave testing (GWT) to improve defect characterization in nearby locations. Experimental and finite element studies show that PWI achieves superior resolution compared to other synthetic focusing imaging techniques. The study concludes that PWI is a more attractive choice for pipe GWT, offering good resolution and high signal-to-noise ratio (SNR).
Article
Multidisciplinary Sciences
Ming Huang, Stanislav I. Rokhlin, Michael J. S. Lowe
Summary: This paper evaluates the scattering theory of plane longitudinal wave propagation in untextured polycrystals using three-dimensional grain-scale finite-element simulations. Two approximate models are proposed to achieve more accurate calculations.
PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES
(2022)
Article
Acoustics
Evripides Georgiades, Michael J. S. Lowe, Richard V. Craster
Summary: Leaky waves are important for guiding waves along embedded structures. Mismatch in wavespeeds leads to energy leakage, attenuating the guided wave. Accurate identification of leaky wave solutions is crucial for non-destructive evaluation techniques. By improving spectral collocation method, leaky wave solutions can be efficiently determined.
JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA
(2022)
Article
Acoustics
Georgios Sarris, Stewart G. Haslinger, Peter Huthwaite, Michael J. S. Lowe
Summary: The reduction in propagation speed of ultrasonic waves when passing through a fatigue zone has been studied, showing that shear waves are more affected than longitudinal waves. In this study, we validate the increased sensitivity of shear waves to fatigue by measuring the change in propagation speed on flat geometries. Using EMATs, we demonstrate the possibility of fatigue damage inspection on inner surfaces of pressure-containing components in the nuclear power industry.
IEEE TRANSACTIONS ON ULTRASONICS FERROELECTRICS AND FREQUENCY CONTROL
(2023)
Article
Materials Science, Characterization & Testing
Georgios Sarris, Stewart G. Haslinger, Peter Huthwaite, Michael J. S. Lowe
Summary: Fatigue zones in materials can be detected using ultrasonic waves, but the small changes in average propagation speed across the full thickness make it difficult to correlate with specific fatigue states. In this study, Rayleigh waves were used to amplify the changes in speed and successfully assessed fatigue states. The use of a stiffness-reducing finite-element modelling technique also provided accurate predictions of wave speed reduction.
NDT & E INTERNATIONAL
(2023)
Article
Acoustics
Georgios Sarris, Stewart G. G. Haslinger, Peter Huthwaite, Peter B. B. Nagy, Michael J. S. Lowe
Summary: In this study, the phenomenon of Rayleigh wave attenuation due to surface roughness is investigated using finite element modeling. The results show good agreement between the finite element results and theory in different scattering regimes, and also extend the validity of the theory.
JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA
(2023)
Article
Chemistry, Multidisciplinary
Michal K. Kalkowski, Zoltan Bezi, Michael J. S. Lowe, Andreas Schumm, Bernadett Spisak, Szabolcs Szavai
Summary: The basic principle of ultrasound is to use the time of flight of a received echo to determine the location of a reflector. However, this principle may not hold true in austenitic welds due to differences in local sound velocity caused by large oriented austenitic grains. Scattering at grain boundaries further complicates the inspection process. Incorporating material information into imaging algorithms can improve image quality and aid interpretation.
APPLIED SCIENCES-BASEL
(2023)
Proceedings Paper
Acoustics
George West, Emma Harris, Michael Lowe, Jeff Bamber, Peter Huthwaite
Summary: The study tested the ability of the multi-band finite element method to simulate the frequency dependence of attenuation of ultrasound within soft tissue materials, and found that the calculated signal loss agreed with the measured signal loss within the simulation to a high degree, reproducing the input parameters accurately.
INTERNATIONAL ULTRASONICS SYMPOSIUM (IEEE IUS 2021)
(2021)