document

Localisation in a Cosserat continuum under static and dynamic loading conditions

De Borst, R. (author), Sluys, L.J. (author)

journal article 1991

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Wave propagation and localization in a rate-dependent cracked medium-model formulation and one-dimensional examples

Sluys, L.J. (author), De Borst, R. (author)

journal article 1992

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Wave propagation, localization and dispersion in a gradient-dependent medium

Sluys, L.J. (author), De Borst, R. (author), Muhlhaus, H.B. (author)

journal article 1993

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Fundamental issues in finite element analyses of localization of deformation

De Borst, R. (author), Sluys, L.J. (author), Muhlhaus, H.B. (author), Pamin, J. (author)

journal article 1993

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Some observations on localisation in non-local and gradient damage models

Peerlings, R.H.J. (author), De Borst, R. (author), Brekelmans, W.A.M. (author), De Vree, J.H.P. (author), Spee, I. (author)

journal article 1996

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Comparison of Eigenvectors for Coupled Seismo-Electromagnetic Layered-Earth Modeling

Grobbe, N. (author), Slob, E.C. (author), Thorbecke, J.W. (author)

We study the accuracy and numerical stability of three eigenvector sets for modelling the coupled poroelastic and electromagnetic layered-Earth response. We use a known eigenvector set, its flux-normalized version and a newly derived flux-normalized set. The new set is chosen such that the system is properly uncoupled when the coupling between...

journal article 2016

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Discretization effects in the finite element simulation of seismic waves in elastic and elastic-plastic media

Watanabe, Kohei (author), Pisano, F. (author), Jeremi, Boris (author)

Presented here is a numerical investigation that (re-)appraises standard rules for space/time discretization in seismic wave propagation analyses. Although the issue is almost off the table of research, situations are often encountered where (established) discretization criteria are not observed and inaccurate results possibly obtained. In...

journal article 2016

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Two-receiver measurements of phase velocity: cross-validation of ambient-noise and earthquake-based observations

Kästle, Emanuel D. (author), Soomro, Riaz (author), Weemstra, C. (author), Boschi, Lapo (author), Meier, Thomas (author)

Phase velocities derived from ambient-noise cross-correlation are compared with phase velocities calculated from cross-correlations of waveform recordings of teleseismic earthquakes whose epicentres are approximately on the station–station great circle. The comparison is conducted both for Rayleigh and Love waves using over 1000 station pairs in...

journal article 2016

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Combination of surface and borehole seismic data for robust target-oriented imaging

Liu, Yi (author), van der Neut, J.R. (author), Arntsen, B (author), Wapenaar, C.P.A. (author)

A novel application of seismic interferometry (SI) and Marchenko imaging using both surface and borehole data is presented. A series of redatuming schemes is proposed to combine both data sets for robust deep local imaging in the presence of velocity uncertainties. The redatuming schemes create a virtual acquisition geometry where both sources...

journal article 2016

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Efficient and accurate PLIC-VOF techniques for numerical simulations of free surface water waves

Duz, B. (author), Borsboom, M.J.A. (author), Veldman, A.E.P. (author), Wellens, P.R. (author), Huijsmans, R.H.M. (author)

In this paper the attention is focused on the effect of various VOF methods on efficient and accurate simulation of free surface water waves. For this purpose, we will compare several VOF methods in numerical simulations of propagating waves where strong nonlinear behavior is dominant in the flow. Comparisons and discussions will be provided to...

conference paper 2016

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Long-range correlations of microseism-band pressure fluctuations in the ocean

Ball, Justin S. (author), Godin, Oleg A. (author), Evers, L.G. (author), Lv, Cheng (author)

We investigate the spatial coherence of underwater ambient noise using a yearlong time-series measured off Ascension Island. Qualitative agreement with observed cross-correlations is achieved using a simple range-dependent model, constrained by earlier, active tomographic studies in the area. In particular, the model correctly predicts the...

journal article 2016

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Deep ocean sound speed characteristics passively derived from the ambient acoustic noise field

Evers, L.G. (author), Wapenaar, C.P.A. (author), Heaney, KD (author), Snellen, M. (author)

The propagation of acoustic waves in the ocean strongly depends on the temperature. Lowfrequency acoustic waves can penetrate the ocean down to depths where few in situ measurements are available. It is therefore attractive to obtain a measure of the deep ocean temperature from acoustic waves. The latter is especially true if the ambient...

journal article 2017

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Infrasound from the 2009 and 2017 DPRK rocket launches

Evers, L.G. (author), Assink, J. D. (author), Smets, P.S.M. (author)

Supersonic rockets generate low-frequency acoustic waves, that is, infrasound, during the launch and re-entry. Infrasound is routinely observed at infrasound arrays from the International Monitoring System, in place for the verification of the Comprehensive Nuclear-Test-Ban Treaty. Association and source identification are key elements of the...

journal article 2018

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Unified matrix-vector wave equation, reciprocity and representations

Wapenaar, C.P.A. (author)

The matrix-vector wave equation is a compact first-order differential equation. It was originally used for the analysis of elastodynamic plane waves in laterally invariant media. It has been extended by various authors for laterally varying media. Other authors derived a similar formalism for other wave phenomena. This paper starts with a...

journal article 2019

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Sensitivity analysis of generalised eigenproblems and application to wave and finite element models

Cicirello, A. (author), Mace, Brian (author), Kingan, Michael (author), Yang, Yi (author)

The first and second order sensitivity analysis of the eigenvalue problem of generalised, nonsymmetric matrices using perturbation theory is developed. These results are then applied to sensitivity analysis of wave propagation in structures modelled using the wave and finite element (WFE) method. Three formulations of the WFE eigenvalue problem...

journal article 2020

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Experiences with SWASH on modelling wave propagation over vegetation: Comparisons with lab and field data

Reis, Rui Almeida (author), Pires-Silva, António A. (author), Juana Fortes, Conceição (author), Suzuki, T. (author)

The vegetation capacity to protect the coasts from wave action is becoming more important and attractive due to ongoing sea level rise and increasing storminess. In addition, it is a quite environmentally friendly way. Quantifying the vegetation effect in wave propagation will be relevant for coastal management. A non-hydrostatic wave model...

journal article 2020

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Comparisons between beam and continuum models for modelling wheel-rail impact at a singular rail surface defect

Shen, C. (author), Deng, X. (author), Wei, Z. (author), Dollevoet, R.P.B.J. (author), Zoeteman, A. (author), Li, Z. (author)

A singular rail or wheel surface irregularity, such as a squat, insulation joint or wheel flat, can cause large wheelrail impact force. Both the magnitude and frequency content of the impact force need to be correctly modelledbecause they are closely related to the formation, deterioration and detection of such irregularities. In this paper,we...

journal article 2021

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Vibration modes and wave propagation of the rail under fastening constraint

Zhang, P. (author), Li, S. (author), Nunez, Alfredo (author), Li, Z. (author)

This paper investigates three-dimensional (3D) rail vibrations under fastening constraint up to 5000 Hz and provides insights into rail vibration control by fastening parameters. A methodology is proposed, including experimental investigation and numerical simulations of rail vibrations. Three steps are considered: 1) experimental investigation...

journal article 2021

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Ultrasonic propagation in liquid and ice water drops. Effect of porosity

Mendonck, Michiel (author), Aparicio, Sofía (author), Díaz, Cristóbal González (author), Hernández, Margarita G. (author), Caro, Guillermo M.Muñoz (author), Anaya, José Javier (author), Cazaux, S.M. (author)

This work studies ultrasonic propagation in liquid and ice water drops. The effect of porosity on attenuation of ultrasonic waves in the drops is also explored. The motivation of this research was the possible application of ultrasonic techniques to the study of interstellar and com-etary ice analogs. These ice analogs, made by vapor...

journal article 2021

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From wave speed to cardiac stiffness

Sabbadini, A. (author)

Diastolic heart failure is one of the principal causes of death in Western countries, and there is currently no treatment available; prevention, on the other hand, may be possible, provided an early enough diagnosis. The worsening of diastolic functionality is associated with increased values of cardiac stiffness, which could therefore provide a...

doctoral thesis 2021