Searched for: author:"Lourens, E."
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Petersen, W. (author), Øiseth, O. (author), Lourens, E. (author)
The traditional wind load assessment for long-span bridges relies on assumed models for the wind field and aerodynamic coefficients from wind tunnel tests, which usually introduce some uncertainties. Recent studies have shown that large deviations can exist between the predicted and observed wind-induced dynamic response of suspension bridges...
journal article 2020
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Skandali, D. (author), Lourens, E. (author), Ogink, R.H.M. (author)
A vessel's response to waves is dependent on a large number of parameters, some of which are both frequency and direction dependent. To predict vessel response, these parameters are used to construct response amplitude operators (RAOs) that act as transfer functions between the directional wave spectra and the motion spectra of the vessel. In...
journal article 2020
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Lourens, E. (author), Fallais, D.J.M. (author)
Kalman-type filters for coupled input-state estimation can be used to estimate the full-field dynamic response of structures from only a limited set of vibration measurements. The use of these coupled estimators allows for response prediction to be performed in the absence of any knowledge of both the dynamic evolution and spatial...
journal article 2019
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Petersen, Oyvind W. (author), Øiseth, Ole (author), Nord, Torodd Skjerve (author), Lourens, E. (author)
The traditional wind load assessment for long-span bridges rely on assumed models for the wind field and aerodynamic coefficients from wind tunnel tests, which usually introduces some uncertainties. It is therefore desired to develop tools that can utilize full-scale vibration response data from existing bridges in order to study the wind...
conference paper 2019
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Petersen, Øyvind Wiig (author), Øiseth, Ole (author), Lourens, E. (author)
The dynamic behaviour of long-span bridges is governed by stochastic loads from typically ambient excitation sources. In real life, these loads cannot be measured directly at full scale. However, inverse methods can be utilised to identify these unknown forces using response measurements together with a numerical model of the relevant...
journal article 2019
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Petersen, Oyvind W. (author), Øiseth, Ole (author), Nord, Torodd S. (author), Lourens, E. (author)
Numerical predictions of the dynamic response of complex structures are often uncertain due to uncertainties inherited from the assumed load effects. Inverse methods can estimate the true dynamic response of a structure through system inversion, combining measured acceleration data with a system model. This article presents a case study of...
journal article 2018
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Petersen, Øyvind Wiig (author), Øiseth, Ole (author), Lourens, E. (author)
Knowledge of the ambient loads are important for assessing the dynamic behavior of long-span bridges. However, the assumptions in the adopted load models used in the dynamic analysis leads to uncertainties in e.g. reliability assessments. To reduce the uncertainties, full-scale studies of the loads on existing structures can be performed....
conference paper 2018
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Petersen, Øyvind Wiig (author), Oiseth, Ole (author), Lourens, E. (author)
Structural health monitoring (SHM) seeks to assess the condition or behaviour of the structure from measurement data, which for long-span bridges typically are wind velocities and/or structural vibrations. However, in the assessment of the wind-induced response effects, models for the actual loads must be adopted, which introduces uncertainties....
journal article 2018
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Lourens, E. (author), Fallais, D.J.M. (author)
For the monitoring of large structures where the loading is typically characterized by large uncertainties in temporal and/or spatial evolution, algorithms capable of estimating a set of response driving equivalent forces are strongly desired. In this context, several Kalman-type coupled input-state and coupled input-state-parameter filters...
conference paper 2017
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de Oliveira Barbosa, J.M. (author), Qu, Y. (author), Metrikine, A. (author), Lourens, E. (author)
This work reports on experiments that were performed with a freely vibrating cylinder exposed to currents and placed near a plane boundary parallel to the cylinder axis. It is observed that the proximity of the boundary affects the vertical response of the cylinder in two ways: (i) for gaps between 0.75 and 2 diameters (D), the amplitude of...
journal article 2017
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Tsouvalas, A. (author), de Oliveira Barbosa, J.M. (author), Lourens, E. (author)
Earthquakes induced by the gas extraction is a problem of serious concern in the northern part of The Netherlands. The earthquakes recorded to date can be classified as minor based on their maximum local magnitude (ML=3.6). However, (i) their shallow focus, (ii) the special in-situ soft soil conditions and (iii) the fact the building stock in...
conference paper 2017
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Tatsis, K. (author), Chatzi, Efi (author), Thons, S. (author), Lourens, E. (author)
The evaluation of fatigue damage accumulation on wind turbine support structures under operational conditions is heavily influenced by a number of uncertainties. These uncertainties may, firstly, be attributed to the highly variable and complex environmental loads, and secondly, to the unavoidable modelling errors which mainly originate from the...
conference paper 2017
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Dostal, Leo (author), Lourens, E. (author), Metrikine, A. (author)
The problem of level ice interacting with compliant structures is addressed, where the ice loads can depend on the dynamical behavior of the structures. We are interested in a special type of ice-induced vibration, known as frequency lock-in, and characterized by having the dominant frequency of the ice forces near a natural frequency of the...
journal article 2017
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Nord, Torodd S. (author), Kvåle, Knut Andreas (author), Petersen, Oyvind W. (author), Bjerkås, Morten (author), Lourens, E. (author)
The sea ice interaction with a structure may cause system changes and affect the feasibility of common approaches to track modal parameters. In this paper, a covariance-driven stochastic subspace identification method is used to identify the natural frequencies from 190 time series of ice actions against a lighthouse structure. The results...
conference paper 2017
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Petersen, Øyvind Wiig (author), Øiseth, Ole (author), Lourens, E. (author)
Suspension bridges with very long spans and slender designs are susceptible to large-amplitude dynamic excitation. Monitoring systems installed on bridges can provide measurement data (e.g. accelerations) and therewith valuable information on the true dynamic behaviour. This pilot study examines the possible use of recently developed methods...
conference paper 2017
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Ravenshorst, G.J.P. (author), Esposito, R. (author), Schipper, H.R. (author), Messali, F. (author), Tsouvalas, A. (author), Lourens, E. (author), Rots, J.G. (author)
report 2016
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Tatsis, K. (author), Lourens, E. (author)
Quasi-periodic loading resulting from waves and a rotationally sampled wind field often leads to fatiguedriven designs for offshore wind turbine support structures. The uncertainty on wind and wave loading, together with large modelling uncertainties, lead to large discrepancies between the observed and predicted dynamic behaviour of these...
conference paper 2016
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Maes, K (author), de Roeck, G (author), Lombaert, G (author), van Nimmen, K (author), Lourens, E. (author), Rezayat, A (author), Guillaume, P (author)
This paper presents a verification of a state-of-the-art joint input-state estimation algorithm using data obtained from in situ experiments on a footbridge. A dynamic model of the footbridge is based on <br/>a detailed finite element model that is calibrated using a set of experimental modal characteristics. The joint input-state estimation...
conference paper 2016
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Petersen, Øyvind Wiig (author), Øiseth, Ole (author), Nord, Torodd Skjerve (author), Lourens, E. (author)
The Norwegian Public Roads Administration is reviewing the possibility of using floating bridges as fjord crossings. The dynamic behaviour of very long floating bridges with novel designs are prone to uncertainties. Studying the dynamic behaviour of existing bridges is valuable for understanding the in-situ performance. We present a case...
conference paper 2016
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Fallais, D.J.M. (author), Voormeeren, S.N. (author), Lourens, E. (author)
For reliable structural health monitoring and possible lifetime extension of offshore wind turbine support structures, accurate predictions of the response of these structures at all critical locations are required. Response predictions in offshore wind applications are, however, affected by large uncertainties on environmental (wind/wave...
journal article 2016
Searched for: author:"Lourens, E."
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