Searched for: author%3A%22Lourens%2C+E.%22
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Zou, Joanna (author), Lourens, E. (author), Cicirello, A. (author)
Virtual sensing techniques have gained traction in applications to the structural health monitoring of monopile-based offshore wind turbines, as the strain response below the mudline, which is a primary indicator of fatigue damage accumulation, is impractical to measure directly with physical instrumentation. The Gaussian process latent force...
journal article 2023
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Petersen, Oyvind W. (author), Øiseth, Ole (author), Lourens, E. (author)
An application of inverse force identification of wind loads on bridges is presented. This contribution explores the extension of latent force models (LFMs) in Kalman filters. Specifically, it is shown how LFMs can be enriched with environmental information from wind data in order to realistically reflect the underlying physics behind the wind...
conference paper 2022
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Petersen, W. (author), Øiseth, O. (author), Lourens, E. (author)
Wind loading is an essential aspect in the design and assessment of long-span bridges, but it is often not well-known and cannot be measured directly. Most structural health monitoring systems can easily measure structural responses at discrete locations using accelerometers. This data can be combined with reduced-order modal models in Kalman...
journal article 2022
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Zou, J. (author), Cicirello, A. (author), Iliopoulos, Alexandros (author), Lourens, E. (author)
Fatigue assessment in offshore wind turbine support structures requires the monitoring of strains below the mudline, where the highest bending moments occur. However, direct measurement of these strains is generally impractical. This paper presents the validation of a virtual sensing technique based on the Gaussian process latent force model...
conference paper 2022
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Bilbao Nieva, J.A. (author), Lourens, E. (author), Schulze- Bonhage, Andreas (author), Ziegler, Lisa (author)
Wind turbine towers are subjected to highly varying internal loads, characterized by large uncertainty. The uncertainty stems from many factors, including what the actual wind fields experienced over time will be, modeling uncertainties given the various operational states of the turbine with and without controller interaction, the influence of...
journal article 2022
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Kortendijk, C.N. (author), Besseling, Floris (author), Jolink, Chris (author), Lourens, E. (author)
When employing vibration-based damage detection methods for monitoring the structural health of bridges, it is often possible to increase damage feature sensitivity by focusing on local as opposed to global vibrations. This heightened sensitivity, however, comes at a cost: by moving towards the higher frequency ranges and more local behavior,...
conference paper 2021
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Tatsis, K. E. (author), Dertimanis, V. K. (author), Papadimitriou, C. (author), Lourens, E. (author), Chatzi, E. N. (author)
This paper presents a general framework for estimating the state and unknown inputs at the level of a system subdomain using a limited number of output measurements, enabling thus the component-based vibration monitoring or control and providing a novel approach to model updating and hybrid testing applications. Under the premise that the...
journal article 2021
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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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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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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), 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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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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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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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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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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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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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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