Searched for: author:"Lourens, E."
(1 - 20 of 22)

Pages

document
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
document
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
document
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
document
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
document
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
document
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
document
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
document
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
document
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
document
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
document
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
document
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
document
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
document
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
a detailed finite element model that is calibrated using a set of experimental modal characteristics. The joint input-state estimation...
conference paper 2016
document
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
document
Van der Male, P. (author), Lourens, E. (author)
The design for fatigue for offshore wind turbine structures is characterized by uncertainty, resulting from both loading specifications and numerical modelling. At the same time, fatigue is a main design driver for this type of structures. This study presents a strategy to monitor the accumulated fatigue damage in real-time, employing a joint...
conference paper 2015
document
van der Male, P. (author), Lourens, E. (author)
Support structures of offshore wind turbines are prone to failure from fatigue damage. The design for fatigue requires accurate predictions of the environmental conditions and an adequate definition of the structural properties, valid for the entire design life-time. Estimates of the accumulated fatigue damage are, however, characterized by a...
conference paper 2015
document
Nord, T.S. (author), Lourens, E. (author), Oiseth, O. (author), Metrikine, A. (author)
The level-ice forces exerted on a scale model of a compliant bottom founded structure are identified from noncollocated strain and acceleration measurements by means of a joint input-state estimation algorithm. The identification is performed based on two different finite element models: one entirely based on the blueprints of the structure, and...
conference paper 2014
document
Maes, K. (author), Lourens, E. (author), Van Nimmen, K. (author), Reynders, E. (author), Van den Broeck, P. (author), Guillaume, P. (author), De Roeck, G. (author), Lombaert, G. (author)
An existing joint input-state estimation algorithm is extended for applications in structural dynamics. The estimation of the input and the system states is performed in a minimum-variance unbiased way, based on a limited number of response measurements and a system model. An additional method is proposed to identify the noise statistics, which...
conference paper 2013
document
Segeren, M.L.A. (author), Lourens, E. (author)
To circumvent current industry problems related to the settling of grouted connections, a steel-to-steel or slip joint connection is proposed for fitting a transition piece onto an installed monopile foundation. In the first part of this contribution, a simplified dynamic analysis of the installation of such a joint is considered. Assuming...
conference paper 2013
Searched for: author:"Lourens, E."
(1 - 20 of 22)

Pages