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Logo: ISD/Leibniz Universität Hannover
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Logo: ISD/Leibniz Universität Hannover
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Current Research Projects

Well-founded meta-modeling of wind turbines as an example of stochastic, controlled structures (MetaWind)

 

Supervisor:

Dr.-Ing. Clemens Hübler

Researcher:

Franziska Müller, M.Sc.

Duration:

2019- 2021

Funded by:

Leibniz Young Investigator Grant (LUH)

Brief description:

Smart systems, which mostly come from the field of communication technology and consist of a combination of networked, controllable, sensory and intelligent subsystems, have been omnipresent in media in recent years. Smart systems have actually been around for years in a wide variety of engineering fields. In civil engineering, an example are wind turbines with networked elements of measurement and control technology. For an economical and reliable design of these systems, their simulation is necessary. Due to the non-linear, stochastic, and controlled behaviour of such systems, the required computing time can be uneconomically high. In this case, substitute models, so-called meta-models, can be used to approximate the system behaviour. Although meta-models are already widely used today, their accuracy and efficiency are limited so far. Comprehensive analyses for complex systems are scarce. Therefore, MetaWind addresses this research gap and develops well-founded meta-models for wind turbines based on a comprehensive comparison of different variants.

 

 

Efficient modelling of wind turbines in time-domain considering uncertain parameters (ENERGIZE)

Bild zum Projekt Effizienzsteigerung unscharfer Strukturanalysen von Windenergieanlagen im Zeitbereich (ENERGIZE)

Supervisor:

Prof. Dr.-Ing. habil. Raimund Rolfes, Dr.-Ing. Cristian Gebhardt

Researcher:

Dr.-Ing. Clemens Hübler

Duration:

2019 – 2022

Funded by:

Deutsche Forschungsgemeinschaft (DFG)

Brief description:

Wind energy is a promising technology to achieve the objectives set for the development of renewable energy. To increase competitiveness, costs have to be reduced and the structural reliability has to be improved. A promising approach are more realistic simulations of wind turbines by considering polymorphic uncertainty. In this context, uncertainty is, for example, variability, incompleteness, and inaccuracy of data. Polymorphic uncertainty can be modelled by using imprecise probability. In research, for classical applications of civil engineering, imprecise probability becomes increasingly popular in recent years. However, for wind turbine applications, there are no approaches that use imprecise probability. The main reason is the complexity of wind turbines that combine challenges regarding uncertain and scattering inputs (typical for civil engineering) and complex controller actions (typical for mechanical and electrical engineering). This complexity leads to high computing times and hinders accurate meta-modelling, that is normally used, if computing times are not manageable. That is why in this project, at first, adequate imprecise probability methods are applied to wind turbine models. Subsequently, the efficiency of the uncertain analysis is increased by reducing the required number of model evaluations. This is the core of this project. First, the increase in efficiency is achieved by using enhanced sensitivity analyses, which can be applied when imprecise probability is utilised. By means of sensitivity analyses, the number of uncertain parameters can be reduced. Second, sampling techniques are developed, which can be combined with imprecise probabilities and load extrapolations for wind turbine fatigue loads. This enables an efficient modelling of complex wind turbines using polymorphic uncertain data. At the same time, computing times are kept manageable. Hence, more realistic simulations are possible.

 

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Optimierung der Bemessung hybrider Türme und Entwicklung eines geeigneten Monitoringkonzepts (HyTowering)

Bild zum Projekt Optimierung der Bemessung hybrider Türme und Entwicklung eines geeigneten Monitoringkonzepts (HyTowering)

Supervisor:

Prof. Dr.-Ing. Steffen Marx

Researcher:

Nikolai Penner, M.Sc., Benedikt Hofmeister, M.Eng.

Duration:

01.01.2018 - 31.12.2020

Funded by:

Federal Ministry for Economic Affairs and Energy

Brief description:

As tower heights continue to rise, hybrid towers made of pre-stressed concrete segments and mounted steel towers are increasingly being used for onshore wind turbines. The risk of instability or damage to the structure increases with height. The subject of the approved research project are large-scale tests on concrete segment towers. It is planned to develop design models and to test monitoring concepts.

 

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Gebrauchstauglichkeit und Komfort von dynamisch beanspruchten Holztragwerken im urbanen mehrgeschossigen Hochbau (DBH)

Bild zum Projekt Gebrauchstauglichkeit und Komfort von dynamisch beanspruchten Holztragwerken im urbanen mehrgeschossigen Hochbau (DBH)

Supervisor:

Henning Klattenhoff (ASSMANN BERATEN + PLANEN AG)

Researcher:

Dr.-Ing. Tanja Grießmann, Benedikt Hofmeister, M.Eng.

Duration:

2018- 2021

Funded by:

Deutsche Bundesstiftung Umwelt - Aktenzeichen 34548/01 - 25

Brief description:

Goal of the research project is the analysis of vibration phenomena of modern urban timber constructions and the development of innovative methods and standards for project planners and developers. In addition, digital measuring data and further results will be published. Due to the increasing demand for wooden buildings in an environment, which is highly dominated by traffic-induced vibrations, the dynamics of multistory buildings become design relevant and more and more urgent. In combination with the sustainability per se of wooden materials, a sufficient planning security establishes the precondition for future multistory buildings to be completely manufactured from wood, which will lead to a more sustainable construction method compared to reinforced concrete. As an outcome, relevant contributions to ensure vibration-dependent comfort characteristics of timber buildings are expected.

 

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Multivariate Structural Health Monitoring for Rotor Blades

Bild zum Projekt Multivariates Schadensmonitoring von Rotorblättern  (MultiMonitorRB)

Supervisor:

Prof. Dr-Ing. habil. Raimund Rolfes

Researcher:

- Dorian Pache, M.Sc., Christian Gerendt, M.Sc.

Duration:

01.03.2017 – 31.02.2020

Funded by:

Federal Ministry for Economic Affairs and Energy - FKZ 0324157A

Brief description:

Essential goals of the project “Multivariate Structural Health Monitoring for Rotor Blades” are to develop, combine and test global and local SHM methods for rotor blades of wind turbines. In sense of a multivariate procedure, different structure-mechanical and acoustic approaches, which are able to capture different indicators and damage parameters, will be considered. The SHM methods are to guarantee an automated and reliable detection and classification of relevant damages during the early stage.

 

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From the source to the perception

Bild zum Projekt Von der Schallquelle zur psycho-akustischen Bewertung (WEA-Akzeptanz)

Supervisor:

Prof. Dr-Ing. habil. Raimund Rolfes

Researcher:

Jasmin Hörmeyer, M.Sc., Susanne Martens, M.Sc., Tobias Bohne, M.Sc.

Duration:

01.04.2017 – 31.03.2020

Funded by:

Federal Ministry for Economic Affairs and Energy - FKZ 0324134A

Brief description:

In the project WEA-Akzeptanz an interdisciplinary approach will be followed, which links the physical sound generation, radiation and propagation with the perception at the immission site. In cooperation with the industrial partner Senvion, the IKT and the IMUK of the Leibniz Universität Hannover, an acoustic overall model will be developed comprising the sound generation at the wind turbine, the sound propagation to the receiver under realistic atmospheric conditions and a perception model.

 

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German Research Facility for Wind Energy (DFWind)

Bild zum Projekt Deutsche Forschungsplattform für Windenergie (DFWind)

Supervisor:

Prof. Dr.-Ing. habil. Raimund Rolfes (LUH), Dr.-Ing. Henrik Oertel (extern: DLR)

Researcher:

Dr.-Ing. Tanja Grießmann, Stefan Wernitz, M.Sc., Benedikt Hofmeister, M.Eng., Dorian Pache, M.Sc.

Duration:

01.01.2016 – 31.12.2018

Funded by:

Federal Ministry for Economic Affairs and Energy - FKZ 0325936E

Brief description:

The project aims to lay the foundation of a research and development platform which concentrates on the usage of wind turbines throughout the entire functional chain in a so far unattained quality. The research is focused on the interaction of the subsystems as part of the overall structure, under consideration of mutual influences of two separate wind turbines and the effect on the integrated network as well. The ISD will be concentrating on intelligent measurement data analysis, Structural Health Monitoring as well as the calculation of coupled dynamical systems.

 

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Joint research for raising the efficiency of wind energy converters within the energy supply system (ventus efficiens)

Bild zum Projekt Verbundforschung zur Steigerung der Effizienz von Windenergieanlagen im Energiesystem (ventus efficiens)

Supervisor:

Prof. Dr.-Ing. habil. Raimund Rolfes

Researcher:

Dr.-Ing. Cristian Gebhardt, Karsten Schröder, M.Sc.

Duration:

01.12.2014 - 31.12.2019

Funded by:

Ministry for Science and Culture of Lower Saxony

Brief description:

The research project focuses the efficiency of wind energy converters within the energy supply system. Although the production, installation and operation procedures of these are on a high level, a continuous raise of their efficiency is indispensable. Only with a constant raise in efficiency, costs of electricity can be reduced distinctly. For wind energy, this is of special interest due to the essential role that it will have in Europe’s future energy supply.

 

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Dynamical behavior and strength of structural elements with regeneration induced imperfections and residual stresses (SP B4 "Stochastic Structural Analysis" of CRC 871)

Bild zum Projekt Schwingungs- und Festigkeitsverhalten von Bauteilen mit regenerations-bedingten Imperfektionen und Eigenspannungen (TP B4 "Stochastische Strukturanalyse" des SFB 871)

Supervisor:

Prof. Dr.-Ing. habil. Raimund Rolfes

Researcher:

M.Sc. Ricarda Berger (since 2016), Dipl.-Ing. Timo Rogge (until 2015)

Duration:

2010-2021

Funded by:

German Research Foundation (DFG)

Brief description:

Real components comprise regeneration induced imperfections (geometry, material and residual stresses), that affect the structural behavior significantly. For the application example of the complex capital good of a compressor blisk, the regeneration influence is quantified in the starting dynamics and durability. The bases for the necessary probabilistic structural analysis are efficient computation approaches. Finally, an evaluation of the possible regeneration paths (competing and non-competing) is performed.

 

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