Research Projects

Fatigue

  • Evaluation and modelling of the fatigue damage behaviour of polymer composites at reversed cyclic loading
    The object of this joint research project (ISD - Leibniz Universität Hannover, ILK - TU Dresden, IKV - RWTH Aachen, IPC - TU Hamburg-Harburg) is the investigation of damage to continuous fibre-reinforced plastics caused by cyclic loading with load reversals. The main focus is on the physically based generalisation of existing damage evolution models as an essential part of the fatigue damage prediction of composite structures. Independent of the scale level considered, the type and amount of damage under cyclic loading is determined mainly by the imposed mean stress and amplitude and thus by the orientation of the varying load vector regarding to fibre direction. In the research project the damage phenomena and the degradation behaviour are analysed in detail by means of cyclic tests on microscopic model composites, single layers and laminates using optical stress analysis and in-situ computer tomography. With the help of further numerical analyses at micro level, physically based mathematical expressions are formulated for different stress ratios. The mathematical approaches developed are implemented in the FE-based fatigue damage model of the ISD, for which first validations for pulsating cyclic loads have already been carried out. Thus, it will be possible to overcome the current limitation of the known model approaches to mostly constant amplitude pulsating loading and to make an essential development step towards a realistic lifetime analysis of composites under variable amplitude loading.
    Leaders: Prof. Dr.-Ing. habil. Raimund Rolfes
    Team: Martin Brod, M.Sc.
    Year: 2015
    Sponsors: German Research Foundation(DFG) -Project number 281870175
    Lifespan: 01.04.2016-31.10.2019
  • Challenges of industrial application of nanomodified and hybrid material systems in lightweight rotor blade design (HANNAH)
    The HANNAH research project is the follow-up to the LENAH research project. In LENAH, material systems from the fields of nanomodified materials and hybrid laminates were developed, tested and numerically simulated. This allowed the high potential of these material systems for the application in rotor blade design to be demonstrated under laboratory conditions. The investigated material systems are far superior to currently established materials, especially with regard to fatigue resistance. In the follow-up project HANNAH the (further) development of production and simulation methods for these material systems for industrial standards is now in the foreground. On the one hand, the aim is to guarantee the excellent properties of the developed material systems in large-scale production and to be able to simulate the mechanical behaviour to answer industry-related issues. In this context, the ISD develops material-specific simulation models in order increase time and cost efficiency for processes of material development and component design for nanomodified materials and hybrid laminates.
    Leaders: Prof. Dr-Ing. habil. Raimund Rolfes
    Team: Christian Gerendt, M. Sc.; Betim Bahtiri, M. Sc.; Behrouz Arash, Dr. Ing.;
    Year: 2019
    Sponsors: Bundesministerium für Wirtschaft und Energie (BMWI) - FKZ 0324345A
    Lifespan: 01.03.2019 – 28.02.2022
  • Acting Principles of Nano-Scaled Matrix Additives for Composite Structures (FOR 2021)
    Beim Forschungsprojekt HANNAH handelt es sich um das Anschlussvorhaben des Forschungsprojekts LENAH. In LENAH wurden Werkstoffsysteme aus den Bereichen „nanomodifizierte Werkstoffe“ und „hybride Laminate“ entwickelt, getestet und numerisch simuliert. Hierdurch konnte das hohe Potential dieser Werkstoffsysteme für die Anwendung im Rotorblattbau zunächst unter Laborbedingungen nachgewiesen werden. Demnach sind die untersuchten Werkstoffsysteme insbesondere hinsichtlich der Ermüdungsresistenz aktuell etablierten Materialien weit überlegen. Im Folgeprojekt HANNAH steht nun die (Weiter-) Entwicklung von Fertigungs- und Simulationsverfahren für diese Werkstoffsysteme für industrielle Maßstäbe im Vordergrund. Ziel ist zum einen die hervorragenden Eigenschaften der entwickelten Werkstoffsysteme auch in der Großserienproduktion zu gewährleisten sowie das mechanische Verhalten zur Beantwortung industrienaher Fragestellungen simulieren zu können. In diesem Kontext entwickelt das ISD materialspezifische Simulationsmodelle, um in Zukunft Prozesse der Materialentwicklung sowie der Bauteilauslegung für nanomodifizierte Werkstoffe und hybride Laminate kosten- und zeiteffizient auf Basis numerischer Prognosen gestalten zu können.
    Leaders: Prof. Dr-Ing. habil. Raimund Rolfes
    Team: Christian Gerendt, M.Sc. ; Betim Bahtiri, M.Sc. (ab 1. Mai 2020)
    Year: 2019
    Sponsors: Bundesministerium für Wirtschaft und Energie (BMWI) - FKZ 0324345A
    Lifespan: 01.03.2019 – 28.02.2022
  • New methods for failure and fatigue analysis of suction panels for laminar flow control
    Although the suction panel concept holds a high potential to increase the sustainability of future aircrafts, it comes with some structural mechanical challenges that need to be carefully examined. With the panel’s underlying backbone structure adopting the load-carrying function of the outer airfoil in the suction area (see Fig. 1), the stress flux in the airfoil is considerably disturbed, resulting in multiple, potentially critical stress concentrations. To ensure a sufficient robustness of the suction panel concept in terms of static strength and fatigue resistance, the backbone structure is to be analyzed numerically by means of finite element simulations. With deep knowledge in the field of continuum damage mechanics and progressive fatigue analysis, ISD will perform high fidelity strength and fatigue analyses of the backbone structure to identify sufficiently robust designs of the backbone structure. To calibrate the numerical methods, experimental coupon tests of the backbone structure’s base material are scheduled to identify respective static and fatigue-related material properties. Beside the identification of mechanically robust designs of the suction panel, the numerical simulations are also to address topics like scalability of the suction concept and the benefits of thin ply laminates, which are well known to feature a superior fatigue resistance.
    Leaders: Prof. Dr-Ing habil Raimund Rolfes
    Team: Muzzamil Tariq, Christian Gerendt, Dr-Ing. Sven Scheffler
    Year: 2019
    Sponsors: DFG, German Research Foundation
    Lifespan: 01.04.2019-31.12.2022
  • Modeling and simulation of the fatigue damage behavior of fiber composites under variable block loading conditions
    The goal of this research project is the extension and application of a progressive fatigue damage model for unidirectional multi-layered fiber composites for damage analysis under variable cyclic block loading patterns. The focus is on the development of damage evolution laws to accurately predict the degradation of strength and stiffness properties based on the load direction and the stress level. In addition to the influence of load sequence effects, particular attention will be paid to the effects of passive damage occurring under combined cyclic tension and compression loading. Finally, the extended fatigue damage model is to be applied to a fuselage structure segment of a future passenger aircraft for fatigue analysis.
    Leaders: Prof. Dr.-Ing. habil. Raimund Rolfes
    Team: M.Sc. Marting Brod
    Year: 2020
    Sponsors: Internes Projekt
    Lifespan: seit 2020
  • Global-local thermomechanical analysis of fracture in polycrystalline silicon shells using a phase-field approach.
    Abstract: The existing works in the literature addressing damage events in PV-Modules have different drawbacks and needs for improvements. On the one hand, the lack of a computationally efficient multiscale-based framework to model progressive failure in PSWs is observed. Furthermore, a coupled thermomechanical phase-field modeling framework for shells based on the geometrically nonlinear theory which takes into account the anisotropy effects as well as the presence of residual stresses is not yet available. Thus, the present proposal aims at covering these shortcomings in a unified way and at modeling progressive failure at both the micro- and macroscale by developing a theoretically robust and computationally efficient framework. This project is carried out in a close collaboration with the Institute of Applied Mechanics of the Technische Universität Braunschweig.
    Leaders: Prof. Dr-Ing. habil. Raimund Rolfes
    Team: Muzzamil Tariq, M.Sc.
    Year: 2020
    Sponsors: DFG, German Research Foundation
    Lifespan: Muzzamil Tariq, M.Sc.

Structures

  • Development of a safety cockpit for gliders (CraCpit)
    The aim is to develop a crash retrofit solution made of composite materials for gliders. Particularly challenging is the rapid loading, which requires a non-linear viscoelastic damage model. The high complexity of the model, resulting from the high level of geometric detail. The energy dissipation and the separation of subcomponents is a particular challenge during the explicit calculation. The developed and simulated retrofit solution is validated in a large-scale test on a glider.
    Leaders: Prof. Dr-Ing habil. Raimund Rolfes
    Team: Oliver Dorn, M.Sc., Dr.-Ing. Sven Scheffler
    Year: 2017
    Sponsors: Federal Ministry for Economic Affairs and Energy – 20E1703D
    Lifespan: 2018-2021
  • Improved structural performance through the use of random field analysis
    The research performed within this project uses the effect of random variations in structure’s geometry and/or material to get information on local sensitivity of structures to deviations from their baseline value. This information cannot only be useful in quality assurance, by finding areas most sensitive to deviations, but can also be used to improve the design. This approach can load to an increase in structural parameters such as buckling load, fatigue life and others.
    Leaders: Prof. Dr-Ing habil. Raimund Rolfes
    Team: Muzzamil Tariq, M.Sc.
    Year: 2019
    Sponsors: SE²A excellence, Cluster of DFG
    Lifespan: 2019-2022
  • Multistable Morphing Structures using Variable Stiffness Composites
    The research project aims at developing multistable structures with morphing capabilities. A variable stiffness composite is used which allows stiffness tailoring with much larger design space. The developed semi analytical method is validated well within a Finite element framework. In this work, the concept of static, smart and dynamic actuations are exploited on bistable laminates to reduce the snap-through requirements.
    Leaders: Prof. Dr-Ing habil. Raimund Rolfes
    Team: Anilkumar P M Nair, M.Tech.
    Year: 2019
    Sponsors: Deutscher Akademischer Austauschdienst (DAAD)
    Lifespan: 2019-2021
  • FANFOLD – Fast nonlinear machine learned analysis for rotor blades
    Constructions made of fiber-plastic composites are primarily light and thin-walled. Different semi-finished products (materials, weaving etc.) give the designer a wide range of possibilities. Thus, a component can be dimensioned and manufactured according to the requirements and stresses. But exactly this dimensioning requires a complex determination of the material parameters of the unidirectional single layer. If the strengths and stiffnesses are too low, the structure becomes too heavy, if they are too high, the structure may fail. In a novel approach, the structural properties of the laminate will be predicted by machine learning. By means of an orthotropic damage model a fast nonlinear calculation shall be realized. The goal is to shorten the calculation and development time.
    Leaders: Prof. Dr-Ing. habil. Raimund Rolfes
    Team: Oliver Dorn, M.Sc., Dr.-Ing. Sven Scheffler
    Year: 2020
    Sponsors: Federal Ministry for Economic Affairs and Energy – FKZ 03EE3028A
    Lifespan: 2020 –2023

Nanocomposites

  • Acting Principles of Nano-Scaled Matrix Additives for Composite Structures (FOR 2021)
    The research project aims at gaining a comprehensive understanding of the acting mechanism of nano-scaled additives to polymer matrices of continuous fibre reinforced polymer composites with respect to improved matrix dominated properties. Particularly, a sequential multi-scale simulation scheme for the prediction of mechanical properties is developed, ranging from particle-matrix interactions on nano scale up to fibre reinforced materials on micro/meso scale. It combines Finite Element and atomistic simulations based on the Molecular Dynamic Finite Element Method (MDFEM).
    Leaders: Prof. Dr-Ing. habil. Raimund Rolfes
    Team: Atiyeh Mousavi, M.Sc., Johannes Fankhänel, Dipl.-Ing.
    Year: 2017
    Sponsors: Deutsche Forschungsgemeinschaft (DFG)
    Lifespan: 01.07.2017 – 31.10.2020
  • Challenges of industrial application of nanomodified and hybrid material systems in lightweight rotor blade design (HANNAH)
    The HANNAH research project is the follow-up to the LENAH research project. In LENAH, material systems from the fields of nanomodified materials and hybrid laminates were developed, tested and numerically simulated. This allowed the high potential of these material systems for the application in rotor blade design to be demonstrated under laboratory conditions. The investigated material systems are far superior to currently established materials, especially with regard to fatigue resistance. In the follow-up project HANNAH the (further) development of production and simulation methods for these material systems for industrial standards is now in the foreground. On the one hand, the aim is to guarantee the excellent properties of the developed material systems in large-scale production and to be able to simulate the mechanical behaviour to answer industry-related issues. In this context, the ISD develops material-specific simulation models in order increase time and cost efficiency for processes of material development and component design for nanomodified materials and hybrid laminates.
    Leaders: Prof. Dr-Ing. habil. Raimund Rolfes
    Team: Christian Gerendt, M. Sc.; Betim Bahtiri, M. Sc.; Behrouz Arash, Dr. Ing.;
    Year: 2019
    Sponsors: Bundesministerium für Wirtschaft und Energie (BMWI) - FKZ 0324345A
    Lifespan: 01.03.2019 – 28.02.2022
  • Acting Principles of Nano-Scaled Matrix Additives for Composite Structures (FOR 2021)
    Beim Forschungsprojekt HANNAH handelt es sich um das Anschlussvorhaben des Forschungsprojekts LENAH. In LENAH wurden Werkstoffsysteme aus den Bereichen „nanomodifizierte Werkstoffe“ und „hybride Laminate“ entwickelt, getestet und numerisch simuliert. Hierdurch konnte das hohe Potential dieser Werkstoffsysteme für die Anwendung im Rotorblattbau zunächst unter Laborbedingungen nachgewiesen werden. Demnach sind die untersuchten Werkstoffsysteme insbesondere hinsichtlich der Ermüdungsresistenz aktuell etablierten Materialien weit überlegen. Im Folgeprojekt HANNAH steht nun die (Weiter-) Entwicklung von Fertigungs- und Simulationsverfahren für diese Werkstoffsysteme für industrielle Maßstäbe im Vordergrund. Ziel ist zum einen die hervorragenden Eigenschaften der entwickelten Werkstoffsysteme auch in der Großserienproduktion zu gewährleisten sowie das mechanische Verhalten zur Beantwortung industrienaher Fragestellungen simulieren zu können. In diesem Kontext entwickelt das ISD materialspezifische Simulationsmodelle, um in Zukunft Prozesse der Materialentwicklung sowie der Bauteilauslegung für nanomodifizierte Werkstoffe und hybride Laminate kosten- und zeiteffizient auf Basis numerischer Prognosen gestalten zu können.
    Leaders: Prof. Dr-Ing. habil. Raimund Rolfes
    Team: Christian Gerendt, M.Sc. ; Betim Bahtiri, M.Sc. (ab 1. Mai 2020)
    Year: 2019
    Sponsors: Bundesministerium für Wirtschaft und Energie (BMWI) - FKZ 0324345A
    Lifespan: 01.03.2019 – 28.02.2022

Material Modeling

  • Virtual Materials and their Validation: German-French School of Computational Engineering (ViVaCE)
    Compressive failure mechanism of unidirectional fibre composites has been studied extensively over the past decades. Stochastic fibre misalignments were identified as an essential factor in the prediction of compressive strength. There is a need to characterize the effects of distribution of misalignment on the strength values in compressive regime. Hence, the scope of this project is to further the development in this regard and extend the definition of failure surfaces under compressively dominated loads by statistical information. A probabilistic definition of failure surface based on imperfections at micro level, and a subsequent experimental validation are the goals of the project. This would lead to subsequent better representation of material properties at the macro scale.
    Leaders: Prof. Dr-Ing. habil. Raimund Rolfes
    Team: Nabeel Safdar, M.Sc., Benedikt Daum, Dipl.-Ing. Dr.
    Year: 2016
    Sponsors: Deutsche Forschungsgemeinschaft – DFG (International Research and Training Group IRTG1627)
    Lifespan: 01.12.2016 – 30.09.2019
  • Development and validation of a virtual process chain for composite structural components considering imperfections with application to a rotor blade component (Prosim R)
    Within the scope of this research project, the essential parts of the process chain in the production of a rotor blade are to be numerically simulated and fundamentally investigated. The primary goal is the reduction of defects in the production of fiber composite materials with the help of simulating the full process chain (manufacturing simulation and structural analysis). In order to obtain a statement on material behaviour and progressive failure, the ISD will extend the sequential multi-scale analysis by including imperfections at the ISD. The results of the draping and infusion simulation are thereby the input information.
    Leaders: Prof. Dr-Ing. habil. Raimund Rolfes
    Team: Gerrit Gottlieb, M.Sc., Benedikt Daum, Dipl.-Ing. Dr.
    Year: 2017
    Sponsors: German Research Foundation (DFG) - Project number 329147126
    Lifespan: 01.08.2017 – 31.07.2020
  • Modeling and simulation of the fatigue damage behavior of fiber composites under variable block loading conditions
    The goal of this research project is the extension and application of a progressive fatigue damage model for unidirectional multi-layered fiber composites for damage analysis under variable cyclic block loading patterns. The focus is on the development of damage evolution laws to accurately predict the degradation of strength and stiffness properties based on the load direction and the stress level. In addition to the influence of load sequence effects, particular attention will be paid to the effects of passive damage occurring under combined cyclic tension and compression loading. Finally, the extended fatigue damage model is to be applied to a fuselage structure segment of a future passenger aircraft for fatigue analysis.
    Leaders: Prof. Dr.-Ing. habil. Raimund Rolfes
    Team: M.Sc. Marting Brod
    Year: 2020
    Sponsors: Internes Projekt
    Lifespan: seit 2020

Structural Health Monitoring

  • Monitoring the Suction Bucket Jacket at the Offshore Wind Farm Borkum Riffgrund 1 (Monitoring SBJ)
    The research project “Monitoring SBJ” is a joint project between DONG Energy, Leibniz Universität Hannover (LUH), and the Federal Institute for Materials Research and Testing (BAM). It is based on measured data gathered from the comprehensive monitoring system mounted on the recently installed Suction Bucket Jacket prototype foundation, located at the offshore wind farm Borkum Riffgrund 1. The tasks of ISD are the processing of measurement data from ambient vibration during installation and operation and the improvement of a numerical model in terms of the soil-structure-interaction.
    Leaders: Prof. Dr.-Ing. habil. Raimund Rolfes
    Team: Nikolai Penner, M.Sc., Dipl.-Ing. Andreas Ehrmann
    Year: 2014
    Sponsors: Federal Ministry for Economic Affairs and Energy
    Lifespan: 01.08.2014 - 28.02.2017
  • German Research Facility for Wind Energy (DFWind)
    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.
    Leaders: Prof. Dr.-Ing. habil. Raimund Rolfes
    Team: Dr.-Ing. Tanja Grießmann, Stefan Wernitz, M.Sc., Benedikt Hofmeister, M.Eng.
    Year: 2016
    Sponsors: Federal Ministry for Economic Affairs and Energy - FKZ 0325936E
    Lifespan: 01.01.2016 – 31.12.2020
    © DLR
  • Multivariate Structural Health Monitoring for Rotor Blades
    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.
    Leaders: Prof. Dr-Ing. habil. Raimund Rolfes
    Team: Marlene Bruns, M.Sc., Helge Jauken, M.Sc.
    Year: 2017
    Sponsors: Federal Ministry for Economic Affairs and Energy - FKZ 0324157A
    Lifespan: 01.03.2017 – 31.12.2020
    © ISD
  • Optimierung der Bemessung hybrider Türme und Entwicklung eines geeigneten Monitoringkonzepts (HyTowering)
    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.
    Leaders: Prof. Dr.-Ing. habil. Raimund Rolfes
    Team: Nikolai Penner, M.Sc., Benedikt Hofmeister, M.Eng.
    Year: 2018
    Sponsors: Federal Ministry for Economic Affairs and Energy
    Lifespan: 01.01.2018 - 31.12.2020
    © ISD
  • Qualitätsgesicherte Fließfertigung leichter UHFB-Stabelemente mittels Künstlicher Neuronaler Netze (SPP 2187)
    Gemeinsam mit dem Institut für Baustoffe forscht das ISD an einem neuartigen Herstellungsverfahren für Bauteile aus ultra-hochfestem Beton mit einer Bewehrung aus Stahlblech und Kohlenstofffasern. In einem innovativen Strangpressverfahren werden stabförmige Bauteile hergestellt, die einen Kern aus ultra-hochfestem Beton haben. Sie sind durch eine Kombination aus kohlenstofffaserverstärktem Kunststoff und Stahlblech bewehrt. Es wird ein Sensorkonzept entwickelt, welches in der Lage die, die Bauteile „ab Bauteilgeburt“ zu überwachen. Verschiedene heterogene Messdaten werden genutzt, um den Prozess des Strangpressens mithilfe eines Künstlichen Neuronalen Netzes zu steuern und zu überwachen, sodass eine gleichbleibend hohe Qualität der Bauteile gewährleistet werden kann.
    Leaders: Prof. Dr.-Ing. habil. Raimund Rolfes
    Team: Nikolai Penner, M.Sc., Dipl.-Ing. Franz Ferdinand Tritschel
    Year: 2019
    Sponsors: Deutsche Forschungsgemeinschaft (DFG) - Projektnummer 402702316
    Lifespan: 2019 - 2022

Acoustics

  • Research on and testing of noise mitigation measures during the construction of the FINO3-monopile (Schall FiNO3)
    The research project aims at the prototypic application of a big bubble curtain during the pile driving activities to install the FINO3-research platform in the German North Sea. It is planned to evaluate the efficiency of the mitigation concept to protect the marine environment against sound immissions during a short test program subsequent to the main piling procedure. In parallel, measures within the ecological accompanying research will be taken.
    Leaders: Prof. Dr.-Ing. habil. Raimund Rolfes
    Team: Jörg Rustemeier, M.Sc., Dr.-Ing. Tanja Grießmann
    Year: 2008
    Sponsors: Federal Ministry for the Environment, Nature Conservation, Building and Nuclear Safety - FKZ 0325023A
    Lifespan: 01.01.2008 - 31.03.2009
  • Investigation of Sonar Transponders for Offshore Wind Farms and Technical Integration to an Overall Concept
    Offshore Wind Energy Converters require the installation and operation of sonar transponder units in order to achieve an acoustical warning of submarines. In order to assure a sufficient signal-to-noise ratio and a certain operation distance even under bad conditions the source level of the sonar transponder has to be high enough. On the other hand the bad influence on marine mammals has to be minimized. Beside the dimensioning of the transponders according to the requirements of the German navy an additional goal is the modeling of the sound propagation by means of a hybrid approach.
    Leaders: Prof. Dr.-Ing. habil. Raimund Rolfes
    Team: Dipl.-Ing. Moritz Fricke
    Year: 2009
    Sponsors: Federal Ministry for the Environment, Nature Conservation, Building and Nuclear Safety - FKZ 0325104A
    Lifespan: 01.02.2009 - 31.03.2011
  • Realistic underwater noise scenarios on the basis of forecasting models and monitoring for the construction of offshore wind farms in the German North Sea (HyproWind)
    The research project aims at the development of a multi-stage numerical method for the prediction of underwater sound immissions related to pile driving in the German North Sea. The focus is not on the modeling of the source, but on an efficient calculation of the sound propagation for longer distances with a subsequent visualization in noise maps. Moreover, hydro-acoustic long-term measurements for model validation near the research platforms FINO1 and FINO3 are planned.
    Leaders: Prof. Dr.-Ing. habil. Raimund Rolfes
    Team: Dipl.-Ing. Moritz Fricke, Dr.-Ing. Tanja Grießmann
    Year: 2010
    Sponsors: Federal Ministry for the Environment, Nature Conservation, Building and Nuclear Safety - FKZ 0325212
    Lifespan: 01.09.2010 - 31.12.2013
  • Predicting Underwater Noise due to Offshore Pile Driving: Modeling of Noise Reduction Methods (BORA)
    The global target of the joint project BORA is to develop a calculation model to predict waterborne noise due to offshore pile driving. This includes especially models to predict the sound development at the source due to pile deformation and vibration, the sound transmission into water and soil and the consideration of the sound attenuation due to the air-water mixture produced by bubble curtains or due to other sound reduction methods.
    Leaders: Prof. Dr.-Ing. habil. Raimund Rolfes
    Team: Tobias Bohne, M.Sc.
    Year: 2012
    Sponsors: Federal Ministry for Economic Affairs and Energy - FKZ 0325421B
    Lifespan: 01.12.2009 - 30.11.2014
  • From the source to the perception
    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.
    Leaders: Prof. Dr-Ing. habil. Raimund Rolfes
    Team: Jasmin Hörmeyer, M.Sc., Susanne Martens, M.Sc., Tobias Bohne, M.Sc.
    Year: 2017
    Sponsors: Federal Ministry for Economic Affairs and Energy - FKZ 0324134A
    Lifespan: 01.04.2017 – 30.11.2020
    © ISD

Coupled Dynamic Systems

  • Life time - Research on Support Structures in the Offshore Test Site alpha ventus (GIGAWIND life)
    Goal of the comprehensive project is the enhancement of the economic dimensioning concept for offshore wind turbine support structures, that has been developed in GIGAWIND alpha ventus, by consideration of long-time operation. There are both degradation mechanisms on the resistance side of the environmental surrounded support structure (damages of structure and welds, fatigue, damages of corrosion protection systems, scour, degradation of pile support behavior) and the determination of acting loads from waves and marine growth.
    Leaders: Prof. Dr.-Ing. habil. Raimund Rolfes
    Team: Dipl.-Ing. Jan Häfele, Nikolai Penner, M.Sc., Dr.-Ing. Tanja Grießmann, Dipl.-Ing. Andreas Ehrmann, Dr.-Ing. Mahmoud M. Jahjouh
    Year: 1000
    Sponsors: Federal Ministry for Economic Affairs and Energy - FKZ 0325575A
    Lifespan: 01.02.2013 - 31.01.2018
  • Innovative Wind Conversion Systems (10-20 MW) for Offshore Applications (INNWIND.EU)
    The research project with a total of 27 European partners is an ambitious successor for the UpWind project, where the vision of a 20MW wind turbine was put forth with specific technology advances that are required to make it happen. The overall objectives of the INNWIND.EU project are the high performance innovative design of a beyond-state-of-the-art 10-20MW offshore wind turbine and hardware demonstrators of some of the critical components.
    Leaders: Prof. Dr. Ing.-habil. Raimund Rolfes
    Team: Dipl.-Ing. Jan Häfele
    Year: 2012
    Sponsors: European Union
    Lifespan: 01.11.2012 - 31.10.2017
  • Suction bucket foundations as an innovative and installation noise-reducing concept for offshore wind turbines (WindBucket)
    The overall goal of the research project „WindBucket“ is to assess the feasibility and possible applications and limitations as well as creating necessary conditions for planning, design and construction of bucket foundations of steel and reinforced concrete in German offshore fields. The tasks of ISD include the preparation of an integrated multi-physical model of the offshore wind turbine to study the dynamic behavior applying modal analysis and transient simulation under the consideration of soil-structure-interaction.
    Leaders: Prof. Dr.-Ing. habil. Raimund Rolfes
    Team: Dipl.-Ing. Andreas Ehrmann, Małgorzata Szałyga, M.Sc.
    Year: 2012
    Sponsors: Federal Ministry for Economic Affairs and Energy - FKZ 0325406B
    Lifespan: 01.07.2012 - 30.09.2014
  • Integrated Research Programme on Wind Energy (IRPWIND)
    The aim of the IRPWIND is to foster better integration of European wind energy research activities with the aim of accelerating the transition towards a low-carbon economy and maintain and increase European competitiveness. IRPWIND focusses on three main research aspects. The first one is the optimization of wind farms through the validation of integrated design models. The second one is the reduction of the uncertainty in order to increase efficiency and reliability of future wind turbines. The last one is the transformation of the energy supply system.
    Leaders: Prof. Dr.-Ing. habil. Raimund Rolfes
    Team: Clemens Hübler, M.Sc., Karsten Schröder, M.Sc.
    Year: 2014
    Sponsors: European Union
    Lifespan: 01.03.2014 - 30.04.2018
  • Dynamical behavior and strength of structural elements with regeneration induced imperfections and residual stresses (SP B4 "Stochastic Structural Analysis" of CRC 871)
    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.
    Leaders: Prof. Dr.-Ing. habil. Raimund Rolfes
    Team: M.Sc. Ricarda Berger (since 2016), Dipl.-Ing. Timo Rogge (until 2015)
    Year: 2014
    Sponsors: German Research Foundation (DFG)
    Lifespan: 2010-2021
    © ISD
  • Probabilistic Safety Assessment of Offshore Wind Turbines (PSA)
    In diesem themenübergreifenden Verbundprojekt soll die für den Bemessungsprozess zentrale Frage der Versagenswahrscheinlichkeit in den aktuellen Bemessungen von OWEA geklärt werden. Hierfür werden mit Hilfe von probabilistischen Methoden Versagenswahrscheinlichkeiten für die Grenzzustände berechnet. Die vorhandenen Versagensarten der Tragstruktur werden in einer Fehlerbaumanalyse zusammengeführt und die wahrscheinlichste Versagensart sowie die resultierende Versagenswahrscheinlichkeit können bestimmt werden.
    Leaders: Prof. Dr-Ing. habil. Raimund Rolfes
    Team: Jan Goretzka, M.Sc.
    Year: 2014
    Sponsors: Ministry for Science and Culture in Lower Saxony
    Lifespan: 01.12.2009-30.11.2014
  • Joint research for raising the efficiency of wind energy converters within the energy supply system (ventus efficiens)
    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.
    Leaders: Prof. Dr.-Ing. habil. Raimund Rolfes
    Team: Dr.-Ing. Cristian Gebhardt, Karsten Schröder, M.Sc.
    Year: 2015
    Sponsors: Ministry for Science and Culture of Lower Saxony
    Lifespan: 01.12.2014 - 31.12.2019
    © ForWind
  • Precise measuring system for contactless recording and analysis of the dynamic flow behaviour of wind turbine rotor blades (PreciWind)
    Within the framework of the PreciWind project, a mobile thermographic measuring system for the continuous recording and analysis of the dynamic flow behaviour of rotor blades on wind turbines in operation is being developed. With the system developed for use on operational turbines in wind parks, the aerodynamic performance of wind turbines in operation can be quantified and evaluated. The analysis of the boundary layer flow conditions is carried out with a geometrically high-resolution infrared camera in the long-wave radiation range. In combination with a laser distance measuring system to record the rotor blade distance and geometry, the measuring system is fixed on a co-rotating measuring system carrier in order to examine the flow behaviour during a complete revolution of the rotor for the first time. This arrangement enables the compensation of the relative movements between the measuring system and the wind turbine rotor and at the same time enables an analysis of the structural dynamics of the wind turbine due to changing force effects within a rotor revolution. Using a mobile power supply, measurements can be carried out in real wind park conditions from distances of up to 300 m to the wind turbine. The main task of the ISD is to numerically investigate the full measuring activities by applying the concept of a digital twin. A virtual image of the wind energy turbine and the entire measurement system will be designed in detail. To determine effective positions and adjustments of the measurement system, various simulations under different environment conditions will be performed. A validation of the simulations is carried out using high-quality measurement data.
    Leaders: Prof. Dr-Ing. habil. Raimund Rolfes, PD Dr.-Ing. habil. Cristian Guillermo Gebhardt
    Team: Daniel Schuster, M. Sc., Dipl.-Ing. (FH) Christian Hente, M.Sc.
    Year: 2020
    Sponsors: Bundesministerium für Wirtschaft und Energie - FKZ 03EE3013B
    Lifespan: 01.01.2020 – 31.12.2022
    © BIMAQ

Uncertainty

  • Efficient modelling of wind turbines in time-domain considering uncertain parameters (ENERGIZE)
    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.
    Leaders: Prof. Dr.-Ing. habil. Raimund Rolfes, Dr.-Ing. Cristian Gebhardt
    Team: Dr.-Ing. Clemens Hübler
    Year: 2019
    Sponsors: Deutsche Forschungsgemeinschaft (DFG)
    Lifespan: 2019 – 2022
    © ISD
  • Transdisciplinary end-of-life analysis of wind turbines for the development of technically and economically optimal end-of-funding strategies (TransWind)
    Wind energy is an important pillar for achieving the energy transition in Germany. Electricity generation costs are still high in relation to market compensation, so that there is a need for development. Hence, the end-of-life topic of wind turbines - i.e. the analysis and design of the period after the end of the funding by the “Erneuerbare Energien Gesetzes” (EEG) or after the design lifetime has been exceeded – is currently of particular interest. To develop technically and economically sustainable strategies for post-EEG wind turbines, a joint and at least partly coupled consideration of different aspects of structural dynamics, logistics, spatial planning, and economics is indispensable. For example, it only makes sense to analyse the economic feasibility of continued operation by retrofitting if this is also technically possible. Therefore, within TransWind project, a probabilistic, structural-dynamic model of a wind turbine will be combined with site-specific wind simulations, spatial planning tools and economic analyses in an integrated modelling approach. To enable the automated application of this transdisciplinary approach, the modelling approach will be implemented in a software solution, and thus, takes advantage of the increasing digitalisation of the energy industry. The focus of the ISD is on the structural-dynamic, probabilistic lifetime calculations.
    Leaders: Dr.-Ing. Clemens Hübler, Prof. Dr-Ing. habil. Raimund Rolfes
    Team: Franziska Müller, M.Sc.
    Year: 2020
    Sponsors: Federal Ministry for Economic Affairs and Energy - FKZ 03EE3029A
    Lifespan: 01.11.2020 – 31.10.2023
    © WIV GmbH
  • VIPile – Influence of vibration parameters on the installation and load-bearing behaviour of monopiles
    The results of the first two rounds of auctions for German offshore wind farms with commissioning from 2021 to 2025 illustrate the necessity of exploiting further cost reduction potentials in order to realise these future projects within the targeted cost ranges. One possibility is the use of vibratory pile driving as an environmentally friendly and cost-effective construction method for the realisation of further expansion plans for offshore wind energy in Germany. The VIPile project pursues the overall goal of developing validated simulation models for predicting the load-bearing behaviour of vibrated monopile foundations by means of large-scale experiments and numerical simulations. This aims at enabling an economic evaluation and reducing the corresponding risks during project realisations. In addition, a simplified, less computationally intensive, linearized soil-structure interaction model will be developed, which can be integrated into fully coupled aero-elastic wind turbine simulations. This simplified model will be derived from the previously developed detailed models and validated with the help of dynamic measurements. The focus of the ISD is on the simplified soil-structure interaction model.
    Leaders: Prof. Dr.-Ing. habil. Raimund Rolfes, Dr.-Ing. Clemens Hübler
    Team: Marlene Bruns, M.Sc.
    Year: 2020
    Sponsors: Bundesministerium für Wirtschaft und Energie - FKZ 03EE3022
    Lifespan: 01.08.2020 – 31.07.2023
    © ISD