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

Development and validation of a virtual process chain for composite structural components considering imperfections with application to a rotor blade component (Prosim R)

 

Supervisor:

Prof. Dr-Ing habil. Raimund Rolfes

Researcher:

Gerrit Gottlieb, M.Sc.

Duration:

2017 - 2020

Funded by:

Deutsche Forschungsgemeinschaft (DFG)

Brief description:

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.

 

 

A Stochastic Multiscale Approach for Compressive Failure Analysis of Composites.

Bild zum Projekt Ein stochastischer Multiskalen-Ansatz für die druckabhängige Schadensanalyse (Compressive-Failure-Analyse) von Verbundwerkstoffen.

Supervisor:

Prof. Dr-Ing habil. Raimund Rolfes

Researcher:

Nabeel Safdar, M.Sc.

Duration:

2016 - 2019

Funded by:

Deutsche Forschungsgemeinschaft (DFG), IRTG1627

Brief description:

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.

 

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Lifetime increase and lightweight design of rotor blades through nano particle modified and hybrid composites (LENAH) - Nano particle modifications

Bild zum Projekt Lebensdauererhöhung und Leichtbauoptimierung durch nanomodifizierte und hybride Werkstoffsysteme im Rotorblatt (LENAH) - Nanopartikel-Modifikation

Supervisor:

Prof. Dr-Ing. habil. Raimund Rolfes

Researcher:

M.Sc. Robin Unger

Duration:

2015-2018

Funded by:

Federal Ministry of Education and Research (BMBF)

Brief description:

The research focus on the detailed modeling of composite materials with nano-scaled matrix additives. The specific objective is to gain comprehensive knowledge on the complex interaction between nano particles and the matrix, as well as the enhancement of advanced material models, in order to improve the numerical development possibilities. In order to accomplish this, numerical investigations from the nano to the macro scale are done by using the MDFEM method, which enables the user to combine atomistic simulations with continuum mechanics.

 

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Acting Principles of Nano-Scaled Matrix Additives for Composite Structures (FOR 2021)

Bild zum Projekt Wirkprinzipien nanoskaliger Matrixadditive für den Faserverbundleichtbau (FOR2021)

Supervisor:

Prof. Dr.-Ing. habil. Raimund Rolfes

Researcher:

Dipl.-Ing. Johannes Fankhänel

Duration:

2014-2017

Funded by:

Deutsche Forschungsgemeinschaft (DFG)

Brief description:

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).

 

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Finite element analyses and simulation of the failure of short-fiber reinforced thermoplastics and aluminum blanks by clinching

Bild zum Projekt Numerische und experimentelle Untersuchungen zum Versagen beim Clinchen von kurzfaserverstärkten Thermoplasten mit Aluminium-Blechwerkstoffen

Supervisor:

Prof. Dr-Ing. habil. Raimund Rolfes

Researcher:

M.Sc. Aamir Dean

Duration:

2014-2016

Funded by:

German Research Foundation (DFG)

Brief description:

In the scope of this sub-project inside the SPP1640, the clinching process of short fiber reinforced thermoplastics with aluminum sheets is investigated numerically and experimentally. Based on the finite element method (FEM), the thermo-mechanical behavior of the thermoplastic and the aluminum is modeled and integrated into an overall parameterized simulation model. Comparing the simulations with the experimental investigations with respect to the forming process and the strength of the joint, a guideline for manufacturing hybrid joints is to be prepared finally.

 

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Multistable Morphing Structures using Variable Stiffness Composites

Bild zum Projekt Auslegung von Multistabile Strukturen mithilfe von Faserverbunden veränderlicher Steifigkeit

Supervisor:

Prof. Dr-Ing. habil. Raimund Rolfes

Researcher:

M.Sc. Ayan Haldar

Duration:

2013-2016

Funded by:

DFG, IRTG 1627

Brief description:

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 with the Finite element method for determining the multistable shapes of the variable stiffness composites. A parametric study is carried out to find the relation between fiber orientations and snap through forces. The aim will be to generate multistable structures with maximum out of plane displacement and minimum snap through forces.

 

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Experimental and Numerical-analytical investigation of the damage behavior of the high-performance Composites in the very high cycle regime (SPP 1466)

Bild zum Projekt Experimentelle und numerisch analytische Erforschung des Schädigungsverhaltens von Hochleistungsfaserverbunden unter sehr hohen Belastungszyklen (SPP 1466)

Supervisor:

Prof. Dr-Ing. habil. Raimund Rolfes

Researcher:

M.Sc. Hinesh Madhusoodanan

Duration:

2013-2016

Funded by:

German Research Foundation (DFG)

Brief description:

n technical applications of the wind energy and the aerospace industries high-performance composites are used, since the intended service times are of 30 years, which generally corresponds to about 10e10 load cycles. The present knowledge about the fatigue behavior of those composite materials is generally only valid for a maximal number of about 10e6 load cycles. The researches within this project focus on the damage mechanisms of anisotropic composites in the “very high cycle fatigue” (VHCF, up to 10e10 load cycles) range. Concerning this, both experimental and numerical investigations are carried out.

 

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Dynamic and aeroelastic analysis of the smart rotor blades equipped with morphing trailing edge

Bild zum Projekt Dynamische und aeroelastische Analyse der intelligenten Rotorblätter mit Morphing-Hinterkante

Supervisor:

Prof. Dr.-Ing. habil. Raimund Rolfes

Researcher:

M.Sc. Mehdi Garmabi

Duration:

2013-2015

Funded by:

Federal Ministry of Economic Affairs and Energy (BMWi, FKZ 41V6730))

Brief description:

A trend in the wind turbine industry is to raise the power performance and to reduce the energy cost by increasing the size of the wind turbines. As a secondary effect, the fatigue loads on rotor blades are increased, too. The aim of the Smart Blades project is to reduce those fatigue loads, by utilizing the concepts of passive and active smart blades. The ISD is involved in many areas of researches on the concept of active smart blades equipped with flexible trailing edge. The focus in this part of project is devoted to high-fidelity aeroelastic analyses. Through this kind of aeroelastic analysis, efficiency of the concept of the active smart blades can be determined in more details.

 

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Mikrorisse - Ursachen und Folgen für die Langzeitstabilität von PV-Modulen (Mikro)

Bild zum Projekt Mikrorisse - Ursachen und Folgen für die Langzeitstabilität von PV-Modulen (Mikro)

Supervisor:

Prof. Dr-Ing. habil. Raimund Rolfes

Researcher:

M.Sc. Roozbeh Nabavi

Duration:

2012-2016

Funded by:

German federal ministry of education and research (BMBF)

Brief description:

From the mechanical point of view, initiation and propagation of Micro-cracks in silicon wafers as the core part of an individual solar cell, responsible for electricity production, impels a critical limitation on durability of the photovoltaic (PV) module. In the context of Mikro-Projekt, ISD will develop a material model in order to capture the crack initiation and propagation in polycrystalline silicon wafers.

 

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Lifetime increase and lightweight design of rotor blades through nano-modified and hybrid materials (LENAH)

Bild zum Projekt Lebensdauererhöhung und Leichtbauoptimierung durch nanomodifizierte und hybride Werkstoffsysteme im Rotorblatt (LENAH)

Supervisor:

Prof. Dr-Ing. habil. Raimund Rolfes

Researcher:

M.Sc. Christian Gerendt

Duration:

2015-2018

Funded by:

Federal Ministry of Education and Research (BMBF)

Brief description:

The efficiency of wind energy turbines has to be increased in the near future. To achieve this goal, rotor blades have to be as large and light as possible, which can only be realized using modern composite materials. By applying numerical methods developed at ISD, highly efficient laminate compositions made from GFK, CFK and metal are identified to design rotor blades of high load ability, durability and low weight.

 

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