Twelfth Engineering Mechanics Symposium · Twelfth Engineering Mechanics Symposium 5 Preface The Graduate School on Engineering Mechanics, a joint initiative of the Eindhoven and

Twelfth Engineering Mechanics Symposium 29 - 30 October 2009 De Werelt, Lunteren

Graduate School on Engineering Mechanics c/o Eindhoven University of Technology PO Box 513, building W-hoog 4.133 5600 MB Eindhoven NL Tel.: +31 40 2474060 Fax: +31 40 2447355 E-mail: [email protected] http://www.em.tue.nl

Colophon: Editor: J.A.W. van Dommelen Publication date: September 2009 Notice: An electronic version of this brochure will be available at: http://www.em.tue.nl

Twelfth Engineering Mechanics Symposium 3

Contents

Preface 5

1. Program 7

2. Keynote Lecture and Introduction to the Workshops 11

3. Introduction Presenters and Abstracts of Presentations 19

4. Survey of Poster Presentations 45

4 Twelfth Engineering Mechanics Symposium


Preface The Graduate School on Engineering Mechanics, a joint initiative of the Eindhoven and Delft Universities of Technology and the University of Twente, organizes on an annual basis the Engineering Mechanics Symposium. The aim of this symposium is to stimulate the communication and the exchange of information with respect to ongoing research in the field of Engineering Mechanics. To achieve this, the program contains a keynote lecture by a leading expert in the field, topical sessions in relation to the selected research program of the graduate school, poster presentations of actual research projects by PhD-students and a meeting of the senior academic staff. The Twelfth Engineering Mechanics Symposium takes place October 29-30, 2009 at De Werelt in Lunteren. In the opening session, Prof. Charbel Farhat from Stanford University will present a keynote lecture entitled: A Computational Framework Based on an Embedded Method with Exact Local Riemann Solvers for Fluid-Structure Interaction Problems with Large Motions and Deformations. Furthermore, four workshops are organized that partly run plenary and partly run in parallel. Topics of this year’s workshops are: • M2i

Organized by Han Huétink (UT, main organiser), Ron Peerlings (TU/e) and Sergio Turteltaub (TUD)

• Fluid-structure interaction Organized by Stefan Luding (UT, main organiser), Bert Roozen (TU/e) and Harald van Brummelen

(TUD) • MicroNed Organized by Fred van Keulen (TUD, main organiser), Yves Bellouard (TU/e) and André de Boer (UT) • Dynamics Organized by Rob Fey (TU/e, main organiser), Andrei Metrikine (TUD) and Richard Loendersloot (UT) The workshop organizers provide plenary introductions on the trends and challenges of the workshops. Two of those plenary introductions have been included in the morning program on the first symposium day, whereas the other two have been included in the morning program of the second symposium day. Next, two of the actual workshops have been scheduled to run in parallel on the first symposium day, whereas the other two have been scheduled to run in parallel on the second symposium day. Each workshop consists of two parts, separated by a break. Each part consists of 2 presentations by AIOs/postdocs. The duration of each of the AIO/postdoc presentations is 20 minutes and followed by 10 minutes of discussion. For the best AIO-presentation within each workshop a prize will be awarded. Winners will be announced directly before the closing of the symposium on Friday, October 30. Additionally, there are two poster discussion sessions in which PhD-students participating in the Graduate School on Engineering Mechanics present their current research project. In relation to these presentations a contest is organized in which a jury selects the best three contributions. This year’s members of the jury are: Prof. Miguel Gutiérrez (TUD), Ir. Henk Jan ten Hoeve (NLR), Dr. Varvara Kouznetsova (TU/e), and Prof. Stefan Luding (UT). Winners will be announced directly before the closing of the symposium on Friday, October 30. On Friday, October 30 a meeting of the senior academic staff participating in Engineering Mechanics takes place. This report contains more detailed information on the Twelfth Engineering Mechanics Symposium. Included are the following sections: • Section 1: Detailed program of the symposium • Section 2: Abstracts of the keynote lecture and introduction to the workshops • Section 3: Abstracts of presentations in the workshops and a short introduction of the presenters • Section 4: Survey of poster presentations



1 PROGRAM

This section contains the detailed program of the Twelfth Engineering Mechanics Symposium. Information on the keynote lecture and introductions to the sessions are presented in section 2. Abstracts of the presentations can be found in section 3.



Program Twelfth Engineering Mechanics Symposium

Thursday, 29 October 2009 10.00-10.30 Registration and Informal get-together Room Azië 10.30-12.40 Opening Session Room Afrika 10.30-10.40 Opening of the Symposium by Prof. Marc Geers 10.40-11.40 Opening lecture: "A Computational Framework Based on an Embedded

Method with Exact Local Riemann Solvers for Highly Nonlinear Multi-Phase Fluid-Structure Problems" by Prof. Charbel Farhat

11.40-12.10 Trends and challenges in “M2i”

by Prof. Han Huétink 12.10-12.40 Trends and challenges in “Fluid-structure interaction”

by Prof. Stefan Luding 12.45-13.45 Lunch 13.50-14.50 Workshops 1 and 2, part A Workshop 1: Room Afrika M2i

Workshop 2: Room Amerika Fluid-structure interaction

Xiao Ma (UT) Modelling friction in aluminium extrusion process

Francecso Pizzocolo (TU/e) A mixed hybrid formulation for 2D poroelasticity with discontinuity

Cem Tasan (TU/e) Micro-mechanical characterization of ductile damage in sheet metal

Stephan Hannot (TUD) A fully coupled FEM model of Electro-Mechanical-Fluidic interaction

14.50-15.50 Poster Discussion Session: Room Azië

Presentation of current research projects, carried out by PhD students and Postdocs participating in Engineering Mechanics

15.50-16.20 Break 16.20-17.20 Workshops 1 and 2, part B Workshop 1, cont’d: Room Afrika M2i

Workshop 2, cont’d: Room Amerika Fluid-structure interaction

Jingyi Shi (TUD) Discrete dislocation-transformation model for multiphase steels

Nicole Clerx (TU/e) Direct injection of steam in a cross-flow of water

Wouter Quak (UT) Meshless methods and forming processes

Arjan Schutte (UT) Contact induced vibrations and noise of rolling tyres

17.30-18.30 Poster Discussion Session II: Room Azië

Presentation of current research projects, carried out by PhD students and Postdocs participating in Engineering Mechanics

18.30-19.00 Informal reception 19.00-22.00 Dinner 22.00-24.00 Bar


Program Twelfth Engineering Mechanics Symposium

Friday, 30 October 2009 09.00-10.00 Plenary Session Room Afrika 09.00-09.30 Trends and challenges in “MicroNed”

by Prof. Fred van Keulen 09.30-10.00 Trends and challenges in “Dynamics”

by Dr. Rob Fey 10.00-11.00 Workshops 3 and 4, part A Workshop 3: Room Afrika MicroNed

Workshop 4: Room Amerika Dynamics

Emre Dikmen (UT) Multiphysical Effects on High Speed Mini Rotordynamics

Lotfollah Pahlavan (TUD) Identification of Multiple Cracks in Beam Structures

Marco Matteucci (TU/e) Up-concentration of bio-material with a magnetic microbead manipulator

Benjamin Biemond (TU/e) Nonsmooth bifurcations of equilibria in planar continuous systems

11.00-11.30 Break 11.30-12.30 Workshops 3 and 4, part B Workshop 3, cont’d: Room Afrika MicroNed

Workshop 4, cont’d: Room Amerika Dynamics

Nico van Dijk (TUD) A new discrete level-set-based topology optimization method

Ted Ooijevaar (UT) Vibration based Structural Health Monitoring and the Modal Strain Energy Method Applied to a Composite Beam

Mohammad Samimi (TU/e) An enriched cohesive zone model for delamination in brittle interfaces

Richard Ogink (TUD) A Wake Oscillator Model for the Modelling of Vortex Induced Vibration

12.35-12.50 - Announcement of winning contributions in the AIO/Postdoc

Presentation contest and in the Poster contest - Closure

12.50-13.50 Lunch 14.00-15.30 Assembly of Project Leaders EM Room Amerika 16.00-20.00 Meeting of EM Advisory Board De Lunterse Boer


2 KEYNOTE LECTURE

and

INTRODUCTION TO THE WORKSHOPS

This section contains abstracts of the Keynote Lecture by Prof. Charbel Farhat and Introductions to the workshops “M2i”, “Fluid-structure interaction”, “MicroNed”, and “Dynamics” by the session organizers.



Keynote Lecture

A Computational Framework Based on an Embedded Method with Exact Local Riemann Solvers for Highly

Nonlinear Multi-Phase Fluid-Structure Problems

Charbel Farhat

Vivian Church Hoff Professor of Aircraft Structures, Department of Aeronautics and Astronautics, Department of Mechanical Engineering, and Institute for Computational and Mathematical Engineering,

Stanford University, 496 Lomita Mall, Stanford, CA 94305-4035, USA This talk presents a computational framework for the solution of transient, highly nonlinear, high-speed, multi-phase fluid-structure interaction problems. To this effect, the context is set to that of the implosive collapse of a gas-filled underwater structure. This fluid-structure interaction problem is characterized by ultrahigh compressions, shock waves, large structural displacements and deformations, self-contact, and possibly the initiation and propagation of cracks in the structure. The development of a corresponding computational model is a formidable challenge. It requires accounting for all possible interactions of the external fluid — namely, water — the internal gas, and the given nonlinear structure. It also requires incorporating in the computations material failure models, and capturing the precise effects on the pressure peaks of many factors such as the rate of structural collapse, hydrodynamic instability at the fluid/bubble interface, and cavitation when it occurs in the external fluid. Many of these features also arise in the modeling of the extracorporeal shock wave lithotripsy procedure where shock waves are generated to break a kidney stone into small pieces that can travel more easily through the urinary tract and pass from the body. The key components of the described computational framework include: (a) an embedded multi-phase CFD (Computational Fluid Dynamics) method based on the exact solution of local, one-dimensional two-phase Riemann problems, (b) an effective tabulation and interpolation method based on truncated tensor products (sparse grid) for enabling the evaluation of the Riemann invariants and/or alleviating their computational cost, (c) an analytical approach for enforcing the kinematic transmission condition at the embedded fluid-structure interface, (d) an energy conserving algorithm for enforcing the equilibrium transmission condition at that same embedded interface, and (e) a staggered and yet numerically stable and time-accurate algorithm for efficiently time-integrating the coupled fluid-structure equations of equilibirum. Each of these computational topics is discussed in sufficient details with particular attention to achieving, wherever possible, second-order spatial and temporal accuracy. Finally, unique features of this computational framework are highlighted for several three-dimensional multi-phase fluid-structure interaction problems associated with underwater implosion.


Workshop 1

Materials innovation institute M2i

Han Huetink1, Ron Peerlings2, Sergio Turteltaub3

1University of Twente, Faculty of Engineering Technology

P.O.box 217, 7500 AE Enschede, The Netherlands, e-mail:[email protected]

2 Department of Mechanical Engineering, Eindhoven University of Technology, PO Box 513, 5600 MB Eindhoven, The Netherlands, e-mail: [email protected]

3Faculty of Aerospace Engineering, Delft University of Technology

Kluyverweg 1, 2629 HS Delft, The Netherlands, e-mail: [email protected]

The workshop on the Materials innovation institute (M2i) is intended to demonstrate the impact that the Engineering Mechanics Graduate School has had on the scientific development of novel materials and production methods. In 1997 the Dutch Ministers of Economic Affairs (EZ), of Education, Culture and Science (OCW), and of Agriculture , Nature Management and Fisheries (LNV) established four Leading Technological Institutes (LTI), as first presented in the policy document "Knowledge in Action" (Kennis in Beweging). One of these institutes is The Netherlands Institute for Metals Research, (NIMR). The other institues are: the Telematica Instituut, (TI), the Wageningen Centre for Food Sciences, (WCFS) and the Dutch Polymer Institute (DPI). Each LTI is a public-private partnership and is organised as a virtual institute: researchers in different knowledge institutes execute the scientific programme formulated in collaboration with the industrial partners. The LTI engage in fundamental strategic, i.e. pre-competitive research. After four years the institutes were evaluated. The evaluation committee concluded that in general the participating companies are satisfied that the LTI have generated increasingly focussed programmes that contribute to their competitiveness and innovative capabilities and meet their longer-term research needs. The LTI act as a “one stop shop” for the companies and within the network the contacts between companies have increased. In all cases the taxpayer’s money is well spent and the institutes are involved in research of a high standard. Based on this evaluation the ministries continued the financial support for another 6 years. In 2008 the new innovation program M2i is started together with the Ministry of Economic Affairs and all the industry and knowledge partners supporting M2i. During the launch event it was also announced that NIMR has changed its name into Materials innovation institute (M2i). In the M2i programme is expressed that “Our vision is to be the world-class institute for fundamental and applied research in the fields of structural and functional materials. By working closely together with high level academic and industrial partners, we deliver new materials for economic growth of our industry and for creating a sustainable society”, and “Our mission is to innovate our industry and society with new materials in a durable way”! The M2i research is organised in 8 clusters: 1 Virtual shaping and structural performance 5 Tailor-made high-performance steels 2 Multi-scale fundamentals of materials 6 Durability 3 Processing technologies of functional materials 7 Surfaces, interfaces and thin films 4 High-performance light-weight materials 8 Advanced joining and disassembly December 2008 104 researchers (PhD students and Post docs) were employed by M2i. About 20 of them are EM PhD students, mainly contributing to the clusters 1 Virtual shaping and structural performance and 2 Multi-scale fundamentals of materials. The workshop includes several examples of the research being conducted by EM students on M2i topics.


Workshop 2

Fluid-structure interaction

Stefan Luding1, Bert Roozen2, Harald van Brummelen3

1University of Twente 2Eindhoven University of Technology

3Delft University of Technology

An overview of the activities and challenges in Fluid Structure Interaction will be given. At the Dutch universities many several projects and activities are ongoing within EM but also outside, e.g., within the JMBurgersCentrum. Worldwide much more is going on, especially concerning modern solution methods for coupled problems like. Examples for various systems and problems will be given, before the Introduction is concluded with a short overview of the four EM-PhD talks that will follow.


Workshop 3

MicroNed

Fred van Keulen1, Yves Bellouard2 and André de Boer3

1 Department for Precision and Microsystems Engineering

Mekelweg 2, 2628CD Delft 2Eindhoven University of Technology

3University of Twente

MicroNed is one of the big research programs which have been funded by means of the revenues of the Dutch natural gas resources. The program has formally a research focus on microsystems. However, a closer look reveals that the research activities range from nanoscale devices and aspects up to macro-scale microsystems applications. Interesting, but also very hard to manage, is the fact that the research program is carried out by more than 30 partners, including academia and industry, the latter ranging from very small to big. In this presentation, an overview of the MicroNed program will be given. Special attention will be for the Fundamentals and Modeling Cluster (FunMod). The FunMod cluster is build upon three work packages, namely:

• Transport phenomena and multiphysics • MicroMechanics • Design & Optimization

Transport phenomena and multiphysics work package is a combination of two related research fields. The ‘transport phenomena’ part of the package is concerned with the modeling at micrometer scale of fluid and gas flows. The multiphysics part deals with interactions of different physical domains, again at the micro- and nano scales. The MicroMechanics workpackage places the focus on the engineering mechanics fundamentals of microsystems. Topics which are addressed include thin films, lifetime issues of thin films, surface and interface effects and buckling effects. The Design & Optimization workpackage deals with optimization and reduced modeling for microsystems.


Workshop 4

Dynamics

R.H.B. Fey1, A.V. Metrikine2, and R. Loendersloot3

1 Eindhoven University of Technology, Department of Mechanical Engineering, phone +31-(0)40-2475406, [email protected]

2 Delft University of Technology, Faculty of Civil Engineering and Geosciences, phone +31-(0)15-2784749, [email protected]

3 University of Twente, Faculty of Engineering Technology, phone +31-(0)53-4894463, [email protected]

In this presentation an overview is given of the current research in the field of (Structural) Dynamics within the Graduate School of Engineering Mechanics. A modest attempt is made to place this research in a broader perspective. As will become clear, the research field Dynamics finds wide application and in general has an interdisciplinary character. It is often combined with the research fields Acoustics, Fluid Mechanics, Materials, Control, Mechanical Design, Optimization, and Electrical Engineering. Research in the field of Dynamics at the Delft University of Technology (TUD): • In the Engineering Dynamics group of the department Precision and Microsystem Engineering at the

TU Delft, current research focuses on numerical methods for model reduction, operational modal analysis techniques, multifield simulations and multibody dynamics. Their generic expertise is used to tackle applications in microsystems, wind energy, bicycle and car dynamics.

• Projects at the Faculty of Civil Engineering and Geosciences in the research groups Wave Mechanics and Computational Mechanics: dynamics of high-speed railway tracks, dynamics of offshore risers, ice-induced vibrations of offshore structures, dynamic fracture of concrete at high loading rates, multi-scale numerical analysis of the dynamic failure of materials.

• Current research in the Aerospace Structures group of the Faculty of Aerospace Engineering involves development of both semi-analytical approaches and finite element based reduction methods in order to analyze the dynamic stability and large amplitude vibrations of composite shells. In addition computational tools for structural health monitoring of shells are developed; appropriate spectral methods including wavelet-based methods are used for dynamic analysis.

At Eindhoven University of Technology (TU/e), the current activities of the Dynamics & Control (D&C) group, part of the Department of Mechanical Engineering, in the Dynamics field are: • Nonlinear dynamics: modeling and analysis of multiphysics dynamic (micro-)systems with a current

focus on micro-electromechanical systems, dynamic stability of thin-walled structures using semi-analytic and experimental techniques, control and bifurcation analysis of non-smooth dynamic systems, chatter control in high speed milling, and robotic systems.

• High-tech systems: development of dynamic structural models and sensing methods for next generation flexible wafer stages.

• Structural acoustics for active and passive noise reduction: tire-road modeling for tire-road noise predictions, near-field acoustic holography (sound imaging), active suppression of thermo-acoustic instabilities in heating systems, design of multilayered combined active-passive cover systems.

• Vehicle dynamics: tire road contact modeling, truck modeling, active cabin suspension, vehicle safety.

Finally, an overview is given of the activities in the research field Structural Dynamics at the Faculty Engineering Technology of the University Twente (UT). The four groups Structural Dynamics & Acoustics (SDA), Production Technology (PT), Surface Technology and Tribology (STT), and Mechanical Automation (MA) are organized in the Institute of Mechanics, Processes and Control Twente, and interact in the following projects and/or topics: • SDA-PT. Condition monitoring based on vibrations and ultrasonics, impact behavior on composites. • SDA-STT. Contact dynamics: surface roughness, wear, noise, tire road interaction, friction during

forming processes. • SDA-MA. Active and passive vibration control for high-speed and high-accuracy applications: control

& actuation, rotor dynamics, shape morphing, power harvesting for smart structures, robotics and machine dynamics, laser welding.

• PT-STT-MA. Ultrahydrophobic surfaces using femtolaser technology: self cleaning surfaces, de-icing systems on aircraft wings.

• SDA. Optimization of complex dynamic structures.



3 INTRODUCTION PRESENTERS

AND

ABSTRACTS OF PRESENTATIONS

This section contains abstracts of presentations at the Twelfth Engineering Mechanics Symposium. Abstracts are in alphabetic order on the (first) author. Abstracts of the keynote lecture and an introduction to the workshops are presented in section 2.



Short Introduction speakers at the 12th Symposium of the Graduate School on Engineering Mechanics (in alphabetic order)

Abstract title: Nonsmooth bifurcations of equilibria in planar continuous systems Workshop: Dynamics Biemond, J.J.B. (Benjamin) Eindhoven University of Technology, Department of Mechanical Engineering, Section Dynamics and Control Advisor: Prof.dr. Henk Nijmeijer Co-advisor: Dr.ir. Nathan van de Wouw

Biography and description of research: Benjamin Biemond is a PhD 2-student, who started his project in March 2009. He is working on an NWO-funded project, entitled "Stability, Bifurcations and Stabilisation of invariant sets in differential inclusions." The aim of this project is twofold. First, theoretical results are pursued on the stability of this class of dynamical systems. These results may be used to obtain control strategies achieving asymptotic stability. Second, bifurcations are studied that are induced by the discontinuous behaviour of the systems. Other participants: University of Groningen

Abstract title: Direct injection of steam in a cross-flow in water Workshop: Fluid-structure-interaction Clerx, N. (Nicole) Eindhoven University of Technology, Department of Mechanical Engineering, Section Process Technology Advisor: Prof.dr.ir. J.J.H. Brouwers Co-advisor: Dr.ir. C.W.M. van der Geld

Biography and description of research: Nicole Clerx is a fourth year PhD student in the Process Technology group at the Mechanical Engineering Department of the TU/e. The aim of her project is to experimentally investigate the turbulent mixing and heating phenomena induced by the condensation of steam in a cross-flow of water. The experiments are carried out in a closed loop, in which the steam is injected perpendicularly into the water that circulates under actively controlled temperature and pressure conditions. Particle Image Velocimetry, high speed imaging and resistance thermometers are applied to obtain time-averaged velocity and temperature data as well as visualisation images of the mixing process of the condensed steam and the bulk water. The outcome of these experiments is used to validate a new physical model that simulates the rapid heating of fluids and will be applied in, for instance, the food industry for the design of a new generation of steam injectors and sterilizers. The research is performed in cooperation with NIZO Food Research and Stork and is funded by STW.


Abstract title: A new level-set-based topology optimization method Workshop: MicroNed Dijk, N.P. van (Nico) Delft University of Technology, Faculty of Mechanical, Martime and Materials Engineering (3mE), Department of Precision and Microsystems Engineering (PME) Advisor: Prof.dr.ir. Fred van Keulen Co-advisor: Dr.ir. Matthijs Langelaar EM research theme: Reliability and Optimization

Biography and description of research: Nico van Dijk is 3rd year PhD. student at the research group Fundamentals of Microsystems. This project within MicroNed started in mid 2007 and has been all about improving our abilities to apply optimization techniques in an early stage of microsystem design. Especially topology optimization methods are promising because of their design flexibility. Especially in the field of multiphysics optimal designs can be very unintuitive. Therefore this research is aimed at level-set methods for their potential of treating problems with multiple physical domains. Nico finished his MSc. degree at the Faculty of Aerospace Engineering in Delft in collaboration with the research institute TNO on the subject of damage mechanics in crash simulations. His solid background in computational mechanics allows him to look at the mathematical optimization methods with an engineering perspective.

Abstract title: Multiphysical Effects on High Speed Mini Rotordynamics Workshop: MicroNed Dikmen E. (Emre) University of Twente, Mechanical Engineering Department Advisor: Prof.dr. André de Boer; Co-advisor: Dr.ir. Peter van der Hoogt, Prof.dr.ir. Ben Jonker, Dr.ir. Ronald Aarts EM research theme: Structural Dynamics and Control

Biography and description of research: Emre Dikmen obtained M.Sc. degree from Koc University, Istanbul,Turkey in 2006. After his graduation he joined to Structural Dynamics and Acoustics group at University of Twente as a PhD Researcher. His research involves modeling multiphysical effects on high speed micro/ mini rotors and validating these models.


Abstract title: A fully coupled FEM model of Electro-Mechanical-Fluidic interaction Workshop: Fluid-structure interaction Hannot, S.D.A. (Stephan) Delft University of Technology, Faculty of Mechanical, Maritime and Materials Engineering (3ME), Department of Precision and Microsystems Engineering (PME) Advisor: Prof.Dr.ir. Daniel J. Rixen

Biography and description of research: Stephan Hannot is a 3rd year PhD. student within the research group Engineering Dynamics. He started his project in November 2006. His research is part of the MicroNed program which is one of the BSIK projects of the ministry of economic affairs. His project is related to the multiphysical modeling of Microsystems and focuses on the Finite Element modeling of electrostatically actuated MEMS. Of special interest for hem are: solution procedures for static and dynamic problems and modeling fluid film damping. For modeling this fluid film damping he is especially interested in including the full non-linear Reynolds equation and deriving the coupled tangent matrices.

Abstract title: Modelling friction in aluminium extrusion process Workshop: M2i Ma, X. (Xiao) University of Twente, Surface Technology & Tribology

Biography and description of research: Ir. X. Ma joined the Surface Technology & Tribology group in University of Twente as a PhD researcher in February, 2007, after graduating as Master of Metallurgy in University of Sheffield. The current project concerns establishing a physical model that is capable of predicting surface quality of aluminium extrusion products so that extrusion conditions and process parameters can be tailored and optimized.


Abstract title: Up-concentration of bio-material with a magnetic microbead manipulator Workshop: MicroNed Matteucci, M. (Marco) Eindhoven University of Technology, faculty of mechanical engineering

Biography and description of research: Marco Matteucci conceived a PhD in “Nanotechnologies addressed toward medical applications” at the University of Trieste in March 2007 with a research theme entitled “Biological and medical applications of Deep X-Ray Lithography and LIGA technique”. He was appointed as a post-doc researcher in the Micro- and Nano- Scale Engineering group (MNSE) at Tu/e in May 2008. His project is in the framework of the cluster SMACT II-C-5 of the MICRONED network. The aim of his project is to design, fabricate and characterize a microsystem that will allow up-concentration of diluted biological samples through superparamagnetic bead actuation. Such a microsystem has the scope of enabling the detection of specific bio-mass in diluted samples for medical purposes.

Abstract title: A Wake Oscillator Model for the Modelling of Vortex Induced Vibration Workshop: Dynamics Ogink, R.H.M. (Richard) Delft University of Technology, Faculty of Civil Engineering and Geosciences, Offshore Engineering Group Advisors: Prof.dr. A.V. Metrikine, Prof.ir. J. Meek

Biography and description of research: Richard Ogink is a Phd candidate at the TU Delft. His Phd research is a cooperation of the Section of Structural Mechanics and the Offshore Engineering Group. The aim of this project is to develop an oscillator model that can describe the lift force due to vortex shedding on a circular cylinder that is placed in a flow; and to describe, with this model, the vortex induced vibration of long cylindrical structures.


Abstract title: Vibration based Structural Health Monitoring and the Modal Strain Energy Method Applied to a Composite Beam Workshop: Dynamics Ooijevaar, T.H. (Ted) University of Twente, Faculty of Engineering Technology Advisor: Prof.dr.ir. R. Akkerman, Prof.dr.ir. A. de Boer EM Reseach theme: Structural Dynamics ad Control

Biography and description of research: Ted Ooijevaar is a PhD student at the University of Twente in the Production Technology Group. His work is performed in close collaboration with the Structural Dynamics & Acoustics Group. He started his PhD in October 2009, after graduating on the same subject: Vibration based Structural Health Monitoring. He presented this work during his graduation project at the SAMPE Benelux student conference, the SAMPE Europe student conference and the 15th International Conference on Composite Structures in Porto (June 2009). Development of Structural Health Monitoring technologies for composite based structural components for aircrafts is one of the objectives of the European research program Clean Sky / Eco–design. An increase of the part’s service life reduces its cost and long term ecological impact. Vibration based damage identification methods are promising as an alternative for the time consuming and costly Non–Destructive Testing methods currently available. The change of the dynamic properties is employed to identify damage such as delaminations. The objective of the research is to develop methods to identify and localise damage in composite aircraft structures. Participants in the Eco-Design Project: EADS, Fraunhofer institute, Stork Fokker, Snecma, Dassault Aviation, Agusta Westland, Eurocopter, NLR, TU Delft, University of Twente

Abstract title: Identification of Multiple Damages in Beam Structures Workshop: Dynamics Pahlavan, L.P. (Pooria) Delft University of Technology, Faculty of Aerospace Engineering Advisor: Prof.dr. Zafer Gürdal Co-advisors: Ir. Christos Kassapoglou and Dr. Eelco L. Jansen EM research theme: Computational and Experimental Mechanics

Biography and description of research: Pooria L. Pahlavan is a 2nd year PhD student of the research group “Aerospace Structures (AeS)” who has started his project in August 2008. His research is a part of the research area “Structural Health Monitoring (SHM)”. The primary goals of the project are damage detection and force history identification in thin-walled composite structures. Determination of the remaining service life of structures in order to replace scheduled maintenances with as-need ones is also being pursued as the secondary goal of the project. The methods developed are based on propagation of ultrasonic waves in structures as waveguides and studying the additional reflections from discontinuities. The focus is on the inverse solution of the wave equation derived for damaged structures using the wavelet transform. Pooria has his BSc and MSc in Mechanical Engineering from Ferdowsi University of Mashhad, Iran. However, he is extremely satisfied with getting involved in Aerospace applications. His present interests are SHM and system identification.


Abstract title: A mixed hybrid formulation for 2D poroelasticity with discontinuity Workshop: Fluid-structure interaction Pizzocolo, F. (Francesco) Technology University of Eindhoven, Department of Biomedical Engineering Advisor: Prof.dr. K. Ito Co-advisor: Dr.ir. J.M. Huyghe, Dr.ir. J.C. Remmers

Biography and description of research: Francesco Pizzocolo is a 2nd year PhD student in the BMT group “Orthopaedic Biomechanics” at the TU/e. He started is project in June 2008. The goal of his research is to design a model which describes the behavior of a fracture in a 2D porous medium. The subject of this project is crucial for understanding and predicting the physical behavior of many systems of interest (from Biology to Soil mechanics or Petroleum Engineering). The project focuses on two main questions: what happens precisely at the crack tip that causes propagation of the crack in a fluid-saturated medium and what is the role that the fluid flow inside the cavities has in the propagations of the cracks.

Abstract Title: Meshless methods and forming processes Workshop: M2i W. Quak (Wouter) University of Twente, Department of Mechanical Engineering Advisors: Dr.ir. A.H. van den Boogaard and Prof.dr.ir. J. Huétink EM research theme: Computational and Experimental Mechanics

Biography and description of research: Since September 2007, PhD researcher Wouter Quak is working on the investigation and application of meshless methods in forming processes. The goal of the project is to find a meshless strategy that is a good alternative to the finite element method in simulating large deformation bulk forming processes. Current research is focusing on the stability of meshless methods in geometrical non-linearity and incompressibility.


Abstract title: An Enriched Cohesive Zone Model for Delamination in Brittle Interfaces Workshop: MicroNed Samimi, M. (Mohammad) Department of Mechanical Engineering, Eindhoven University of Technology Advisor: Prof.dr. Ir. M.G.D. Geers Co-advisor: Dr.ir. J.A.W. van Dommelen

Biography and description of research: Working on the ‘interfacial delamination in integrated microsystems’, Mohammad Samimi started his Ph.D. in the group of mechanics of materials in the mechanical engineering department of TU/e in July 2006. His current research involves the numerical simulation of delamination in brittle interfaces which are quite likely in microsystems. Application of a novel enrichment to conventional cohesive zone models in order to avoid computationally expensive mesh refinements associated with such models has been carried out. Extension of the proposed enrichment to mixed-mode delamination problems is in progress.

Abstract title: Contact induced vibrations and noise of rolling tyres Workshop: Fluid-structure interaction Schutte, J.H. (Arjan) University of Twente, Faculty of Engineering Technology Advisor: Prof.dr.ir. A. de Boer Co-advisor: Dr.ir. Y.H. Wijnant EM research theme: Structural Dynamics and Control

Biography and description of research: Arjan Schutte is a PhD student at University of Twente in the Structural Dynamics and Acoustics Group. He started his research in April 2007. The objective is to develop numerical tyre/road noise models with emphasis on contact modelling and sound radiation. Traffic road noise is considered as an environmental problem and effective countermeasures are needed to reduce noise. For cars tyre/road noise is the main noise component above speeds of about 40 km/h. Tyre/road noise is generated through the interaction between a rolling tyre of a vehicle and the road surface. Many different mechanisms contribute to the generation of tyre/road noise. Because most generation mechanisms originate from the contact region, modelling of the interaction between tyre tread and road surface is crucial for an accurate prediction of the noise. With such a complete model, one can study the effect of modifications to the tyre or road, and ultimately design quieter tyre/road combinations. Other Participants: This CCAR project is a cooperation between University of Twente, TNO and Apollo Vredestein B.V.


Abstract title: Discrete dislocation-transformation model for multiphase steels Workshop: M2i Shi, J. (Jingyi) Delft University of Technology, Faculty of Aerospace Engineering Supervisors: Dr. S.R. Turteltaub, Prof. dr. ir. R. de Borst

Biography and description of research: Jingyi has just fulfilled her PhD study in Aerospace Engineering in Delft University of Technology. Her PhD research is related to the transformation induced plasticity (TRIP) steels. TRIP steels provide a good combination of strength and ductility due to martensitic transformations and plastic deformations. A discrete dislocation-transformation model was developed to study the TRIP effect at sub-grain length scales. The model can capture the complex interaction between transformations and plasticity.

Abstract title: Micro-mechanical characterization of ductile damage in sheet metal Workshop: M2i Tasan, C. (Cem) Eindhoven University of Technology, Department of Mechanical Engineering Advisor: Prof.dr.ir. M.G.D. Geers Co-advisor: Dr.ir. J.P.M. Hoefnagels

Biography and description of research: Cem Tasan is an M2i PhD researcher working in the group of prof. Marc Geers (Mechanics of Materials), in Mechanical Engineering Department of TU/e. His project, which was started in November 2005, is on the development and application of new experimental techniques to characterize deformation-induced ductile damage evolution in sheet metal. The motivation arises from the recent reports on unexpected failures in new high strength steel and aluminium alloys, limiting their use in especially automotive applications. The main aims in this route are to improve the understanding of physical damage micro-mechanisms, and to enhance the predictive capabilities of forming simulations by providing reliable damage evolution parameters.


Nonsmooth bifurcations of

equilibria in planar continuous systems

J.J. Benjamin Biemond, Nathan van de Wouw,

Henk Nijmeijer

Eindhoven University of Technology, Department of

Mechanical Engineering Dynamics and Control, P.O. Box 513, 5600 MB Eindhoven

phone +31 (0)40 247 4092, email [email protected]

Important properties of dynamical systems are limit sets, such as equilibria or limit cycles. Limit sets can change in character, appear, disappear, or gain or lose stability when a system parameter is changed. Such changes are related to bifurcations. For the class of planar continuous nonsmooth systems, we study what limit sets can appear or disappear during a bifurcation of an equilibrium. In planar continuous, nonsmooth systems one can identify a number of curves in state space, called boundaries, where the differential equation is locally nonsmooth. Away from these boundaries, the vector field is locally smooth. In literature, bifurcations are studied where an equilibrium point coincides with a single boundary, that is a locally smooth curve in state space. In this presentation, we study the bifurcations of equilibria in planar continuous, nonsmooth systems. We investigate the case where the bifurcating equilibrium coincides with multiple boundaries, that are not required to be smooth curves in state space. In that case, multiple limit cycles and equilibria can be created or destroyed in a bifurcation. An approach is presented, that can be used to analyse all possible bifurcations. Hereto, the dynamics in a neighbourhood of the bifurcating equilibrium are approximated with a conewise affine system. This system is studied in two steps. First, the dynamics at the bifurcation point is studied, where the dynamics is piecewise linear in cone-shaped domains. The stability of an equilibrium of this system is studied and necessary and sufficient conditions are presented for asymptotic (or exponential) stability of an equilibrium point in conewise linear systems. Second, using this stability result, a procedure is presented in [1], that identifies all limit sets that are created or destroyed at a bifurcation of an equilibrium. These limit sets contain equilibria, closed orbits, and homoclinic and heteroclinic orbits. Existing equilibria, homoclinic and heteroclinic orbits of the conewise affine system are found in a trivial manner. To find all possible closed orbits, return maps are studied. To make it computationally feasible to find all fixed points of these maps, new theoretical results are presented. With the presented procedure a complete identification is obtained of the limit sets, that appear or disappear in the discontinuity-induced bifurcation of the equilibrium of the planar conewise affine system. This bifurcation accurately describes the bifurcation in the original planar nonsmooth system. Furthermore, the procedure can accurately identify the occurrence of multiple limit cycles. The theoretical results and the procedure are illustrated by means of an example. [1]

Biemond, J.J.B., van de Wouw, N., Nijmeijer, H. (2009) Nonsmooth bifurcations of equilibria in planar continuous systems, submitted to Nonlinear Analysis, Hybrid Systems


Direct injection of steam in a

cross-flow of water

N. Clerx

Eindhoven University of Technology, Department of Mechanical Engineering,

Section Process Technology, P.O. Box 513, NL 5600 MB Eindhoven Phone +31-(0)40-2475906, e-mail [email protected]

Direct steam injection is a very effective way to rapidly and homogeneously heat fluids. A well-known industrial application is the sterilization process of milk. To improve the taste of the milk it is necessary to decrease the heating time and increase the process temperature during sterilization. A CFD model, based on Large Eddy Simulation and Diffuse Interface Modeling, is being developed to facilitate the determination of the optimal process conditions and the scale up from laboratory experiments to commercial production scales. Next to that, an experimental study is conducted to investigate the turbulent mixing and heating phenomena induced by the condensation of steam in a cross-flow of water. For the experimental study, a dedicated set-up has been designed and built. This set-up is a closed loop in which water circulates at actively controlled temperature, pressure and flowrate. The measurement section of the set-up has a square crosssection of 30x30 mm2 and is optically accessible for application of several measurement techniques. Two-dimensional velocity fields near the steam injection location are measured by means of Particle Image Velocimetry. The temperature of the water near the steam injection location is measured at various points in the cross-section by three small traversing Pt-100 sensors. Next to that, the interface topology of the condensing steam jet has been investigated using a high speed camera at various steam mass fluxes, water temperatures and flowrates. Figure 1 shows the intermittent steam pocket growth and subsequent condensation, typically observed at moderate mass fluxes of steam. The findings of the experimental work are also used for the validation of the CDF model.

Figure 1: Consecutive recordings showing a typical break-up and subsequent condensation of a steam pocket at a moderate mass flux of steam. The time increment between two consecutive recordings is 0.3 ms.


A new discrete level-set-

based topology optimization method

N.P. van Dijk, M. Langelaar and F. van Keulen

Delft University of Technology

Keywords: topology optimization, level-set method, multiple constraints, sensitivity analysis, implementation Level-set based topology optimization approaches are gaining popularity due to their clear design description and potential for more natural treatment of multi-physics problems involving interfaces between physical domains. However, algorithms published in the literature have proven to be highly sensitive to the exact formulation and implementation used. In particular, a good definition of the design velocity, the driving force behind a level-set based optimization, is essential for proper functionality of the method. This design velocity is based on shape-sensitivity analysis and formulated as a continuum expression. How to exactly discretize this expression is often ambiguous. Moreover, a good formulation incorporating multiple constraints into the definition of the design velocity is often omitted. Therefore, we propose a new definition and implementation of the discrete level-set method and compare it with the shape-sensitivity-based formulation. This new formulation eliminates the inconsistencies by relating the design velocity to the sensitivities of the discrete system to the discrete level-set nodal values. Numerical examples demonstrate the effectiveness of the approach and its ability to treat multiple constraints in a satisfactory way.


Multiphysical Effects on High Speed Mini Rotordynamics

E.Dikmen, P.J.M. van der Hoogt, R. Aarts, B. Jonker, A. de Boer

University of Twente, Chair of Structural Dynamics and Acoustics,

P.O. Box 217, 7500 AE Enschede, The Netherlands, Phone: +31-(0)53-4893405, email: [email protected]

Introduction There have been recent developments on the high speed micro rotating machinery. However classical rotor dynamic modeling approaches can not be applied directly for designing these machines due to additional effects becoming crucial at micro level. These multiphysical effects, such as the interaction with the surrounding air and thermal effects should be taken into account while examining the rotor dynamic behavior. Theory In this research work thermal and flow induced effects on rotor dynamics for turbulent flow have been studied. Since the flow is turbulent, inertial effects as well as viscous effects become significant. In this study flow induced forces are implemented to the rotor’s finite element model as a spring-damper and added mass at each node. Finite element modeling of the rotor is based on Timoshenko beams (including the flexibility of the rotor shaft) and each element has four degrees of freedom at each node. As the rotation speed increases, the heat loss due to air friction and the temperature increase in the air gap between rotor and stator becomes more significant. Consequently the change of air properties due to this temperature change in the air gap should be considered when calculating the flow induced forces. Therefore a thermal model has been established in order to calculate the heat dissipation and the temperature increase in the air. In this model the rotor, stator and the gap in between are modeled as lumped thermal networks and the required convective heat transfer coefficients and heat dissipation are calculated by empirical correlations. Next the new air gap temperature is used to calculate the flow induced forces with updated air properties. In this way thermal and fluid effects in medium gap confinements are coupled with the rotordynamic models and their effects on critical speeds and vibration response can be properly investigated. Experiments An experimental setup has been built in order to study the support flexibility and multiphysical effects on the dynamics of mini rotors and to validate the theoretical model. Modal analysis of individual components and the complete setup have been performed to identify the dynamic characteristics. Spectrum maps are plotted in order to determine the onset of instability. Fair agreement between theoretical and experimental results has been observed.


A fully coupled FEM Model

of Electro-Mechanical- Fluidic interaction

Stephan Hannot and Daniel Rixen

Delft University of Technology, Faculty of 3ME, Department of Precision and Microsystems Engineering, Section

Fundamentals of Micro Systems, Mekelweg 2, 2628 CD Delft, the Netherlands Phone +31 (0)15-27 81881, e-mail [email protected]

A specific type of Microsystems or MEMS is the so called RF-MEMS switch. In contrast to MEMS resonators switches generally do not operate in a vacuum. Therefore at the small scales of MEMS fluid (or air) damping is the most dominant damping form. This means that if one is interested in transient or frequency behavior a proper damping model is required. This presentation uses the non-linear Reynolds equation to model the squeeze film damping. Advantages and drawbacks are provided. The formulation is provided ready for FEM implementation. Also a full linearization of the coupled equations is derived. The equations are tested on a model of simple micro switch. The results show that with this model it is possible to predict the damped motion as well as the frequency behavior. The frequency results also show that damping shifts the zero frequency point away from the pull-in point.

Fig. 1: geometry

Fig. 2: transient behavior Fig. 3: Pressure at F Fig. 4: Deformation at F


Modelling friction in aluminium

extrusion process

X. Ma

University of Twente, Surface Technology & Tribology

In aluminium extrusion process, high pressure between the bearing and extrudate results in very large friction and thus contact is of completely plastic state. When this happens the conventional “individual summits” approach of modeling friction tends to overestimate the friction stress. A load dependent friction model is developed, based on a cluster of summits, i.e. “contact patches”, instead of individual summits, to model the friction in aluminium extrusion.


Up-concentration of bio-material

with a magnetic microbead manipulator

M. Matteucci, F. G. A. Homburg, S. van Pelt, A. H. Dietzel

Eindhoven University of Technology, Department of mechanical engineering, section of Energy Technology, group

of Micro- and NanoScale Engineering, P.O. Box 513, NL 5600 MB Eindhoven phone +31-(0)40-247-5223 e-mail: [email protected]

In present times, manipulation of micron-sized beads with magnetic properties is widely used for separation of biological samples with volumes up to few ml. Actuation through external fields also makes magnetic bead manipulation very promising technique for several applications in the fields of microfluidics, Micro Electro-Mechanical Systems (MEMS) and Bio-MEMS [1][2][3]. Within this framework, a large number of applications regards the use of magnetic beads in sensing of biological material. Fast and reliable sensing is sometimes difficult because the concentration of the species that have to be detected is below the detection limit. For this reason, an up-regulation of species with a low concentration is required for more precise and reliable results. In order to collect and up-concentrate a quantity of bio-material (DNA, RNA) sufficient for detection, our goal is to manipulate functionalized super-paramagnetic beads in a microfluidic circuit. We will hear treat in detail the fabrication of our microfluidic and magnetic system. Moreover, a comparison between the simulations and the first experimental data for bead and capture will be discussed.

Figure 1. Comsol™ simulation of the number density of superparamagnetic beads with a 1 μm diameter captured by a Ni pillar with a 125 μm diameter. The simulation combines the effect of the flow and of the external magnetic field on the Ni pillar. Results show that a higher bead concentration (brighter areas) is present in the front of the pillar.

References: [1] S. H. Lee, D. van Noort, J. Y. Lee, B.-T. Zhang and T. H. Park Lab Chip, 2009, 9, 479–482. [2] R. J. S. Derks, A. H. Dietzel, R. Wimberger-Friedl, M. W. J. Prins Microfluid Nanofluid (2007) 3:141–149 [3] Q. A. Pankhurst, J. Connolly, S. K. Jones and J. Dobson. J. Phys. D: Appl. Phys. 36 (2003) R167–R181


A Wake Oscillator Model for the Modelling of Vortex Induced

Vibration

Richard Ogink

Delft University of Technology, Faculty of Civil Engineering and Geosciences, Offshore Engineering Group, Stevinweg 1, 2628 CN Delft, e-mail: [email protected]

Due to the depletion of onshore and nearshore oil and gas reservoirs, offshore hydrocarbon production advances into increasingly deeper waters. Hydrocarbon production in deep water takes place at floating production platforms. Transport of oil and gas from the reservoir below the seabed to the platform at sea level is facilitated by steel vertical pipelines that are known as risers. For deep water projects risers can have a length of more than 1000 meters and a diameter of 40 to 70 centimeters. Since floating platforms lack a support structure, risers of floating production systems cannot be clamped to a fixed structure and are able to oscillate freely under influence of currents and platform motions. Fatigue is therefore a major design concern. A key contributor to the fatigue of risers is vortex-induced vibration. A sea current flowing about a riser separates from the riser and vortices are formed in the downstream wake. The alternate shedding of these vortices results in an oscillating lift force that forces the riser from side to side across the wake. This phenomenon is known as vortex-induced vibration (VIV). The shedding frequency of the vortices follows the Strouhal relation and increases with increasing flow velocity. When the vortex shedding frequency approaches a resonance frequency of the riser, the amplitude of riser vibration starts to increase. As the amplitude increases, the flow around the riser begins to be influenced more and more by the motion of the riser. The vortices along the length of the riser are forced to be shed in phase, resulting in even larger lift forces and vibration. Now, the vortex shedding frequency violates the Strouhal relation and locks onto the resonance frequency of the riser, thereby sustaining violent vibration of the riser in a wide range of flow velocities. Deepwater risers have a dense spectrum of resonance frequencies due to their immense length of often more than 1000 meters. Additionally, they are often subject to sheared currents, of which the flow velocity varies along the riser. This implies that a number of resonance frequencies of such a riser are excited simultaneously by the flow. There is no consensus among researchers as to how many of these frequencies will be perceptible in the spectrum of VIV. There exists no reliable procedure to predict VIV of deepwater risers. Computational fluid dynamics codes fail to cope with flows about offshore risers, because of the relatively high Reynolds numbers of these flows, which are in the order of 104 to 106. Empirical prediction codes use experimental data obtained from tests with rigid cylinders vibrating at a single frequency. This implies that no mode interaction is accounted for in these codes, which is a serious drawback in application to deepwater risers. In this project vortex-induced vibration of deepwater risers is studied theoretically by employing a wake oscillator model. Wake oscillator models use a system of coupled nonlinear partial differential equations to describe the interaction of riser and wake. A novel approach is used in which the coefficients of the wake oscillator model are determined on the basis of hydrodynamic force measurements as function of the vibration frequency of the riser. This approach gives a description that takes into account the history of the flow that cannot be captured with commonly employed approaches.


Vibration based Structural Health Monitoring and the Modal Strain

Energy Method Applied to a Composite Beam

T.H. Ooijevaar, R. Loendersloot, L.L. Warnet, A. de Boer and R. Akkerman

Institute of Mechanics, Processing and Control – Twente (IMPACT) Section Structural Dynamics and Acoustics, University of Twente

P.O. Box 217, 7500 AE Enschede, The Netherlands phone +31 53 4892426, email [email protected]

Development of Structural Health Monitoring technologies for composite based structural components for aircrafts is one of the objectives of the European research program Clean Sky / Eco–design. An increase of the part’s service life reduces its cost and long term ecological impact. Vibration based damage identification methods are promising as an alternative for the time consuming and costly Non–Destructive Testing methods currently available. The change of the dynamic properties is employed to identify damage such as delaminations. Localization of damage in a carbon fibre reinforced composite is added to the damage detection research of Grouve et al.[1] by implementing the Modal Strain Energy [2]. The main issue addressed is the number of measuring points required to detect and localize the damage in a three dimensional component. This will set the requirements to the method or devices employed to obtain the dynamic response. The structure investigated here is a composite T-shaped stiffener section. This type of stiffener is frequently used in aerospace components to increase the bending stiffness of the component without a severe weight penalty. Recently, a new type of stiffener was developed by Stork-Fokker AESP, in collaboration with the Dutch National Aerospace Laboratories (NLR). This type of stiffener connection is referred to as a T-joint. This paper addresses the experimental work performed at the University of Twente. One meter long T-beams of 16 layers of carbon fibre reinforced PEKK, both intact and with a predefined delamination were manufactured by Stork Fokker AESP. A test set-up is developed to measure the vibrations with a laser-vibro meter. Validation of the method and verification of the numerical model developed are the key issues. The numerical model is discussed in more detail in Loendersloot et al. [3]. [1] W.J.B. Grouve, L.L. Warnet, A. de Boer, R. Akkerman, J. Vlekken, Delamination detection with fibre Bragg gratings based on dynamic behaviour, Composite Science and Technology, 68(12), 2418-2424 (2008) [2] N. Stubbs, J.T. Kim, K. Topole, An efficient and robust algorithm for damage localization in offshore platforms, Proceedings of the ASCE 10th Structures Congress, 543-546 (1992) [3] R. Loendersloot, T.H. Ooijevaar, L.L. Warnet, A. de Boer, Vibration based structural health monitoring in fibre reinforced composites employing the modal strain energy method, 3rd International Conference on Integrity Reliability and Failure, CD Proceedings, (2009) Acknowledgements The authors would like to acknowledge Stork Fokker AESP, and in particular J. Teunissen and H. Wiersma, for the manufacturing of a number of T--beam specimen.


1 2

x1 x1 x 2x 2

xx

y c x c

3 41 2

x1 x1 x 2x 2

xx

y c x c

3 4

Figure 1. Modeling an open-edge crack

Identification of Multiple Cracks in Beam Structures

L. P. Pahlavan

Delft University of Technology, department of Aerospace Engineering

Kluyverweg 1, 2629 HS Delft, the Netherlands phone: +31 (0)15 2787308, Email: [email protected]

Abstract Analysis of wave propagation and study of the behavior of the incident and the reflected mechanical waves in thin-walled structures has become the subject of intense research in the past few years as it relates to damage and force history identification in structural health monitoring (SHM) applications. Principally, due to the high frequency content of the generated waves in SHM applications, the mathematical model of the structure must be capable of accurate simulation of the higher vibration modes. Accordingly, approximate solution methods like conventional Finite Elements (FE) should be replaced by exact solutions over the spatial variables in order to capture the high frequency response of the structure. An appropriate method should be also able to perform an inverse analysis in a straight-forward manner. In the present study, in order to solve the governing equation of a bounded 1-D waveguide exactly, Daubechies compactly supported wavelets have been used [1] to form the transformation operators. The longitudinal propagation of high-frequency waves in a beam structure has been simulated by decoupling and solving the transformed equation. The equations are arranged in a Finite Element framework so that if there is a discontinuity in the structure, the increased number of nodes and elements needed to construct the system model can be introduced. This approach has been employed for open-edge non-propagating cracks as depicted in Figure 1 using fracture-mechanics formulas. Having derived the model of a cracked element, the displacement response of a sample beam having several different cracks is simulated as shown in Figure 2. Additional reflections due to the crack can be observed in this figure. In the next step, the performance of the developed model in solving the inverse problem has been evaluated. The cracks could be determined successfully using the force history and the stored values of the displacement response of the system from the previous forward solution. Although the solution of the inverse problem is not necessarily unique, the developed damage detection algorithm can accurately identify the cracks of any size or location. The excellent performance of the method even in the presence of 10% noise makes this a very promising approach in dealing with SHM problems. References [1] Daubechis I., 1992, “Ten lectures on wavelets”,

CBMS-NSF series in applied mathematics, SIAM, Philadelphia

Figure 2. Displacement response of (a) an un-damaged and (b) a damaged beam with 3 cracks

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A mixed hybrid formulation for

2D poroelasticity with discontinuity

F. Pizzocolo1, J.M. Huyghe1, J.C. Remmers2, K. Ito1, R. de Borst2

1 Department of Biomedical Engineering, TU/e 2 Department of Mechanical Engineering, TU/e

In the last decades, porous media research focused on applications of geomechanics. This enabled to achieve important goals in many fields of geo-sciences: petroleum engineering (logging technologies, bore hole instability, CO2 sequestration), soil mechanics (instability of slopes, instability of soils under tunneling), durability of materials (moisture transport). In the recent years the focus of the research about porous media is extending to biology. In fact, all the biological tissues are porous media. To understand the behavior of human tissues, it can be extremely helpful to prevent and treat many diseases related to, for example, blood perfusion, bones (osteoporosis), spine (herniation, low back pain). This project focuses on the intervertebral disc (IVD), that, for its properties, must be treated as a porous medium. The presence of damage, such as cracks, faults, and shear bands, can markedly change the physical behavior of the disc and affects his capacities of providing flexibility to the spine and absorbing and transmitting loads. We are developing a model which describes the behavior of a fracture in a 2D porous medium. As measurements in living humans are complex, finite element models have become an important tool of study load distribution in healthy and degenerated disc [2]. The project will zoom into what happens precisely at the crack tip. Near the tip the stresses are elevated above the average stresses. In order to predict propagation and, with that, structural failure, it is necessary to model what happens at the crack tip correctly. Fluid and solid are so strongly coupled that if fluid flow is not predicted in the right way, the model will predict wrong deformations and with that stresses and therefore propagation. The presence of the fluid relaxes the stress but can also cause stress. In our model, the saturated porous media are modeled as a two phase mixture composed of the deforming solid skeleton and the saturating pore fluids. To numerically simulate the interaction of the skeleton with the fluid, the media are modeled as porous continua, in which a representative element volume around any mathematical point in the media is always assumed to contain the solid phase and the fluid phase. It's been developed a mixed hybrid formulation for 2D poroelasticity with discontinuity. This formulation assembles the major properties of the mixed hybrid formulation with Lagrange multipliers [1] (approximation of the fluid flow fulfills the mass conservation equations locally, simultaneously approximations of flows and pressures) and of the Partition of Unity framework [3] [4] (discontinuities and singularities are modeled through local enrichment, continuity along the crack surface is preserved, discontinuities are introduced in a mesh-free way). References [1] K. Malakpoor, E.F. Kaasschieter, J.M. Huyghe. Mathematical modelling and numerical

solution of swelling of cartilaginous tissues. Part II: Mixed-hybrid finite element solution. ESAIM, 41:679–712, 2007.

[2] J.M. Huyghe, J.D. Janssen . Quadriphasic mechanics of swelling incompressible porous media. Int. J. Engng Sci., 35:793–802, 1997.

[3] J.J.C. Remmers. Discontinuities in materials and structures: a unifying computational approach. PhD thesis, University of Technology of Delft, 2006.

[4] F. Kraaijeveld, Propagating discontinuities in ionized porous media. PhD thesis, University of Technology of Eindhoven, 2009.


Meshless Methods

& Forming Processes

W. Quak, A.H. van den Boogaard and J. Huétink

Institute of Mechanics, Processing and Control, University of Twente

P.O. Box 217, 7500 AE Enschede, The Netherlands phone +31 (0)53 4894069, e-mail [email protected]

Introduction Finite element simulations of large-deformation bulk forming processes in a Lagrangian formulation can be problematic. When simulating for instance an extrusion or forging process, re-meshing or decoupling the elements from the deforming material is necessary. It is expected that meshless methods avoid these mesh-related problems and can be a good alternative to the finite element method for this type of problems. Meshless methods Many meshless methods have been proposed since their start in the 1980’s. One thing all methods have in common is that their shape functions are not based on a user-defined mesh. A result of this mesh independent definition of the shape functions is that during a large deformation process, the nodal connectivity can change. If the nodes start moving, their connectivity will change and therefore has to be updated during the simulation. This process of updating the connectivity is avoiding the problem of mesh distortion. Results In the current research a set of meshless shape functions is combined with a nodal integration scheme. Due to this nodal integration scheme the convection or mapping of state variables becomes superfluous since material points and nodes are at the same location. To avoid stability problems that can occur with nodal integration, a stabilized variant has been implemented. Firstly the scheme is tested in elasto-plasticity. The results are compared to a finite element solution. Secondly, the behavior of the scheme is examined in a large deformation setting.


An enriched cohesive zone

model for delamination in brittle interfaces

Mohammad Samimi, Johannes A.W. van Dommelen, and Marc G.D. Geers

Department of Mechanical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands, e-mail: [email protected]

Cohesive zone models have the appealing feature of predicting both delamination initiation and growth. However, application of these models to brittle interfaces is accompanied by some numerical difficulties. The oscillatory load-displacement behavior that is often observed for such interfaces is an artifact of the relatively coarse mesh size (with respect to interface parameters) and can break down the computations unless complicated path-following techniques are employed [1]. On the other hand, using a sufficiently refined mesh so that the separation field of a cohesive crack is approximated with acceptable accuracy, results in a noticeable increase in the size of the computations. Application of an enhancement to the conventional model considerably increases the robustness of cohesive zone models, thereby avoiding an expensive mesh refinement [2]. To this purpose, an adaptive hierarchical extension is presented to enrich the separation approximation in the process zone of a cohesive crack. In the proposed formulation, the linear separation approximation throughout the cohesive zone element is enriched by a piece-wise linear function. The finite element formulation of the enriched bulk and interface elements is elaborated and an adaptive strategy is used for a maximum efficiency. A numerical example shows that the proposed scheme improves the global load displacement response of the system discretized by a relatively coarse mesh without a need for further mesh refinement. In the formulation, the peak point of the additional interpolation function can be located at any arbitrary position within an interface element. The position and scaling factor used in this interpolation function are treated as additional degrees of freedom. The moving peak of the bi-linear function relates to the moving process zone and provides a more accurate numerical approximation of the physical problem where delamination grows in an interface. References [1] G. Alfano, M.A. Crisfield, “Solution strategies for the delamination analysis based on a combination of local-control arc-length and line searches”, Int. J. Numer. Meth. Engng, 58, pp. 999-1048, 2003. [2] M. Samimi, J.A.W. van Dommelen, M.G.D. Geers, “An enriched cohesive zone model for delamination in brittle interfaces”, Int. J. Numer. Meth. Engng, 2009.


Contact induced vibrations and noise of rolling tyres

J.H. Schutte, Y.H. Wijnant, and A. de Boer

Institute of Mechanics, Processing and Control – Twente (IMPACT) Section Structural Dynamics and Acoustics, University of Twente

P.O. Box 217, 7500 AE Enschede, The Netherlands phone +31 53 4893605, email [email protected]

In modern society, traffic noise has become an important issue. A significant contributor to traffic noise is tyre/road noise, which is caused by the interaction between tyre and road surface. Usually, distinction is being made between structural and aerodynamic generation mechanisms, although there is discussion on the relative importance of these mechanisms. For cars tyre/road noise is the dominant noise source for driving speeds greater than about 40 km/h. The main noise spectrum is in frequency range of 500 to 3000 Hz. In order to reduce tyre/road noise a thorough insight in the generation mechanisms and numerical models are needed. In order to predict and reduce tyre/road noise, different mathematical and empirical noise predicting models have been developed during the last decades. The main similarity between the mathematical models is that they can be separated in a tyre vibration model and a sound radiation model. Currently, because of the limited accuracy of the analytical models, the tyre vibration models tend towards numerical models based on finite elements. Finite elements are appropriate to model complex rubber material behaviour, tread profiles and detailed tyre constructions, and therefore resulting in more comprehensive tyre/road noise models. Since the interaction between tyre and road generates the noise, a correct modelling of the contact zone is important. The contact problem is non-linear and is best described in the time domain. In the finite element package Abaqus, implicit and explicit finite element models of tyres have been designed. The contact models consist of a contact condition, stating that the tyre cannot penetrate the road surface (hard contact), and a friction model. Different contact algorithms can be used to calculate the deformations and forces in the contact zone. A sound radiation model based on the boundary element method can be used to calculate the radiated tyre/road noise from tyre vibrations. Aerodynamic sources can be modelled as equivalent noise sources near the contact patch. Due to the geometry of a deformed tyre, the so-called horn effect amplifies the noise in the frequency range between 1000 and 2000 Hz. Acknowledgements The support of Apollo Vredestein B.V. and TNO within this CCAR project is gratefully acknowledged by the authors.


Discrete dislocation-transformation model for

multiphase steels

Jingyi Shi

Faculty of Aerospace Engineering Delft University of Technology Kluyverweg 1, 2629 HS Delft

The Netherlands

The interaction between martensitic phase transformation and plastic deformation in multiphase steels that contain grains of retained austenite is analyzed using a recently developed discrete dislocation-transformation model [1]. The model, which is used to study the transformation-induced plasticity effect at sub-grain length scales, consists of a combination of the discrete-dislocation method presented in [2] and a discrete transformation model. The model can capture the complex interaction between pile-ups at grain boundaries and the evolution of the microstructure due to transformation. Relevant microstructural factors that affect this interaction are analyzed, including grain-size, crystallographic orientation, volume fractions and grain connectivity. The simulations indicate that, as the average grain size decreases, the strengthening effect due to the martensitic transformation becomes increasingly ineffective, thus suggesting that the Hall-Petch effect is in fact detrimental for the transformation-induced plasticity effect. Further, it is found that the austenitic crystal orientation has a stronger effect on the plastic behavior than on the transformation behavior. On the other hand, the transformation rate depends on the connectivity of the austenitic grains and it is typically higher for connected grains compared to dispersed grains due to local interactions between transforming grains. References [1] Shi, J., Turteltaub, S., Van der Giessen, E., Remmers, J. J. C. (2008) A discrete dislocation-transformation model for austenitic single crystals, Modelling and Simulation in Materials Science and Engineering, 16 (5), DOI 10.1088/0965-0393/16/5/055005, Article Number 055005 [2] Van der Giessen, E. and Needleman, A. (1995) Discrete dislocation plasiticity: a simple planar model, Modelling and Simulation in Materials Science and Engineering, 3 (5), 689-735


Micro-mechanical characterization

of ductile damage in sheet metal

C.Cem Tasan, J.P.M. Hoefnagels, M.G.D. Geers

Eindhoven University of Technology, Department of Mechanical Engineering,

Section Materials Technology, P.O. Box 513 , 5600 MB Eindhoven, NL. phone:+31 40 247 2245, email: [email protected]

Triggered by the recent popularity of advanced high strength steels and aluminium alloys for weight-reduction in automotive components, industrial interest in deformation-induced damage in sheet metal is increasing in the last decades. Severe deformation during forming or service triggers different damage micro-mechanisms in these materials, leading often to unpredicted failures. These failures can be avoided by different strategies. From a metallurgical perspective, microstructures that are less susceptible to damage/failure can be investigated, which requires the identification of the underlying damage micro-mechanisms. From a more mechanical perspective, the predictive power of forming simulations can be enhanced, either by accurately measuring damage accumulation to tune-in the continuum damage models (CDM) or by developing new damage models based on experimentally identified damage micro-mechanisms. However, currently available experimental tools do not stand up to the above-mentioned critical experimental tasks. Therefore within this PhD project, new experimental methodologies are explored and/or developed that allow for:

(i) well-defined, multi-axial testing of sheet metal, (ii) accurate quantification of damage accumulation, (iii) characterization of the underlying physical damage micro-mechanisms,

in industry-relevant sheet metal. This presentation will give a brief overview of the achievements in these three routes.


4

SURVEY

of

POSTER PRESENTATIONS This section contains a survey of poster presentations of actual PhD-projects within the Graduate School Engineering Mechanics. Furthermore, poster presentations are available through:

http://www.em.tue.nl



Survey of Poster Presentations Twelfth EM Symposium Nr. Last name First name Univ. Title poster

1 Akcay Didem UT Updating the Craig-Bangton reduction basis for efficient structural optimization

2 Assaad Wissam UT Measuring the deflection of the die in aluminum extrusion 3 Beex Lars TU/e Cheap Use of Lattice Models 4 Bergers Lambert TU/e Time-dependent mechanics in metal-MEMS 5 Biemond Benjamin TU/e Nonsmooth bifurcations of equilibria in planar continuous systems 6 Boer Steven UT Elastic Hinge for Large Deflection 7 Boustheen Allwyn TU/e Layered modular polymeric laser structured μ-valve

8 Campen, van Julien TUD Stacking Sequence Design to Match Desired Lamination Parameters

9 Cloots Rudy TU/e Focus on Diffuse Axonal Injury 10 Coenen Erica TU/e Multi-scale modelling of localization and damage 11 Cornelissen Bo UT Analysis of yarn bending behaviour 12 Cracaoanu Ioan UT Friction in worn lubricated concentrated contacts 13 Del Tin Laura TUD Towards optimization of micro-Coriolis flow sensors 14 Dijk, van Nico TUD Discrete Level-set Topology Optimization 15 Dikmen Emre UT Multiphysical effects on high speed mini rotordynamics

16 Ertürk Isa TU/e Strain gradient crystal plasticity theory for time dependent behavior of thin metal films

17 Göncü Fatih UT Discrete Element simulation of granular materials 18 Grouve Wouter UT Optimising the production process of glass/PPS laminates 19 Haanappel Sebastiaan UT Joining of Thermoplastic Composites 20 Hadoush Ashraf UT Incremental forming by CBT 21 Hannot Stephan TUD Uncertainty and reliability for pull-in computations with FEM 22 Hartkamp Remco UT Anisotropic Lennard-Jones fluids in a nanochannel

23 Hilkhuijsen Peter UT Plasticity in Stainless steel and TRIP steel at non proportional strain paths

24 Hoitinga Wijnand TUD A-posteriori error analysis on a 1D Boltzmann equation

25 Irzal Faisal TU/e Finite strain formulation for propagating cracks in ionized porous media

26 Jong, de Pieter UT Power harvesting in helicopter rotor blades 27 Kampinga Ronald UT FEM for viscothermal acoustics

28 Karade Yogesh TU/e Guided Phase separation of polymer blend films on ion beam induced pre-patterned substrates

29 Khani Ali TUD Maximum Strength Design of Long Composite Non-Circular Cylinders

30 Kolluri Murthy TU/e Refinements to the Miniature Mixed Mode Bending (MMMB) Setup for Interface Delamination Characterization

31 Kooijman Jodi TUD Rider Motion Identification During Normal Bicycling By Means of Principal Component Analysis

32 Kurukuri Srihari UT Effect of temperature on anisotropy in forming simulations 33 Lutowska Agnieszka TU/e Model Reduction for Complex High-tech Systems 34 Ma Xiao UT Modelling friction in the bearing of aluminium extrusion process

35 Madani-Grasset Frédéric TU/e Micro-fabrication of multi-scale textured surfaces for water-repellent

applications 36 Meer, van der Frans TUD Capturing size effects in laminate failure 37 Neggers Jan TU/e Applicability of the Bulge Equations 38 Nguyen Vinh Phu TUD Numerical modelling of cement paste

39 Niazi Muhammad Sohail UT Plasticity induced anisotropic damage modelling for forming

processes 40 Nikbakht Mehdi TUD Automated modeling of discontinuities

41 Oelgaard Kristian TUD Optimisations of finite element tensors through automated code generation

42 Ogarko Vitaliy UT Data structure and algorithms for contact detection in numerical simulation of discrete particle systems

43 Ogink Richard TUD Vortex-Induced Vibration of Marine Risers

44 Ooijevaar Ted UT Vibration based structural health monitoring - modal strain energy method

45 Opstal, van Timo TU/e Stochastic Analysis of a Nonlinear Fluid-Structure Interaction Problem

46 Ozbek Muammer TUD Optical Monitoring of Wind Turbine Dynamics 47 Pahlavan Pouria TUD Identification of Multiple Cracks in Beam Structures 48 Paternoster Alexander UT Actuators for smart rotorblades


49 Perdahcioğlu Semih UT Utilizing the shape memory effect for self-healing of structures

50 Pina Juan Carlos TU/e Microstructure-based material model for thermo-mechanical fatigue of cylinder heads.

51 Pisarenco Maxim TU/e Simulation of Light Scattering from Gratings 52 Pizzocolo Francesco TU/e A mixed hybrid formulation for 2D poroelasticity with discontinuity 53 Quak Wouter UT Meshless Methods and Forming Processes 54 Rajesh Sheeba TU/e Towards fast femtosecond laser micromachining of glass 55 Rodriguez Natalia UT Friction modeling as a function of fiber orientation and fiber type

56 Rudnaya Maria TU/e Autofocus and Astigmatism Correction in Scanning Transmission Electron Microscopy

57 Sadeghian Hamed TUD Size Effects on Silicon Nanocantilevers

58 Sadeghinia Mahdi TUD Experimental Investigations on the Delamination of Metal-Oxide-Polymer Nano-Interfaces

59 Samimi Mohammad TU/e An enriched cohesive zone model for delamination in brittle interfaces

60 Schutte Arjan UT Contact induced vibrations and noise of rolling tyres

61 Shabir Zahid TUD Analysis of intergranular crack propagation in brittle polycrystals with a Generalized FEM and a network algorithm

62 Shan Xuming TUD Modelling of steam injection in porous media 63 Snippe Corijn UT Constitutive modelling of ALNOVI-1

64 Sridhar Ashok UT Surface modification techniques for improved adhesion between inkjet printed structures and PCB substrates

65 Steen, van der René TU/e Validation of steady-state handling characteristics of tyres

66 Steenhoek Alexander TUD Model Order Reduction techniques for multiphysical problems

67 Suarez Venegas

Daniel Ricardo TUD Uncertainties affecting orthopaedic (glenoid) implants' stability

68 Tabak Umut TUD Computational reduction in Vibro-acoustics 69 Tasan Cem TU/e Ghosts in Steels and their Influence on Mechanical Properties

70 Thuwis Glenn TUD Variable Stiffness Composite Skin for Next Generation Morphing High-lift Devices

71 Tiso Paolo TUD Reduced nonlinear modeling for MEMS dynamics

72 Valefi Mahdiar UT Surface-healing mechanism of CuO doped 3Y-TZP sliding against alumina

73 Veijgen Noor UT Skin Friction Measurement: whenever, wherever, whoever 74 Visser Roy UT Condition monitoring of uPVC gas pipes 75 Voormeeren Sven TUD Hybrid Dynamic Substructuring in Wind Turbine Engineering

76 Vreugd, de Jan TUD Effect of aging on mechanical properties of molding compound properties

77 Yadegari Varnamkhasti Sourena TUD Multiscale analysis of thermomechanical processes in metals

78 Yalcinkaya Tuncay TU/e Viscous Relaxation of Dislocation Sub-Structure Evolution

79 Yaqoob Muhammad Adeel UT Friction and stick-slip transition in vacuum and dry nitrogen: Single

asperity contact 80 Yazdchi Kazem UT Application of Delaunay Triangulation to discrete particle simulation 81 Zwieten, van Gertjan TUD Introducing the Embedded Discontinuity [ED] method 82 Arora Vikas UT Identification of oil-free bearing characteristics

83 Blom Agnes TUD Structural Performance of Fiber-Placed, Variable-Stiffness Composite Cylinders

Graduate School on Engineering Mechanics c/o Eindhoven University of Technology PO Box 513, building W-hoog 4.133 5600 MB Eindhoven NL Tel.: +31 40 2474060 Fax: +31 40 2447355 E-mail: [email protected] http://www.em.tue.nl

Documents

Twelfth Engineering Mechanics Symposium · Twelfth Engineering Mechanics Symposium 5 Preface The Graduate School on Engineering Mechanics, a joint initiative of the Eindhoven and