Structural Analysis & Active Materials GroupDept. of Mechanical Engineering & Aeronautics

IIMEC Related Activities of U. Patras on Multi-Functional Materials

Nikolaos A. Chrysochoidis

Research Fellow

Dimitris A. Saravanos Professor

Third Annual Meeting, Annenberg Presidential Conference Center, Texas A&M University, College Station, Texas 18-19 January 2012

Location

Patras

Olympia

Delphi

Mycenae

Student exchanges

Outline

Participation in Schools organized during the last year

Organization of International Conference ICAST 2011 supported by IIMEC

Other Research activities of University of Patras in the areas of IIMEC

Participation in Workshop organized at the field of wind energy - Egypt

Future Activities

Student exchanges

Outline

Participation in Schools organized during the last year

Organization of International Conference ICAST 2011 supported by IIMEC

Other Research activities of University of Patras in the areas of IIMEC

Participation in Workshop organized at the field of wind energy - Egypt

Future Activities

ICAST201122nd International Conference on Adaptive Structures Technologies

October 10-12, 2011Corfu, Greece

Conference Chair Dimitris Saravanos Professor, University of Patras

• Three Days• Two parallel sessions• 108 Participants • 3 keynote lectures• 65 Oral presentations• 38 Posters

Corfu Athens

Ascona

Paris

London

Rome

Berlin(Potsdam)

ICAST 2011 - Sessions

Sessions:• Multi functional materials• Morphing Structures• Semi- Active vibration control• Energy Harvesting and self-powered devices• Adaptive Wind Turbine Rotors• Active Contol• Damping• SHM• Actuation and Sensing Devices

ICAST 2011 - IIMEC Support

NAME ORGANIZATION City/Country     

IIMEC:    Brian Lester Texas A&M University College Station - USAJeffrey Kauffman The Pennsylvania State University Pennsylvania - USAMichael Pontecorvo Pennsylvania State University Pennsylvania USAEl bekkaye MERRIMI Université Mohammed V-Souissi Rabat-MoroccoDimitrios Chortis University of Patras Patras, GreeceAlexandros Solomou University of Patras Patras, Greece     USA:    Julianna Abel University of Michigan Ann Arbor - USAYa(Sophia) Wang Virginia Tech Blacksburg, VA - USAWonHee Kim University of Michigan Ann Arbor, USA     International:    

Peerawan Wiwattananon Delft University of Technology, Aerospace Engineering Delft - Netherlands

Paolo Basso University of Pavia Pavia - ItalyWander Vieira Rotorcraft Research Group- Carleton University Ottawa - CANADAHongli Ji Nanjing University of Aeroautics & Astranautics Nanjing - ChinaYuji Takada Aichi institute of technology Toyota - Japan

Shih-Chieh Lin Istitute of Applied Mechanics, National Taiwan University Taipei - Taiwan

Support of 15 students covering their registration and lodging expenses

ICAST 2011

• Three Days• Two parallel sessions• 108 Participants • 3 keynote lectures• 65 Oral presentations• 38 Posters

Student exchange

Outline

Participation in Schools organized during the last year

Organization of International Conference ICAST 2011 with the IIMEC Support

Other Research activities of University of Patras in the areas of IIMEC

Participation in Workshop organized at the field of wind energy

Future Activities

Lectures covered topics on :• Thermodynamics• Micromechanics• Homogenisation• Modeling & Characterization of SMA• Fatigue and Damage mechanics• Non Destructive Evaluation • Applications of SMA

Social Events:• Visit to Dodoni Theatre • Excursion to Zagorochoria (Monodendri) • Dinner at Mystagogia

University of Patras participated with two students: Konstantinos Georgopoulos-Bosinas and Thodoris Machairas having interactions with students from various nationalities.

Summer School

Winter School

IIMEC WINTER SCHOOLcomputational materials science across scales

January 8th-17th, 2012 in College Station, TX

Nikolaos Chrysochoidis attended to the Winter School thanks to the full IIMEC support

Students exchange

Outline

Participation on Schools organized during the last year

Organization of International Conference ICAST 2011 with the IIMEC Support

Other Research activities of University of Patras in the areas of IIMEC

Participation on a Workshop organized at the field of wind energy

Future Activities

Material Coupling Effects on Composite Structures

Objectives:– Model effects of coupling on blade

structural stiffness and damping

– Included into DAMPBEAM FE and Structural Dynamics code.

0 10 20 30 40 50 60 70 80 900.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

1.1

1.2

1st M

odal

Los

s F

acto

r (%

)

Ply Angle (degree)

Coupling NO Coupling

Material Coupling Effect on Gl/Ep Blade-Models with Various Ply Angle

Laminations at Girder

0 10 20 30 40 50 60 70 80 90-0.05

0.00

0.05

0.10

0.15

0.20

0.25

1st M

ode

Sha

peT

wis

ting

(θx)

/ B

endi

ng (

b y) A

ngle

P ly Angle (degress)

Coupling NO Coupling

Notable Results:Strong effect of coupling terms on blade mode shape.

The difference is eliminated at θ=00 and 900 where the material coupling effect is physically vanished.

Evaluated nonlinear effects on stiffness and damping of large blades

Chortis, D. I, and Saravanos, D. A., 2011, “Linear and non-linear coupled damped structural dynamics models

for large wind turbine blades”, International Workshop: Advanced Materials for Wind Turbine Blades, Cairo, Egypt.

Nonlinear Damped Structural Dynamics

0 2 4 6 8 10 12 14 160.0

0.1

0.60

0.65

0.70

0.75

0.80

Mod

al L

oss

Fac

tor

(%)

Angular Velocity (rpm)

1st bending 2nd bending

0 2 4 6 8 10 12 14 160.0

0.5

1.0

1.5

2.0

2.5 1st bending 2nd bending

Nat

ural

Fre

quen

cy (

Hz)

Angular Velocity (rpm)

Predicted Stiffening Effect due to rotational loads and gravity

Box-Section Girder Model of 54m WT blade

Objectives:Model nonlinear effects due to large displacements-rotations on blade stiffness and damping

New nonlinear damped beam Finite Element

Nonlinear DAMPBEAM code.

Fxcentrifugal

Fxgravity

Student exchange

Outline

Participation on Schools organized during the last year

Organization of International Conference ICAST 2011 with the IIMEC Support

Other Research activities of University of Patras in the areas of IIMEC

Participation on a Workshop organized at the field of wind energy

Future Activities

Student Exchange

TAMU visit:Duration: 3 months , 5 May to 5 August

• Subjects :

• 1D Users material Subroutine with thermomechanical coupling

A new 1D users material subroutine developed for the simulation of the SMA wires response taking into account the thermomechanical coupling in constitutive laws. The developed UMAT captures efficiently Sma’s thermomechanical response making the designing process of Sma wire actuator more effective. In this work Lagouda’s and coworkers Sma’s constitutive model is used.

• Back stress model

The Back stress model aims to capture the highly anisotropic transformation strain generation and recovery observed in actuator components subjected to common material processing and training methods.

Visitor: Alexandros SolomouPhd candidate at University of Patras, Greece

1D UMAT with thermomechanical couplingCOMPARISON OF COUPLED AND UNCOUPLED

MODEL

Back Stress Model

Step 2 : Applying Moment Step 3 : Adding axial force

Step 4 : Cooling of the specimen while the applied moment and axial force are remained constant in order to calculate the transformation strain

Step 5 : Heating of the specimen while the applied moment and axial force are remained constant

Experimental procedure

Step 1 : Training of the specimen under axial load

Training load affects the transformation strain that a material exhibits during actuation procedures. This effect is due to the internal stresses that are accumulated during training and their direction is strongly related to the type of training load. By implementing the back stress in the model we are trying to capture internal stress effects.

Motivation:

t 3 ( )

( )2 ( )

curH

σ + β

Transformation strain evolution equation

Transformation strain Magnitude

Transformation strain direction

: Back stress tensorβ

Back Stress Model (Continue..)

Eq

uiv

ale

nt

sh

ea

r tr

an

sfo

rma

tio

n s

tra

in

Tensile transformation strain

Outcome: An upcoming joint paper at the SPIE conference at March 2012 coauthored by Darren Hartl and Dimitris Lagoudas

Students exchange

Outline

Participation on Schools organized during the last year

Organization of International Conference ICAST 2011 with the IIMEC Support

Other Research activities of University of Patras in the areas of IIMEC

Participation on a Workshop organized at the field of wind energy

Future Activities

Structural Health Monitoring of Polymer Matrix CompositesNon linear Ultrasonics Technique

Objective: Development of a new Structural Health Monitoring methodology based on damage detection via non –linear wave modulation characteristics.

Results: Detection of Impact Damage

Experimental Setup for Impact Damage Detection in Composite Plates

Conclusions: Ability to reveal even small

damage sizes Efficient for all common damage

types of composites: Delamination Debondings Matrix cracks Single lap adhesive joints

Healthy

4J Impact load

Structural Health Monitoring of Polymer Matrix CompositesNon linear Ultrasonics Technique

Development of Morphing Chevron with SMA wires

• Implementation of constitutive model in Abaqus UMAT

• Primary FEA for proof of concept• SMA characterization• Detailed FE Analyses • Manufacturing & Testing of Adaptive strip

& full scale prototype

Framework

• Development of an adaptive chevron in order to reduce the noise levels during airplane’s operation.

• Chevron to move between two positions: • deformed during take off/landing (min

7degs penetration) • Open in cruising.

• Apply internal SMA wire actuators• Target shape: minimum of 7 degs tip

deflection

Objectives

>7o

Morphing Chevron

Adaptive StripAdaptive Full Scale Prototype

Students exchange

Outline

Participation on Schools organized during the last year

Organization of International Conference ICAST 2011 with the IIMEC Support

Other Research activities of University of Patras in the areas of IIMEC

Participation on a Workshop organized at the field of wind energy

Future Activities

Future ActivitiesOrganization of a School Related on Modeling of Wind Turbine Blades

• Participation of DTU Risø and Delft University• Possible participation of British University in Cairo

University of Patras

National Technical University of

Athens

Center of Recycled Energy Sources

Topics• Modeling tools for Wind

Turbine Blades• Aeroelasticity• Damping • Non linear Effects• Design Optimization

Future Activities

Students Exchanges• Expected visit of one student from TAMU to University of

Patras to spend three months in Greece

• Visit of Thodoris Machairas at Tamu of three months from May to July 2012

Thanks for the Attention

Special thanks to the IIMEC institute

Questions?