structural analysis & active materials group dept. of mechanical engineering & aeronautics...
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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
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
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