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ADAPTIVE STRUCTURES AND NOISE CONTROLFaculty Members
• George Lesieutre• Mary Frecker• Chris Rahn• Zoubeida Ounaies• Reginald Hamilton• Kenji Uchino
Dr. Lesieutre projects• Piezoelectric-based Vibration Reduction of
Turbomachinery Bladed Disks via Resonance Frequency Detuning – NASA GRC; student: Jeff Kauffman
• Actuation of Miniature Trailing Edge Effectors for Rotorcraft – NRTC; student: Mike Thiel
• Multistate Fluidic Lag Damper– Lord Corp (w/ Smith); student: Conor Marr
• High-Strength High-Strain Structures Using Ceramic Cellular Contact-Aided Compliant Mechanisms (C3M)– NSF (w/ Frecker, Adair); student: Samantha Cirrone
2
k
short-circuitopen-circuit
Dr. Frecker’s research projects focus on optimal design & fab of compliant mechanisms for medical & aerospace apps
1 mm Compliant Forceps
Collaborators:Dr. J. Adair, MSEDr. C. Muhlstein, MSEDr. R. Haluck, SurgeryDr. A. Mathew, Gastroenterology
Students:Milton AguirreGreg Hayes
Sponsor: NIH NIBIB
Collaborators:Dr. J. Adair, MSEDr. G. Lesieutre, AeroE
Students:Vipul MehtaSamantha CironeGreg Hayes
Sponsor: NSF CMII
Cellular Contact-Aided Compliant Mechanisms
Collaborator:Dr. J. Hubbard, U. Maryland
Student: Yash Tummala
Sponsor: AFOSR
Compliant Spine for Passive Morphing of Ornithopter Wings
• High Performance Piezoelectric Actuators and Wings for Nano Air Vehicles
– AFOSR; Hareesh Kommepalli (PhD 2010), Mark Zhang (MS 2010), Kiron Mateti (PhD 2012), Rory Byrne-Dugan (MS 2012).
• Braille Display Using EAP– NIH; Paul Diglio (MS 2010), Thomas Levard (MS 2011), Michael Robinson (MS 2012).
• EFRI-BSBA: Learning from Plants – Biologically-Inspired Multi-Functional Adaptive Structural Systems
– NSF, Bin Zhu (PhD 2013)• LORD Rotorcraft Center Fellowship
– Lloyd Scarborough (PhD 2012)• Micro Air Vehicle Tether Recovery Apparatus
– AFOSR, Varma Gottimukulla (MS 2011)• Testing, Simulation and Control of Lead-Acid Batteries for Energy
Storage and Regenerative Braking of Hybrid Locomotives– DOE; Ying Shi (PhD 2012), Zheng Shen (PhD 2013), Chris Ferone (MS 2012).
• Development and Experimental Validation of an Electrochemical Control Model of Li-Ion Batteries for Hybrid Electric Vehicles
– Cummins Technical Center, Githin Prasad (PhD 2012).
Dr. Rahn – Mechatronics Research Lab
ADAPTIVE STRUCTURES AND NOISE CONTROLFaculty Members – Featured Research
• George Lesieutre• Mary Frecker• Chris Rahn• Zoubeida Ounaies• Reginald Hamilton• Kenji Uchino
Research in the ElectroactiveMaterials Characterization Laboratory
Zoubeida Ounaies and Group
+
Research Focus
Materials exhibiting electro-mechanical coupling, such as piezoelectric and ferroelectric ceramics, electro-active polymers, and nano-composites for sensing, actuation, electrical energy harvesting, conversion and storage
Health monitoring
Inflatable Antenna
Ultrasonic imaging
Capabilities for synthesis and fabrication
Fabrication
What we do…Develop, synthesize, process, and characterize new adaptive/smart materials
Structure-property relationship for Sensing-
Actuation-Storage
0 V 3 V
ACTIVE NANOCOMPOSITES: ENERGY HARVESTING AND STRESS GENERATION MEDIA FOR FUTURE MULTIFUNCTIONAL AEROSPACE STRUCTURES
Structure-Property Relationship for Sensor-Actuator-Storage
Limitations in Current ElectroactivePolymers (EAPs)
•Inadequate recovery force and work density
•Restricted operation temperatures and frequencies
•Limited development of additional ‘functionality’
•High activation voltages (low dielectric)
EAPFree
strain(%)
E(MV/m)
Polyurethane
Silicone
PVDF-based electrostrictors
PVDF and copolymers
11
100
5
<0.1
150
140
>10
>10
Current Soft Smart Materials: Limitations
Conflicting requirements!
Polymeric Advantages•Form, Shape,
Processing•Large deformation•Multiple Processes
• Introduce small amounts of nanoparticles to achieve dramatic changes in Mechanical, Thermal,
Physical, Electrical and / or Chemical Properties
• Establish a tool set for control of nanoparticledistribution: moving to spatially engineered and
designed nano-’composite’ material systems.
Approaches:
Technical Objectives:
• Control morphology of nanoparticles and polymer through processing andelectric field-tailoring to enable optimization of mechanical and electricalcontrast throughout the material, and thus increase “active” response.
• Elucidate critical aspects of the resulting structures to determine limitationsof nanoparticle-based enhancement of performance and enable novelactuation and energy harvesting.
Our Program: Objectives and Approach
Piezoelectric amorphous polymer (β-CN) APB-ODPA—Enhanced Piezoelectricity
Pr= ∆ε.ε0 .Ep
0
0.002
0.004
0.006
0.008
0.01
0.012
0.014
0.016
0 2 4 6 8 10 12
thickness strain for 0% and 0.1% SWNT in (b-CN)A/O at 10 Hz
out-o
f-pla
ne s
train
(%)
E(MV/m)
0.1%SWNT
0.0%SWNT
d33=6 pm/V
d33=20 pm/V
SWNT-Polyimide Piezoelectric polymer
+
O
CN
N
O
O
N
O
O
O O
n
O
CN
N
O
O
N
O
O
N
O
O
N
O
O
O O
n
Nanocomposites—Enhanced Electrostriction.
0.1% SWNT+ CP2
0.1% SWNT+ polar polyimide
2% SWNT+CP22% SWNT+ polar
polyimide0.26% SWNT+PVDF
Low E
Thickness strain, AC 1Hz
Nanocomposites—Enhanced Electrostriction.
0.1% SWNT+ CP2
0.1% SWNT+ polar polyimide
2% SWNT+CP22% SWNT+ polar
polyimide0.26% SWNT+PVDF
Low E
Thickness strain, AC 1Hz
•Presence of nanoparticles (such as SWNTs) created or enhanced an electrostrictiveresponse. Shown are the electrostrictive coupling coefficients for some of the polymer nanocomposites we developed.
•Achieved higher performance than other existing EAPS, such as PVDF and polyurethane.
Coefficient of Electrostriction
Advantage: Low driving electric fields and high effective dielectric constant
•We have quantified electrostriction performance and associated energy densities.•We have compared the response to state-of-the-art electromechanical actuators.
(PNCs from current study in yellow)
Addition of SWNTs creates a response at low fields with high energy density:
Processing Approach
Achieved good dispersion of nanoparticles in a variety of thermosetting and thermoplastic polymers:
In Situ PolymerizationUnder Sonication
9 months 1 year
0 min 7 hours
CP-2 (Polyimide)-SWNT, φc = 0.06 vol%
Direct mixing SWNT/Polyimide
In-Situ polymerization+Sonication
Impact on polymer morphology:
Impact on mechanical performance at low vol. % reinforcement better than Halpin-Tsai.
Impact on dielectric behavior at low vol. %
1 year0 min
Demonstrated that nanoparticles improve properties critical for electromechanical coupling:
% CrystallinityPure PVDF 47.284.6 vol% NanoSpheres 52.624.6 vol% NanoWhiskers 51.70
How It Works
-SWNTs are extensions of electrodes at high content: high local field increases polarization of mobile regions.
-“Nano-capacitive” network: high effective field for a given potential.
-Joule heating.
E (MV/m)0.0 0.1 0.2 0.3 0.4
Stra
in S
11
0.0000
0.0002
0.0004
0.0006
0.0008
0.0010
0.00120.1vol% SWNT0.5vol% SWNT1vol% SWNT2vol% SWNTPure CP2
Processing Anisotropy Leads to Bending Actuation
DC V
Only bends in one direction
0.5 vol%
0 V 1 V 2 V 3 V
• Functionally graded due to solution-casting
• Processing dependent performance
• Measured strain not material property but
“laminate” –“unimorph” response
Actual
Polymer skin
Surface Actuation of SWNT-CP2 Films via Resistive Heating
45 mm
45 mm
1 Hz
0.1 Hz
1 vol% SWNT-CP2
Vapp = 280 V AC → Eapp ~ 0.006 MV/mImax = 7.85 mA
Assume catenary shape: y = c cosh(x/c)→ Length of actuated sample (L) = 2(y2 – c2)1/2
Strain (ε) = (L – Lo)/Lo = 1.6%
IR image IR image
Tg (CP2) = 209 oC
σ (film) = 0.012 S/cm (in-plane)
Summary
• We have successfully demonstrated experimentalevidence of the creation of an electrostrictiveresponse in amorphous polymer nanocompositesby addition of small quantities of nanoparticles.
• Most importantly, these improvements wereachieved at much lower actuation voltages, andwere accompanied by increase in bothmechanical and dielectric properties.
• Our efforts reported herein provide new avenuesto significantly improve the electromechanicalresponse of EAP-based nanocomposites.
E (MV/m)0.00 0.05 0.10 0.15 0.20 0.25 0.30
Stra
in S
11
0.0000
0.0002
0.0004
0.0006
0.0008
0.0010
0.0012
0.00140.1vol% SWNT1vol% SWNT2vol% SWNT
E2(MV2/m2)
0.00 0.01 0.02 0.03 0.04 0.05
Stra
in S
11
0.0000
0.0002
0.0004
0.0006
0.0008
0.0010
0.0012
0.00140.1 vol% SWNT1 vol% SWNT2 vol% SWNT
(a)
(b)
Shape Memory Alloys: Material Design
Reginald F. Hamilton, PhDAssistant Professor of Engineering Science and
Mechanics
Spring Workshop of the CAV 2011
Spring Workshop of the CAV 2011
The SMA response is due to a solid-solid martensitic phase transformation.
Shape memory effect (SME)
Austenite is the high-temperature phase.
Martensite is the low temperature phase.
ΔTH represents the thermal hysteresis.
Strain, ε
Stress, Σ
Temperature, TSpring Workshop of the CAV 2011
Shape Memory Effect (SME): Deformation mechanism
Heat T > Af/Recover residual ε
CVP Reorientation
Σcr(M)
Austenite
Self-accommodated Martensite (SAM)
CoolT < Ms
Detwinning facilitates preferential Variant A
Inset images copied from Bellouard, Y. (2008) Mat Scie Engr A 481-482, pg 582
Spring Workshop of the CAV 2011
Psuedoelastic Effect (PE): Deformation at constant temperature T > Af
stress, Σ
strain, ε
AusteniteReverse MT complete
Σcr(F)
Σcr(R)
A
MartensiteVariant A
The value of the critical stress increases linearly with temperature.
Spring Workshop of the CAV 2011
Critical Stress is Temperature Dependent
SME
Spring Workshop of the CAV 2011
Non-Ferrous SMA Systems
Otsuka, K. and C. M. Wayman, Eds. (1998). Shape Memory Materials. Cambridge, Cambridge University Press.
Spring Workshop of the CAV 2011
High-Temperature SMA Systems
Firstov, G. S., J. Van Humbeeck, et al. (2004). "Comparison of high temperature shape memory behaviour for ZrCu-based, Ti-Ni-Zr and Ti-Ni-Hf alloys." Scripta Materialia 50(2): 243-248.
Spring Workshop of the CAV 2011
Magnetic Field Induced SMA Systems
Pons, J., E. Cesari, et al. (2008). "Ferromagnetic shape memory alloys: Alternatives to Ni-Mn-Ga." Materials Science and Engineering: A 481-482: 57-65.
Conditions for SME and PE
Spring Workshop of the CAV 2011
• SME and PE are realized if the MT is crystallographically reversible and slip does not occur.
• Alloys with ordered atomic structures and also exhibit a thermoelastic MT are favored for SME and PE.
• SME and PE responses depend on chemical composition, cold work, heat treatment, and thermo-mechanical cycling.
Spring Workshop of the CAV 2011
Classes of SMAs: Non-Ferrous SMAsMagnetic Field Induced SMAsHigh-Temperature SMAs
Applications of SMAs
Spring Workshop of the CAV 2011
• Free recovery– SMA element causes motion or strain
• Constrained recovery– SMA prevented from changing shape, and thus generates
stress
• Actuator, work production– work is done as motion occurs against a stress
• Energy storage, dissipation– pseudoelastic applications can involve the storage of
potential energy