Active Structures and Noise Control Technical Group

2009 CAV Workshop

George Lesieutre Mary Frecker

Christopher Rahn

Aerospace Engineering Mechanical Engineering

The Pennsylvania State University

Updates on the Actuation of Miniature Trailing-Edge

Effectors

Michael Thiel

George A. Lesieutre

Sponsors: U.S. Army, NASA

Miniature Trailing-Edge

Effectors

• Static: Gurney flaps

– Small tab on lower surface of airfoil

– Increase sectional lift coefficient

• Dynamic : Miniature Trailing-Edge Effectors (MiTEs)

– Has potential to increase rotorcraft performance

– Distribute span-wise along rotor blade to delay stall

On/Off Deployment

Optimal deployment (for

greatest increase in lift)

is a square wave

Approximate as a 3-

term (plus offset)

Fourier series

For different duty cycles

– vary the magnitudes

Multi-Degree of Freedom Actuation

Design a piezoelectric (PZT) bimorph with

resonances at harmonics of the square wave

Should require low power and need no motion

amplification – direct drive

Able to design actuator with natural frequencies

at the 1st and 3rd harmonic – but drive voltages

exceeded PZT material limits

Minimization of Power Required

Second study to minimize power to create a 4 Hz square wave

1st natural frequency at the 3rd harmonic

Voltage drive below PZT limit

Built and tested

Fabricated Design

Acquire FRF then adjust magnitude and phase

based on the data

Able to approximate square wave

Drive within material limits

Reduction of High-Cycle Fatigue in Integrally Bladed Rotors

through Piezoelectric Vibration Damping and Control

Jeffrey L. Kauffman

George A. Lesieutre

Sponsor: NASA Glenn Research Center

Damping Motivation & Approach

Integrally bladed rotor (IBR) lifetime reduced by high-cycle fatigue cracks IBRs are single pieces of material with little

damping Increased turbomachinery efficiency

No added damping from friction interfaces

Periodic aerodynamic forcing inherent to turbomachinery (rotor/stator passes)

High-cycle fatigue reduction through piezoelectric vibration damping Passive and/or semi-active damping and control

Hybrid harvesting-switching approach

Significant damping system constraints Implementation in rotating frame

Preservation of aerodynamics & structural integrity

Survival in high temperature environment

Additional modeling concerns High modal density

Complex geometry

–Integrally Bladed Rotor

–Previous turbomachinery

design

Passive Damping

Piezoelectric material shunting Resistive: frequency dependent damping

Inductive: resonant (damped) absorber

Capacitive: frequency dependent stiffness

Each approach employs additional circuitry

Multiple approaches may be needed for damping of multiple modes Single material patch with switching for

several shunt topologies

Semi-active techniques as well

Advanced concepts Resonance frequency de-tuning

Hybrid harvesting-switchingCapacitive Shunt

Resistive Shunt

Implementation Considerations

Piezoelectric material is typically placed in high-strain region

Optimal placement is typically mode-dependent 2-stripe (2S) & 3-bending (3B) modes are current modes of interest

Material placement constrained by turbomachinery environment Embedded piezoelectric material

Composite blades

Initial placement determined by coupling coefficient Measure of total blade energy

conversion (here, strain-to-electrical)

Effects depend on blade rotation

Conclusions & Current State

Piezoelectric vibration damping can significantly enhance IBR lifetime Dramatically reduce high-cycle fatigue in blades

Preserve aerodynamic & structural integrity

Ensure IBR remains efficient & attractive compared to “previous design”

Initial experimental testing completed at NASA Glenn Research Center Resistive, capacitive, and inductive shunts tested

Blade with piezoelectric patch tested in dynamic spin rig Ensure integrity of blade/patch structure

Determine potential impact of shunted patch through coupling coefficient

Initial results show appreciable damping increases

Advanced testing is in progress (throughout May ’09) Resistive and inductive shunts in dynamic spin rig

Simple harvesting concepts in bench-top environment

Beyond specifics of damping system, significant areas of research remain Realistic placement of patches and circuitry

High-temperature materials and coatings

Power & data transfer from rotating frame

Fabrication and Design of Nanoparticulate enabled micro forceps

Team Members: Milton Aguirre, Gregory Hayes, Nick Antolino, Christopher Muhlstein, Becky Kirkpatrick, Donald

Heaney, Eric Mockensturm, Sanjay Joshi, Harriet Black Nembhard, Alan Snyder, James Adair, Dr. Mary Frecker

Departments of:

Materials Science and Engineering

Mechanical and Nuclear Engineering

Industrial Engineering

The Pennsylvania State University, University Park, PA, 16802 USA

Ceramic and Composite Materials CenterAn NSF Industry/University Cooperative Research Center

National Nanotechnology Infrastructure Network

Introduction: Motivation

Flexible Endoscope

Minimally Invasive Surgery: MIS

NOTESTM [4]

NOTESTM => Natural Orifice

Transluminal Endoscopic Surgery

2-3 working channels

ranging in Dia. 1-5 mm

Laparoscopy [1]

1) Eliminate external incisions

2) No cosmetic scaring

3) Shorter hospital stays

4) Decrease risk of infection

5) Reduced recovery pain

Advantages of NOTES

[2][3]

Laparoscopy vs.

Ports

Mold Infiltration

Gel Casting

Planarization

Mold Removal

Sintering

Final Parts

Mold Fabrication

Colloid

Preparation

Gel Casting

Preparation

Mechanical

StrengthPerformance Testing

Project Process Flow Diagram

Instrument Design (FEA)

(1) Mold FabricationUV

MaskUV Filter

SU8 moldAntireflective coatingAl2O3 Substrate

Cross sectional image of forceps mold

As received Tosoh zirconia

powder 60 m by DLS

Chemically Aided Attrition Milling

(CAAM) 3mol% Yttria stabilized Zirconia

Dispersed, CAAM Tosoh

3YSZ powder 45vol%

136nm by DLS

CA

AM

(2) Material Fabrication

(3) Mold Infiltration

Fabrication

The mold is Burned away and ceramic is

sintered in 1 firing cycle run.

(4) Mold Removal and Sintering

TimeTem

p

1400 C for 2 hrs

600 C for 2 hrs

Refractory Al2O3

SU-8 3YSZ SU-8

Refractory Al2O3

3YSZ

Instrument DesignStrength data, collected from Zirconia test bars, is used in an

optimization routine to determine optimal dimensions of the device.

Tool Operation:

As the sheath is

advanced forward, the

forceps arms displace

toward one another

producing a grasping

motion.

Contact Stress Relief:

The forceps design

features a gap to provide

stress relief as contact

occurs between the

forceps arms.

Outer SheathPoint of Contact

Tool Actuation

Finite Model of MesoForceps with

Dimensional Parameters

gap open

L1 L2

L

3

Design Optimization Results

An illustration of contact stress relief,

here contact occurs when the outer

sheath is located 60% along the total

length.

Contact Stress Relief

0

100

200

300

400

500

600

700

0 10 20 30 40 50 60 70

Ma

x. P

rin

cip

al S

tre

ss

(M

Pa

)

Percentage along L2 (%)

allow

Contact

Occurs

Aspect Ratio (L:w) = 45

L:w 13.5 mm: 0.3 mm 1.0 mm

Dia.

0.3 x

0.3 mm

2

m

m

Solid Model Assembly

Performance Plots?

0

5

10

15

20

25

30

35

40

45

50

0 500 1000 1500 2000 2500

As

pec

t R

ati

o (

L:w

)

Ultimate Strength (MPa)

0

1

2

3

4

5

6

7

8

0 500 1000 1500 2000 2500

Fo

rce

(N

)

Ultimate Strength (MPa)

Fabrication Results

Testing Results

x, y, & z axis

piezo-actuator

load cell

PC /

controllerMechanical

bend bar

Knife edge

loading

points

AcknowledgmentsThe Adair Research Group

The Frecker Research Group

PSU Nanofab Staff

Penn State MRI Nanofab: the Pennsylvania State University Materials Research Institute NanoFabrication Network

and the National Science Foundation Cooperative Agreement No. 0335765, National Nanotechnology Infrastructure

Network, with Cornell University.

CCMC Ceramics and Composites Materials Center:

NIH Grant Number R21EB006488 from the National Institute Of Biomedical Imaging And Bioengineering. The content

in this paper is solely the responsibility of the authors and does not necessarily represent the official views of the

National Institute Of Biomedical Imaging And Bioengineering or the National Institutes of Health.

NSF Grant Number IIP0637850

NSF – Penn State Cooperative Center

1. Tufts-New England, M. C., 2007, Laparoscopy: A Proven Alternative,

2. Kantsevoy, S. V., Jagannath, S. B., Niiyama, H., Chung, S. S. C., Cotton, P. B., Gostout, C. J., Hawes, R.

H., Pasricha, P. J., Magee, C. A., Vaughn, C. A., Barlow, D., Shimonaka, H. and Kalloo, A. N., 2005,

"Endoscopic gastrojejunostomy with survival in a porcine model," Gastrointestinal Endoscopy, 62(2), pp.

287-292.

3. Wirral Health Informatics Service, 2004, Acorn - Fundraising for Wiral Hospital NHS Trust,

http://www.helpwirralhospital.nhs.uk/campaigns/campaigns.asp

4. Fujinon, 2007, Fujinon Web Site, http://www.fujinon.co.jp/jp/news/icon/endoscope/eg-530n-h.jpg

References

A Bistable Mechanism for Chord

Extension Morphing Rotors

Terrence Johnson, PhD Candidate A

Mary Frecker, Professor B

Farhan Gandhi, Professor A

A: Dept. of Aerospace Engineering, University Park, PA

B: Dept. of Mechanical and Nuclear Engineering, University Park, PA

Actuation concept: use of bistable arc for chord extension

SparHub

Plate RollerArc

First Stable State

Second Stable State

Expected Chord Increase: 20 – 40 %

New Concept

Living hinge: flexural pivot with minute stiffness (modeled as a pin joint)

living

hinge

First Stable

State

Second

Stable State

livin

g

hin

ge

Types of bistable arcs

Continuous Arc

Continuous Arcs joined by Living Hinge

Does not need energy to hold in state

Expected to require less force to

initiate snap

Simple system

Arc Function

Actuator to the flat plate

Support aerodynamic and inertial loads

New Concept

Arc Benefits

Objective: develop a process to design bistable arcs

(various types) for chord extension in aircraft

Focus: Circular Arcs, Rotorcraft systems

Results

Arc Comparison using Abaqus

Study: Force, Energy vs. Displacement

Continuous arc requires larger snap-through

force and displacement

Results

Study: Snap-Through Load and Displacement vs. Curvature

Curvature , Arc Base

Redline: 23 N

Arc curvature , Snap-Through Load and

Displacement

Continuous Arc w/ living hinge, requires less

snap-through load and displacement

When centripetal load is applied, Snap-Through

Load and Displacement

Both arcs are suitable to support Centri. Load

Contact-aided Compliant

Cellular Mechanisms (C3M)

Vipul Mehta (ME)

Prof. Mary Frecker (ME)

Prof. George A. Lesieutre (AERO)

Background

Most engineering materials have a small elastically recoverable strain.

There is a need for high strain materials

Applications include morphing skin, armor, etc.

Global Hawk and a proposed morphing wing cross-section

Modulus and elastic strain

for various materials1

1 Henry, C., and McKnight, G., “Cellular Variable Stiffness Materials for Ultra-Large Reversible Deformation in Reconfigurable Structures,” in Proc. of SPIE 6170, 2006

0 5 10 15 20 25 300

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

xglobal (%)

/all

non-contact structure - bending stress

non-contact structure - axial stress

contact-aided structure - bending stress

contact-aided structure - axial stress

stress relief

18% to 27%

contact

Proposed Design

Results

Material StrainCellular structure

without contact

Contact-aided

cellular structure

3 % 18 % 27 %

1682 1927 2655 2755 3155 4082 4200 5391 68820

100

200

300

400

500

600

# of unit cells per unit area (1/m2)

Mass (

g)

Non-contact cells: feasible designs

Contact-aided cells: feasible designs

Non-contact cells: infeasible designs

Contact-aided cells: infeasible designs

Application of cellular structures to morphing skin. As the number of cells per unit area increases the structural mass decreases. In general, contact-aided designs have lower mass. Also there are more feasible designs using contact as compared to non-contact designs

Summary

Cellular structures bearing contact provides a huge elastically recoverable strain; as high as 100% more than the cellular structures without contact and almost 30 times the core material strain.

–1 mmOngoing work involves development of Zirconia based meso–scaled cellular structure to obtain a high strength and high strain material.

Piezoelectric Nano Air Vehicles

Hareesh K. R. Kommepalli, Andrew D. Hirsh, Christopher D. Rahn

Department of Mechanical and Nuclear Engineering

Dr. Srinivas A. Tadigadapa, Kiron Mateti

Department of Electrical Engineering

The Pennsylvania State University, University Park, 16802

T-Beam Actuators

T-beam provides two-axis (+/- in-plane and +/- out-of

plane) bending.

Out-of-plane web actuation used in demonstrator.

Fabricated T-Beams

● Diced device parameters: height, h = 1 mm

web width, b = 0.7 mm

length, L ≈ 19.0 mm

flange width, s = 4.4 mm

flange thickness, t = 167.8, 324.3, 523.5, 719.3 μm

● RIE etched device parameters:

height, h = 100 μm

length, L ≈ 8.0 mm

flange width, s = 6 mm

flange thickness, t = 83 μm

RIE Etched Beam Performance

0 50 100 150 200 250 3000

5

10

15

20

25

VW (V)

wL(

) (

m)

Theory

Experiment

Diced T-Beam Test Cases

Diced T-Beam Experimental Results

Clapping Wing NAV Design Using T-Beams

T-Beams

Pin

Hinges

Wing Rods

Demonstrator Design Evolution: Fuselage and Hinges

First Fuselage

Syringe Hinge Design

Pin Hinge Design

Flex Hinge Design

First Design with Dual Wing Rods

First Designs with Dual Wing Rods and Polymer Wings

Dual Syringe Hinge with Wings

Dual Pin Hinge with Wings

Clapping Wing Tabletop Demonstrator

Dual Pin Hinge with Polymer Wings

Demonstrator Videos

0.5 Hz

16 Hz

Future Design With Independently Actuated Wings

Conclusions

T-Beam piezoelectric actuators provide bimorph

actuation in-plane and out-of-plane.

T-Beam actuators can be fabricated using dicing or

RIE etching.

With four electrodes and +V, ground, and float

combinations, the best displacement configuration can

be determined.

T-Beam actuators can be used in a clapping wing NAV.

Wing motion of 30 degrees was demonstrated.

Future research: Design optimization and lift

measurement.