INPUTS FOR NASA ROAD MAP: Technology Area 12

AFOSR

10 March 2011

B. L. (“Les”) Lee, ScD Program Manager

Air Force Office of Scientific Research

Arlington, VADistribution A: Approved for Public Release.

Distribution is unlimited. AFOSR Case 11-17

2

PM: B. L. Lee (les.lee@afosr.af.mil)

BRIEF DESCRIPTION OF PORTFOLIO:

Basic research for integration of advanced materials and micro-

systems into future Air Force systems requiring multi-functionality

LIST OF SUB-AREAS:

Life Prediction (Materials & Devices);

Sensing & Diagnosis;

Micro-, Nano- & Multi-scale Mechanics;

Multifunctional Design (Shape Change);

Multifunctional Design (Property Tuning);

Self-Healing & Remediation;

Self-Cooling & Thermal Management;

Self-Sustaining Systems & Energy Management;

Precognition & Neutralization of Threats;

Engineered Nanomaterials

AFOSR PROGRAM OVERVIEW

3

Multifunctional Design

The objective of multifunctionality is improvement in system performance

Use system metric(s) to identify functions to combine and quantify gains.

General Rules:

Add functionality to material with most complex function-physics.

Target unifunctional materials/components operating in the mid-to-lower

functional performance regimes for multifunctional replacement.

Implement multifunctionality in the conceptual stage of system design.

Performance of multifunctional material/component may not be as good as its

unifunctional counterpart; irrelevant as long as system performance improves.

Strong/weak coupling between the multiple function-physics may or may not

exist and/or be important.

Multifunctional potential depends on sub-system interfacing capabilities and

function compatibility.

RESEARCH ISSUESGuest Lecture by Dr. J. Thomas - 2008 AFOSR M^4 Program Review

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• Increasing Emphasis on Multifunctional Materials

– Structural integration of electronic devices

– Combination of load-carrying capabilities with functional requirements (e.g. thermal, power)

– Adaptive, sensory and active materials

– Revolutionary concept of “autonomic” structures which sense, diagnose and respond for adjustment

– Hybridization of materials and lay-up for complex requirements

• Critical Needs for New Design Paradigm

– Physics-based multi-scale modeling

– Neural network and information science

– Design for manufacture

WHERE IS THE FIELD GOING? AFOSR Annual Review: 1 March 2005

5

VISION: EXPANDED

• site specific

• autonomic

AUTONOMIC

AEROSPACE

STRUCTURES

• Sensing & Precognition

• Self-Diagnosis & Actuation

• Self-Healing

• Threat Neutralization

• Self-Cooling

• Self-Powered

Biomimetics

Design for Coupled

Multi-functionality

Nano-materials

Multi-scale

Model

Micro- & Nano-

Devices

Manufacturing Sci

Neural Network &

Information Sci

6

7

VISION: EXPANDED

• site specific

• autonomic

AUTONOMIC

AEROSPACE

STRUCTURES

• Sensing & Precognition

• Self-Diagnosis & Actuation

• Self-Healing

• Threat Neutralization

• Self-Cooling

• Self-Powered

Biomimetics

Design for Coupled

Multi-functionality

Nano-materials

Multi-scale

Model

Micro- & Nano-

Devices

Manufacturing Sci

Neural Network &

Information Sci

11

FUNCTIONS OF INTEREST

Active Regulation

Reactive Materials

Mesoporous Networks

Adaptive Fluids/Solids

Self-Regulating

FunctionSelf-Generating

Function

BIO-INSPIRED SYSTEMS:BEYOND CURRENT VISION

7

8

NASA TA12 ROADMAP:Overarching Themes

• Multifunctional and lightweight are critical attributes

and technology themes required by mission

architecture pull.

• Certification, sustainment and reliability are technology

themes that are critical push technologies that address

mission gaps.

• We need to promote “game-changing” technologies

enabling future deep space missions, next-generation

aeronautic capabilities, and long-term space travel.

• Strategic roadmaps are available for each discipline of:

materials, structures, mechanical systems,

manufacturing and cross-cutting technologies.

9

NASA TA12 ROADMAP:Top Technical Challenges

• Radiation Protection (Top Challenge)

• Reliability (Top Challenge)

• Advanced Materials (Materials)

• Computational Materials (Materials)

• Multifunctional Structures (Structures)

• Virtual Fleet Leader (Structures)

• Mechanisms for Extreme Environments (Mech System)

• Precision Deployables (Mech System)

• Advanced Manufacturing Process Technology (Manuf)

• Sustainable Manufacturing (Manuf)

• Urban Infrastructure (Nat’l Challenge)

• Solar Energy (Nat’l Challenge)

• Building a Smarter Planet (Nat’l Challenge)

10

NASA TA12 ROADMAP:Top Technical Challenges

• Radiation Protection (Top Challenge)*

• Reliability (Top Challenge)

• Advanced Materials (Materials)*

• Computational Materials (Materials)

• Multifunctional Structures (Structures)*

• Virtual Fleet Leader (Structures)

• Mechanisms for Extreme Environments (Mech System)

• Precision Deployables (Mech System)

• Advanced Manufacturing Process Technology (Manuf)

• Sustainable Manufacturing (Manuf)

• Urban Infrastructure (Nat’l Challenge)*

• Solar Energy (Nat’l Challenge)

• Building a Smarter Planet (Nat’l Challenge)

* Multifunctional Design

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NASA TA12 ROADMAP:Focus Areas of Materials/Structures

Materials

• Lightweight structural materials

• Computational design materials

• Flexible material systems

• Environment (protection and performance)

• Special materials and processes

Structures

• Lightweight concepts

• Design and certification methods

• Reliability and sustainment

• Test tools and methods

• Innovative, multifunctional concepts

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Materials

• Lightweight structural materials*

• Computational design materials

• Flexible material systems*

• Environment (protection and performance)

• Special materials and processes*

Structures

• Lightweight concepts*

• Design and certification methods

• Reliability and sustainment*

• Test tools and methods

• Innovative, multifunctional concepts*

NASA TA12 ROADMAP:Focus Areas of Materials/Structures

* Multifunctional Design

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Materials

• Lightweight structural materials Non-autoclave Composites

Hybrid Laminates

Tailorable Material Properties

Advanced Propulsion Materials

Hierarchical Structures

Multifunctional Structures*

Structures

• Lightweight conceptsNon-autoclave Primary Structure

Composite Cryogenic Tanks

Carbon Composites / Inflatable Habitats

Expandable Structures

Landers/Habitats*

Adaptive Structures*

* Multifunctional Design

Product Issues for SelectFocus Areas of Materials/Structures

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Materials

• Flexible material systems Expandable Habitat

Flexible EDL Materials

Solar Sail

Shape-Morphing Materials*

Advanced Flexible Materials*

Structures

• Innovative, multifunctional conceptsIntegrated Cryogenic Tank

Integrated Non-pressurized Systems

Reusable Modular Components / Integrated Windows

Active Control of Structural Response

Integrated Pressurized Systems

Structures with Thermal Control*

Integrated Adaptive Structures*

* Multifunctional Design

Product Issues for SelectFocus Areas of Materials/Structures

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NASA TA12 ROADMAP:Assessment – Materials/Structures

• Well laid-out plans for grand challenges, focus areas and product

issues with particular emphasis on multifunctional and lightweight

as critical attributes

• Good balance between mission architecture pull and critical push

technologies addressing mission gaps.

• Insufficient emphasis on close coordination to full integration

between the disciplines of materials and structures for

multifunctional design (which dictates system metrics for

materials functionality).

• Too optimistic about predictive capabilities and VDFL integration.

• Insufficient coverage of weakest link of structures such as joints,

discontinuities, electronic interface, etc from materials viewpoint.

• Imbalanced coverage of evolutionary improvement of reliability

analysis vs “game-changing” technology of autonomic systems

for future deep space missions.

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VISION: EXPANDED

• site specific

• autonomic

AUTONOMIC

AEROSPACE

STRUCTURES

• Sensing & Precognition

• Self-Diagnosis & Actuation

• Self-Healing

• Threat Neutralization

• Self-Cooling

• Self-Powered

Biomimetics

Design for Coupled

Multi-functionality

Nano-materials

Multi-scale

Model

Micro- & Nano-

Devices

Manufacturing Sci

Neural Network &

Information Sci

17

THREE APPROACHES FOR SELF-HEALING

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SEM of 20wt% functionalized capsules in Epoxy (EPON 828/DETA)

10 um

Shell wall

1 μm

100 nm

Microtome Epoxy

(3-glycidoxypropyl)trimethoxysilane

(GLYMO) to limit aggregation and

improve dispersion

SiO2

PUF

Core’09: MICRO & NANOCAPSULESFOR SELF-HEALING (UIUC: Sottos)

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Transitioning of capsule technology for self-healing composites, adhesive & coating

Key challenges are size scale and integration method

Technology Transfer:

SELF-HEALING MATERIALS

– 2006-2009: STTR (AF) on self-healing

aerospace composites

– 2009: STTR (Army) on self-healing, self-

diagnosing multifunctional composites

– Self-healing coatings for electronics

– Application development for adhesive

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Objective:

DoD Benefit:

Technical Approach:

Budget:

$K

Major Reviews/Meetings:

FY05 FY06 FY07 FY08 FY09 FY10

504,311 1,242,709 1,047,076 1,115,244 1,057,424 500,920

To achieve synthetic reproduction of autonomic

functions, such as self-healing and self-cooling,

for aerospace platforms through creation and

integration of complex materials systems

containing microvascular architectures.

(a) Natural models of microvascular systems

are studied to guide the engineering design of

optimal networks for self-healing and self-

cooling structural composites. (b) These

networks are fabricated using “direct-write”

assembly techniques while integrating material

components that realize the desired multi-

functionality. (c) A full compliment of

experimental and analytical techniques are

employed to demonstrate system efficiency.

The advances in self-healing and self-cooling

composite structures will lead to the increase

of reliability and responsiveness of aerospace

vehicles allowing longer flight time and

reduced chance for unexpected failure.

30 August 2006: Seattle, WA

20 August 2007: Urbana, IL

21 August 2008: Arlington, VA

31 August 2009: Urbana, IL

Nature ‘01

MICROVASCULAR COMPOSITES (UIUC/Duke/UCLA: White et al)

MURI ‘05

PM: B. L. Lee (NA); Co-PM: Hugh Delong (NL)

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Microvascular Healing Performance Comparison

• Optimal pressure profiles for “dynamic” pumping enable 100%

healing efficiency for repeated healing cycles

MURI ‘05

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Multiple Network:

2 part epoxy(Toohey et al. Adv. Func. Mat. 2009)

Interpenetrating Network:

2 part epoxy(Hansen et al., Adv. Mat. 2009)

Single Network:

DCPD/Grubbs (Toohey et al, Nature Materials, 2007)

Engineering Design Of Microvascular Network

MURI ‘05

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3D Woven Preform Integration of Sacrificial Fibers Resin Infusion

3D Woven Composite Fiber Removal 3D Vascular Composites

3D Microvacular Composites Via Sacrificial Fibers

MURI ‘05

5 mm

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Journal Covers

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University of BristolMultifunctional Materials Group

Ian BondHollow fiber delivery

EPFL LaussaneLaboratoire de technologie des composites et polymères

Jan-Anders Månson, Véronique MichaudShape memory + self-healing

AFRL/RXPolymers and Composites Branches

Jeff Baur, Rich Vaia, Ajit RoySacrificial wax fibers, permeability testing, composites design

INTERACTIONS WITHOTHER RESEARCH GROUPS

Delft UniversityCentre for Materials

Sybrand van der ZwaagShaped encapsulation vesicles

MURI ‘05

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O

O

O

O

O

Mendomer 401

O

O

O

O

O O

Mendomer 602

Goals:

Less brittle and lower glass transition

temperature (Tg) for better adhesion

and conformal coating

MURI Spin-off >> STTR’08: THERMALLY REMENDABLE COMPOSITES

19

HEAT

THERMALLY REMENDABLEPOLYMERS (UCLA: Wudl)

C O O

O

O

4

N

N

O

O

3

O

+ N

O

O

O

N

O

OPolymer

N N

O

OO

O

MURI ‘05

4th DAMAGE 4th HEALING

5th HEALING5th DAMAGE

Healing of

Delamination

Strain

Energy (mJ)

Healing

Efficiency (Time)

Virgin 10.04

1st healing 8.68 86.4% (1 hr)

2nd healing 8.88 88.4% (2 hr)

3rd healing 9.82 97.8% (3 hr)

4th healing 9.42 93.8% (3 hr)

• Crosslink bonds of Diels-Alder cyclo-addition

polymers are thermally reversible and can be

reestablished after separation (unlike epoxy)

• Fabricated CFRPs with thermally remendable

matrix materials and resistive heating network of

carbon fiber reinforcement

• Demonstrated multiple rounds of healing of

delamination and microcracks

• Resistive heating is dependent on layup

orientation and most uniform with surface

electrodes laid at 45 relative to fibers

• Structural properties of CFRPs are comparable

to traditional epoxy based CFRPs

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VISION: EXPANDED

• site specific

• autonomic

AUTONOMIC

AEROSPACE

STRUCTURES

• Sensing & Precognition

• Self-Diagnosis & Actuation

• Self-Healing

• Threat Neutralization

• Self-Cooling

• Self-Powered

Biomimetics

Design for Coupled

Multi-functionality

Nano-materials

Multi-scale

Model

Micro- & Nano-

Devices

Manufacturing Sci

Neural Network &

Information Sci

28

Thermal Control Via Microvascular Network

cooling

z

h

initial steady state

MURI ‘05

(side view)

Reservoir temperatures

monitored by thermocouples

Fluid temperature in micro-

channels measured by two-

color fluorescent thermometry

technique (also referred to as

laser-induced fluorescence)

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Heat-Transfer

Enhancement >

Increased pressure

drop

Enhancing Heat Transfer with Wavy Microchannels

Serpentine microchannel

Flow direction

2a

Secondary flows due to waviness draw

hot fluid from wall into main flow

streamCrest Trough

•Efficiency of serpentine (wavy) channels in enhancing

convective heat transfer studied computationally to

determine optimal waviness and flow rates.

•Various a/λ studied (a=amplitude;

λ=wavelength of waviness).

•Bulk heat transfer in wavy channels compared

to that of a straight microchannel of equivalent

hydraulic diameter.

Efficiency, η:

MURI ‘05

30

VISION: EXPANDED

• site specific

• autonomic

AUTONOMIC

AEROSPACE

STRUCTURES

• Sensing & Precognition

• Self-Diagnosis & Actuation

• Self-Healing

• Threat Neutralization

• Self-Cooling

• Self-Powered

Biomimetics

Design for Coupled

Multi-functionality

Nano-materials

Multi-scale

Model

Micro- & Nano-

Devices

Manufacturing Sci

Neural Network &

Information Sci

31

Stretchable Matrix

Autonomous System

Multi-Scale Design,

Synthesis & Fabrication

Sensors

(temperature,

pressure,

strain, etc)

Local neurons

(processor, memory,

communication

devices)

BUILT-IN SENSING NETWORK (Stanford/UC/DU/UCLA: Chang et al)

MURI ‘09

Synaptic Circuits

Synapse:

Cognition and decision-making are

determined by a relative level of

cumulative signal strength with respect

to the synapse threshold values

Biological sensory systems

rely on large numbers of

sensors distributed over

large areas and are

specialized to detect and

process a large number of

stimuli. These systems are

also capable to self-organize

and are damage tolerant. PM: B. L. Lee (NA); Co-PM: Hugh Delong (NL)

32

VISION: EXPANDED

• site specific

• autonomic

AUTONOMIC

AEROSPACE

STRUCTURES

• Sensing & Precognition

• Self-Diagnosis & Actuation

• Self-Healing

• Threat Neutralization

• Self-Cooling

• Self-Powered

Biomimetics

Design for Coupled

Multi-functionality

Nano-materials

Multi-scale

Model

Micro- & Nano-

Devices

Manufacturing Sci

Neural Network &

Information Sci

Energy from

Aerospace

Environ

33

Objective:

To develop “self-powered” load-bearing

structures with integrated energy harvest/

storage capabilities, and to establish new multi-

functional design rules for structural

integration of energy conversion means.

DoD Benefit:

Self-powered load-bearing structures with

integrated energy harvest/storage capabilities

will provide meaningful mass savings and

reduced external power requirements over a

wide range of defense platforms including

space vehicles, manned aircraft, unmanned

aerial vehicles, and ISR systems.

Technical Approach:

(a) A combination of experimental and

analytical techniques are employed to advance

the efficiency of the energy conversion means

(as an integral part of load-bearing structures)

and to optimize their multifunctional

performance and ability to cover larger areas.

(b) Multifunctional composites are created with

individual layers acting as photovoltaic/thermo-

electric/piezoelectric power harvesting and

electrochemical power storage elements.

Budget:

$K

FY06 FY07 FY08 FY09 FY10 FY11

693,335 1,169,560 1,180,608 1,219,324 1,179,991 568,571

Major Reviews/Meetings: 29 August 2007: Seattle, WA

5 August 2008: Boulder, CO

11 August 2009: Blacksburg, VA

18 August 2010: Los Angeles, CA

polymer

solar cells

thermo-electrics (TE)antenna system under

the wing with TE

polymer

battery cells

INTEGR’D ENERGY HARVESTING (U WA/U CO/UCLA/VPI: Taya et al)

MURI ‘06

PM: B. L. Lee (NA);

Co-PM’s: Joan Fuller (NA), David Stargel (NA)

34

Optimization of Flight Time of UAV

P

D

L

PLPRBS

BBE

C

SC

WWWW

Et

2/1

2

3

2/32

Flight time (tE) can be increased with structural integration of

energy harvesting and storage capabilities

Thomas and Qidwai, 2004;

Thomas et al, 2006;

Thomas et al, 2008.

BE : the nominal stored battery energy

B : an efficiency factor that accounts for the influence of the current draw rate,

temperature, etc. on the amount of energy that can be extracted from the battery.

SW : the air craft structure weights

BW : the battery weights

PRW : the propulsion weights

PLW : the payload subsystem weights

: air density

S : wing platform area

LC : lift coefficient

DC : drag coefficient

P : the propeller efficiency

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n-type: Mg2Si0.96Bi0.03In0.01 / p-type: Si0.93Ge0.05B0.02

Up-substrate bonding

by using ceramic bond

Down-electrode/substrate Silver paste bonding

on Down-electrode/substrate

TE legs assembly

into plastic moldUp-electrode

bonding

TE module fabrication (6X6 size:18 n-p pairs)

Power generation

0

0.5

1

1.5

2

2.5

3

0 50 100 150 200 250 300

Po

we

r [m

W]

Temperature [C]

Power vs Temperature

MaterialDensity

[g/cm3]

Specific figure of merit

(ZT/Weight)

Average

Clarke

number

(%)At 300K At 800K

Mg2Si 1.95 0.051 /g 0.359 /g 14.83

SiGe* 2.93 n/a 0.171 /g 12.9

Bi2Te3 7.86 0.095 /g 0.038 /g 2.03e-5

CsBi4Te6 7 0.084 /g n/a 2.6e-4

AgPb18SbTe2

08.08 0.05 /g 0.259 /g 6.8e-3

CoSb3-xTex 7.62 0.026 /g 0.098 /g 2.08e-3

Thermoelectric Module FabricationMURI ‘06

36

Developed optical & electrical models of fiber-based OPV cells

Developed coatings & arrays to improve conversion efficiency

Developing deposition methods for more efficient absorbers

Developing encapsulation techniques Collaboration with weavers

Can double efficiency!

Insulating

layer

Active

layer

Insulating

layer

Angle-

Interlock

Construction

Core / PECASE: ENERGY HARVESTING TEXTLES (U Mich: Shtein)