High-Temperature Strain Sensing for Aerospace Applications · PDF file ·...

25
Cleared for public release High High - - Temperature Strain Sensing Temperature Strain Sensing for Aerospace Applications for Aerospace Applications Anthony (Nino) Piazza, Dr. Lance W. Richards, Larry D. Hudson NASA Dryden Flight Research Center Summer WRSGC in Bethlehem, PA August 18-20, 2008

Transcript of High-Temperature Strain Sensing for Aerospace Applications · PDF file ·...

Page 1: High-Temperature Strain Sensing for Aerospace Applications · PDF file · 2013-04-10High-Temperature Strain Sensing for Aerospace Applications Anthony (Nino) Piazza, ... (unbonded)

Cleared for public release

HighHigh--Temperature Strain Sensing Temperature Strain Sensing for Aerospace Applicationsfor Aerospace Applications

Anthony (Nino) Piazza, Dr. Lance W. Richards, Larry D. HudsonNASA Dryden Flight Research CenterSummer WRSGC in Bethlehem, PA

August 18-20, 2008

https://ntrs.nasa.gov/search.jsp?R=20080037427 2018-05-13T20:39:18+00:00Z

Page 2: High-Temperature Strain Sensing for Aerospace Applications · PDF file · 2013-04-10High-Temperature Strain Sensing for Aerospace Applications Anthony (Nino) Piazza, ... (unbonded)

Dryden Flight Research Center

Background•

Objective

Sensors•

Attachment Techniques

Laboratory Evaluation / Characterization

Large-Scale Structures

Outline

Page 3: High-Temperature Strain Sensing for Aerospace Applications · PDF file · 2013-04-10High-Temperature Strain Sensing for Aerospace Applications Anthony (Nino) Piazza, ... (unbonded)

Dryden Flight Research Center

LowMediumHigh

LowMediumHigh

FoilStrain Gage

WeldableStrain Gage

Wire WoundStrain Gage

Silica Fiber Optic Strain Gage

2000

Sapphire Fiber Optic Strain Gage

30001000

Difficulty of InstallationHot Structures

Strain MeasurementArea of Need

Com

mer

cial

ly A

vaila

ble

Strain Sensor Type

Difficulty of Use

LowMediumHigh

LowMediumHigh

FoilStrain Gage

WeldableStrain Gage

Wire WoundStrain Gage

Silica Fiber Optic Strain Gage

2000

Sapphire Fiber Optic Strain Gage

30001000

Difficulty of InstallationHot Structures

Strain MeasurementArea of Need

Com

mer

cial

ly A

vaila

ble

Strain Sensor Type

Difficulty of Use

Lack of Capability•

TPS and hot structures are utilizing advanced materials that operate at temperatures that exceed our ability to measure structural performance

Robust strain sensors that operate accurately and reliably beyond 1800°F are needed but do not exist

Implication•

Hinders ability to validate analysis and modeling techniques•

Hinders ability to optimization structural designs

Background Sensor Development Motivation

Page 4: High-Temperature Strain Sensing for Aerospace Applications · PDF file · 2013-04-10High-Temperature Strain Sensing for Aerospace Applications Anthony (Nino) Piazza, ... (unbonded)

Dryden Flight Research Center

Provide strain data for validating finite element models and thermal-structural analyses

Develop sensor attachment techniques for relevant structural materials at the small test specimen level

Apply methods to large scale hot-structures test articles•

Perform laboratory tests to characterize sensor and generate corrections to apply to indicated strains

Objective Measurements Lab

Page 5: High-Temperature Strain Sensing for Aerospace Applications · PDF file · 2013-04-10High-Temperature Strain Sensing for Aerospace Applications Anthony (Nino) Piazza, ... (unbonded)

Dryden Flight Research Center

High-Temp Quarter-Bridge Strain Gage

Pro’s•

Sturdy / rugged thermal sprayed installation and spot-welded leadwire stakedown

Available high sample rate DAS, usually AC coupled to negate large ξapp

Con’s•

Large magnitude ξapp

primarily due to wire TCR, slope rotates cycle-to-cycle

Sensitivity (GF): Function of temperature

Apparent Strain = [TCRgage / GFset + (αsub - αgage)] * (ΔT)

R1

R3 R2

R4

+ EX

- S + S

- EX

Red

Black

WhiteGreen

Wheatstone Bridge

(Δ R / R) * GF = RTξ

Sensors Dynamic Measurements (Max Op 1850°F)

-15000

-12000

-9000

-6000

-3000

0

0 500 1000 1500Temp (F)

Str

ain

()

1st Cycle2nd Cycle3rd Cycle

-14000

-13000

-12000

-11000

-10000

800 1000 1200 1400 1600

1st Cycle2nd Cycle3rd Cycle

PTZ

RotationDirection

Heat / Cool Rate:1 °F / sec

-15000

-12000

-9000

-6000

-3000

0

0 500 1000 1500Temp (F)

Str

ain

()

1st Cycle2nd Cycle3rd Cycle

-14000

-13000

-12000

-11000

-10000

800 1000 1200 1400 1600

1st Cycle2nd Cycle3rd Cycle

PTZ

RotationDirection

Heat / Cool Rate:1 °F / sec

Page 6: High-Temperature Strain Sensing for Aerospace Applications · PDF file · 2013-04-10High-Temperature Strain Sensing for Aerospace Applications Anthony (Nino) Piazza, ... (unbonded)

Dryden Flight Research Center

Strain / LG (initial), where sensitivity = LG

Apparent Strain (ξapp) = (αsub - αfiber) * ΔT

LC

CeramicAttach

LG

Extrinsic Fabry-Perot Interferometer (EFPI)Commercially Available

Sensors Static Measurement (Max Op 1850°F)

SM gold coated fiber 125μm dia, 6μm core 840nm tuned

Silica micro-capillary:OD = 285μm ID = 130μm

840nm, 50μW

Strain = δLC

Page 7: High-Temperature Strain Sensing for Aerospace Applications · PDF file · 2013-04-10High-Temperature Strain Sensing for Aerospace Applications Anthony (Nino) Piazza, ... (unbonded)

Dryden Flight Research Center

BB OpticalSource

PowerSplitter

DiffractionGratingMini

Spectrometer

Lens

CCDOut to Signal

Processor

Single Mode EFPI Signal Conditioning

Sensors Static Measurement

Page 8: High-Temperature Strain Sensing for Aerospace Applications · PDF file · 2013-04-10High-Temperature Strain Sensing for Aerospace Applications Anthony (Nino) Piazza, ... (unbonded)

Dryden Flight Research Center

Sensors Static Measurement (Max Op 600°F)

Reflected λ

Reflected λTensile Load

ε

λ

ε

λ

BBR

E

Freq / Dist

DiodeTunable

Laser

FFTE

λ

IFFTStrain (με)(δλ / λ) x 0.725

Unstrained

SM Polyimide Coated Fiber125μm dia, 9μm core, 1550nm

2 x 1Coupler

Page 9: High-Temperature Strain Sensing for Aerospace Applications · PDF file · 2013-04-10High-Temperature Strain Sensing for Aerospace Applications Anthony (Nino) Piazza, ... (unbonded)

Dryden Flight Research Center

Develop sensor attachment techniques for relevant structural materials

Derive surface prep and optimal plasma spray parameters for applicable substrate

i.e., powder media / type, power level, traverse rate, feed rate, and spraying distance

Or, optimize / select cement that best fits application•

Improve methods of handling and protecting fragile sensor during harsh installation processes

Attachment Techniques Applications Above 600°F

Page 10: High-Temperature Strain Sensing for Aerospace Applications · PDF file · 2013-04-10High-Temperature Strain Sensing for Aerospace Applications Anthony (Nino) Piazza, ... (unbonded)

Dryden Flight Research Center

Attachment Techniques Thermal Spray vs. Cement

Thermal sprayed attachments are preferred even though cements are simpler to apply

Cements are often corrosive to TC or strain gage alloys–

Si / Pt, NaF

/ Fe-Cr-Al alloys, alkali silicate / Cr

Tests indicate increased EFPI gage-to-gage scatter on first cycle

Positive lead ofK-Type TC (NiCr)

Post-Test: One cycle to 2550°F

Cements are more prone to bond failure due to shrinkage and cracking caused when binders dissipate

Page 11: High-Temperature Strain Sensing for Aerospace Applications · PDF file · 2013-04-10High-Temperature Strain Sensing for Aerospace Applications Anthony (Nino) Piazza, ... (unbonded)

Dryden Flight Research Center

Thermal Spray Room•

80KW Plasma System•

Rokide Flame-Spray System•

Powder Spray System•

Grit-Blast Cabinet•

Micro-Blast System•

Water Curtain Spray Booth

Attachment Techniques Thermal Spray Equipment

Page 12: High-Temperature Strain Sensing for Aerospace Applications · PDF file · 2013-04-10High-Temperature Strain Sensing for Aerospace Applications Anthony (Nino) Piazza, ... (unbonded)

Dryden Flight Research Center

Arc-plasma sprayed base coat•

Metallic Substrates: Used to transition high expansion substrate

metal with low expansion sensor attachment material (Al2

O3

)•

CMC Substrates (inert testing): High melting-point ductile transitional metals (i.e. Ta, TiO2

, & Mo) more conducive for attachment to smooth surfaces like SiC

Rokide flame-sprayed sensor attachment•

Applies a less dense form of alumina

than plasma spraying•

Electrically insulates (encapsulate) wire resistive strain gages

Collaborative work has been done through grants with Dr. Richard Knight, Drexel University

Attachment Techniques Thermal Spray

Page 13: High-Temperature Strain Sensing for Aerospace Applications · PDF file · 2013-04-10High-Temperature Strain Sensing for Aerospace Applications Anthony (Nino) Piazza, ... (unbonded)

Dryden Flight Research Center

Attachment Techniques Wire Strain Gage Installation

Place SG on thermal sprayed basecoats via carrier tape

Apply flame-sprayed tack and cover coats

Spot weld three- conductor leadwire

Page 14: High-Temperature Strain Sensing for Aerospace Applications · PDF file · 2013-04-10High-Temperature Strain Sensing for Aerospace Applications Anthony (Nino) Piazza, ... (unbonded)

Dryden Flight Research Center

8.5mm

0.35”

Attachment Techniques Fiber Optic EFPI Installation

Flame-spray sensor attachment

Transfer to thermal sprayed base coat using carrier tape

Fabricate sensor under microscope

Page 15: High-Temperature Strain Sensing for Aerospace Applications · PDF file · 2013-04-10High-Temperature Strain Sensing for Aerospace Applications Anthony (Nino) Piazza, ... (unbonded)

Dryden Flight Research Center

Attachment Techniques Fiber Optic EFPI Installation

1. Plasma Spray Basecoat (2-mil)

2. Rokide Flame- Spray Intermediate Layer (1-mil)

3. Set EFPI Sensor in Place Using Carrier Tape

4. Rokide Flame-Spray Attachment Layer (minimal coverage)

Page 16: High-Temperature Strain Sensing for Aerospace Applications · PDF file · 2013-04-10High-Temperature Strain Sensing for Aerospace Applications Anthony (Nino) Piazza, ... (unbonded)

Dryden Flight Research Center

Refrasil Overbraid

Two applications of MB610 sufficiently coat fiber (Cured @ 270°F)

Bonded FBG’s Type-K TC

Polyimide coated EFPI bonded with mixture of

GA-61 and MB610

Attachment Techniques Applications Below 600°F

4-in

Page 17: High-Temperature Strain Sensing for Aerospace Applications · PDF file · 2013-04-10High-Temperature Strain Sensing for Aerospace Applications Anthony (Nino) Piazza, ... (unbonded)

Dryden Flight Research Center

Validate and characterize strain measurement•

Base-line / characterize high-temperature strain sensors on monolithic Inconel specimens

Known material spec’s isolate substrate from inherent sensor traits prior to testing on more complex composites

Evaluate / characterize sensitivity (GF) of strain sensors on ceramic composite substrates using laboratory combined thermal / mechanical load fixture

Generate apparent strain curves for corrections of indicated strains on relevant ceramic composite hot-structures

Evaluation / Characterization

Page 18: High-Temperature Strain Sensing for Aerospace Applications · PDF file · 2013-04-10High-Temperature Strain Sensing for Aerospace Applications Anthony (Nino) Piazza, ... (unbonded)

Dryden Flight Research Center

Clamping Beam

Loading MandrelsSide ALoading

Side BLoading

13 in.

Clamping Beam

Loading MandrelsSide ALoading

Side BLoading

13 in.

Clamping Beam

Loading MandrelsSide ALoading

Side BLoading

13 in.

Evaluation / Characterization Combined Thermal / Mechanical Loading (Obsolete)

Thermal / Mechanical Cantilever Beam Testing of EFPI’s•

Excellent correlation with SG to 550°F (3%)•

Very little change to 1200°F•

Slight drop in output slope above 1200°F•

Maximum gap readability uncertain at upper range temperatures on high expansion material

-1200

-600

0

600

1200

-0.200 -0.100 0.000 0.100 0.200

Deflection (in.)

Stra

in (u

e)

Ave SG

L02

L02 (KSo)

Tension

Compression

Standoff Correction FactorKSo = c/(c+So) = 0.189 / 0.189 + 0.0055 = 0.972 where: c = Distance from Neutral axis So = Distance from centerline of fiber (in tube) to substrate

FS2000 SettingsExtended Range: ONGap Limit: OFFSample Interval: 100msAnalog Out: On (1:0.1)

EFPI Combined Loading on IN625

Loading Mandrels

LVDT’sExtensions

ClampingBeam

LoadBar

TOP VIEW

1800°F, Air Only

Page 19: High-Temperature Strain Sensing for Aerospace Applications · PDF file · 2013-04-10High-Temperature Strain Sensing for Aerospace Applications Anthony (Nino) Piazza, ... (unbonded)

Dryden Flight Research Center

Furnace / cantilever beam loading system for sensitivity testing

Air or inert (3000°F max)•

12-in3

inner furnace with Molydisilicide

elements

Micrometer / mandrel side loading•

LVDT displacement measurements•

POCO Graphite hardware for inert environment testing of ceramic composites

IN625 hardware for metallic testing in air•

Sapphire viewing windows

LoadingMandrel

LVDT

Clamping Beam

Constant Strain Load Bar

Evaluation / Characterization Combined Thermal / Mechanical Loading (Current)

Page 20: High-Temperature Strain Sensing for Aerospace Applications · PDF file · 2013-04-10High-Temperature Strain Sensing for Aerospace Applications Anthony (Nino) Piazza, ... (unbonded)

Dryden Flight Research Center

Sensor Characterization Air or inert (3000°F max)

Evaluate bond integrity•

Generate ξapp correction curves•

Evaluate sensitivity and accuracy•

Evaluate sensor-to-sensor scatter, repeatability, hysteresis, and drift

Modified Dilatometer System

4 EFPI’s on C-C

Evaluation / Characterization Dilatometer Testing

Page 21: High-Temperature Strain Sensing for Aerospace Applications · PDF file · 2013-04-10High-Temperature Strain Sensing for Aerospace Applications Anthony (Nino) Piazza, ... (unbonded)

Dryden Flight Research Center

ξapp Correction: Removal of inherent sensor traits and substrate expansion from indicated strain to acquire true strains or thermal stresses

ξtrue = ξindicated – ξapp, where ξapp = (αsub - αfiber) * ΔT•

Inconel (LH chart): Large expansion differential between IN601 and Si –

output primarily substrate expansion, CTE * ΔT

CMC (RH chart): Small expansion ratio between C-SiC and Si–

requires correction for fiber expansion (lessening cavity gap)

Graphs demonstrate how well actual ξapp curves followed theoretical

0

4000

8000

12000

16000

0 400 800 1200 1600

Temp (F)

Stra

in (u

e)

-500

-250

0

250

500

Dev

iatio

n fr

om C

oupo

n Ex

pans

ion

Coupon (dL/L)EFPI 3EFPI 4Dev EFPI 3Dev EFPI 4

Heating rate: 7.2 °F/minCoupon Substrate: IN601

File: LC2a900C1

Inconel Substrate

y = 1E-10x4 - 2E-07x3 + 0.0006x2 + 0.3096x - 30.1290

500

1000

1500

2000

2500

0 600 1200 1800

Temp (F)

Stra

in ( μ

ε)

Coupon DL/L

Average all FO

Theoretical Eapp

CMC Substrate

Evaluation / Characterization EFPI Apparent Strain

Page 22: High-Temperature Strain Sensing for Aerospace Applications · PDF file · 2013-04-10High-Temperature Strain Sensing for Aerospace Applications Anthony (Nino) Piazza, ... (unbonded)

Dryden Flight Research Center

Evaluation / Characterization FBG Apparent Strain

y = 0.0044x2 + 3.6664x - 302.93

0

500

1000

1500

2000

2500

0 100 200 300 400 500

Temp (F)

Stra

in ( μ

ε)

Theoretical Thermal Out

Average Eapp (12)

Poly. (Average Eapp (12))Thermal Out (unbonded) = (α fiber + ξ / Pe) * ΔT

where:Thermal Optic Effect (ξ) = 3.78 με/FStrain Optic Constant (Pe) = 0.725

FBG on Graphite/Epoxy Composite0

500

1000

1500

2000

2500

9:21:36 9:28:48 9:36:00 9:43:12 9:50:24 9:57:36 10:04:48

Time

Stra

in ( μ

ε)

Bonded to substrate

Not bonded to substrate

Heating/Cooling Rate: 0.5F/sec

Page 23: High-Temperature Strain Sensing for Aerospace Applications · PDF file · 2013-04-10High-Temperature Strain Sensing for Aerospace Applications Anthony (Nino) Piazza, ... (unbonded)

Dryden Flight Research Center

Large Scale Structures Ceramic Composite Control Surfaces

C/C Control SurfaceMarch, 2003C/C Control SurfaceMarch, 2003

C/SiC BodyflapNov, 2003

C/SiC BodyflapNov, 2003

X-37 C/C FlaperonSubcomponent

August, 2004

X-37 C/C FlaperonSubcomponent

August, 2004

X-37 C/SiC FlaperonSubcomponentMay, 2004

X-37 C/SiC FlaperonSubcomponentMay, 2004

2000°F2000°F

2400°F2400°F 2300°F2300°F

2100°F2100°F

X-37 C/C Flaperon Qual UnitAugust, 2005

X-37 C/C Flaperon Qual UnitAugust, 2005

2500°F2500°FC/C Control SurfaceMarch, 2003C/C Control SurfaceMarch, 2003

C/SiC BodyflapNov, 2003

C/SiC BodyflapNov, 2003

X-37 C/C FlaperonSubcomponent

August, 2004

X-37 C/C FlaperonSubcomponent

August, 2004

X-37 C/SiC FlaperonSubcomponentMay, 2004

X-37 C/SiC FlaperonSubcomponentMay, 2004

2000°F2000°F

2400°F2400°F 2300°F2300°F

2100°F2100°F

X-37 C/C Flaperon Qual UnitAugust, 2005

X-37 C/C Flaperon Qual UnitAugust, 2005

2500°F2500°F

Page 24: High-Temperature Strain Sensing for Aerospace Applications · PDF file · 2013-04-10High-Temperature Strain Sensing for Aerospace Applications Anthony (Nino) Piazza, ... (unbonded)

Dryden Flight Research Center

Large Scale Structures Metallic Dynamic Environment

C-17 Engine Testing•

Test temperatures above 1100°F•

Engine intentionally unbalanced creating large peak-to-peak vibrations

X-33 Sonic Fatigue Testing•

Dynamic loads as high as -158db•

Test temperatures above 1500°F•

High transient heating rates producing large thermal stresses

Page 25: High-Temperature Strain Sensing for Aerospace Applications · PDF file · 2013-04-10High-Temperature Strain Sensing for Aerospace Applications Anthony (Nino) Piazza, ... (unbonded)

Dryden Flight Research Center

Large Scale Structures Fiber Optic Wing Shape Sensing

NASA Dryden Predator B (Ikhana)

ξapp coupon tested from -60°F to 150°F