KSC ENGINEER/NG~ANO TECHNOL.OGY

Development of Meandering WindingMagnetometer (MWM®) Eddy Current Sensors for

the Health Monitoring} Modeling and DamageDetection of High Temperature Composite Materials

Rick Russell, NASA KSC

Dr. David Jablonski, Dr. Andy Washabaugh,

Dr. Yanko Sheiretov, Mr. Christopher Martin

and Dr. Neil Goldfine, JENTEK Sensors, Inc.

32nd HIGH TEMPLE Workshop

February 2, 2012

Palm Springs, CA

https://ntrs.nasa.gov/search.jsp?R=20120004241 2018-11-12T12:17:18+00:00Z

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KSC ENGINEERING~ANO TECHNOLOGY

Agenda

• Overview of MWM@ Technology

• Historical application - Space Shuttle RCC

• Recent Developments for COPVs

- Health Monitoring

- NDE

• High Temperature Development

KSC ENGINEERING~ANa TECHNOLOGY

MWM@ Technology

• What is a Meandering Winding Magnetometer (or MWM)?

Primary winding is a linear construct that can be aligned with fibers

Secondary windings for sensing the response

Fabricated on thin flexible substrate creating a conformable sensor

Can be manufactured in various array configurations

Depth of penetration varies with sensor wavelength (spacing) andfrequency

Vendor has capability to perform computer simulations

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Frequency (Hz)

SeconjaryWindings

ES 2 10.2 mm spatial wavelength

.<:a.~ ' 9C 8o 7.~ 6 3.8 mm spatial wavelength

a; 5

a5 •0..

For a nonmagnetic material withelectrical conductivity of 0.02 %IACS ,10

87

•5

.,• -..f .

_MWM® Arrays and Grid MethodsKSC ENGINEERINGAND TECHNOLOGY

MWM FS36

1 :Ir---- 1.00 ---­

1.40-_

11 mm=O.04in.

t U Primary0.25 mm 1 mm

.036 in.

.0875 in.

.050 In.FarChannels

Scan Path Width

MWM-Array

Drive lftftlllltttl!~! Near~Windin JJJl I I nel

, ll~

FA41 A::: 480/190 FA28 A::: 150 mils FS36 A::: 400.0

JE TEKGrid ethods

••

_MWM Sensor SelectionKSC ENGINEERINGAND TECHNOLOGY

• Magnetic field Decays exponentially with distance away from the sensor

• Decay rate determined by skin depth at higher frequencies and sensordimensions at lower frequencies

• Higher frequencies needed to induce significant eddy currents

• Large dimensions needed for thick composites

f..-/4

D~D~

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-w

scanDfrection

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Skin depth: 0 =~v~2

105

10e

107

Frequency (Hz)10·

2

3

• 81__-r--;-'t'1'"'M'1m--;-;-""tTt"t~--r-t--rtT1""t"tt"---;---,r-t"""t"1......----;-r-r-r-t"ttft"""----.--r-r-r-n1t1r7, 3

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WM-Anay I '-'-I' '.i! : :~,

: increacl:ing A I, i,' "

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! ! EIectricaJ Conductivity! "8

i i (kSlm) 100 '\ ~" ,I I I 5

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103

Application: Space Shuttle Orbiter RCC PanelsKSC ENGINEERING~AND TECHNOLOGY

• Foam wheels protect surface• Manual scanning for complex surfaces• C-Scan images of wide areas

built from multiple passes• Adapts automatically to variedcurvatures

Application: Space Shuttle Orbiter RCCKSC ENGINEERING~ PaneIsAND TECHNOLOGY

Blind Test Rec Sample Provided by NASA Langley Research Center

• Scan width = 3- sen ing element = 3. in.• Scans perfOlmed at 1 in.! ec.

Lift-Off Image

Throu2hput: 3.7 in. x 12 in. 'can in 12 econds = 3.7 sq. in. "ec

....KSC ENGINEERINGANO TECHNOLOGY

COPV Testing - Effect of FiberOrientation

0_08"AI Liner

12 .. 10'

11

11

'-0

, aDe 09

08 0.9

15.84 MHz - Magnitude va. X axis

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a.

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02 0.30100

0623

062'

0627

oem

0629

0622

0"'"

-30

-25

-20

• Multiple fiber orientations in several different layers

• Orientation measurements with FS33

- 15.8 MHz data indicated

• Limited penetration depth of MWM so outermost hoop (900) layer barely visible

~KSC ENGINEERINGAND TECHNOLOGY

COPV - Health MonitoringProof of Concept Coupon Testing

Stresses produced by compressive loading oftapered wedges

• Coupon cut from center section ofCOPV (""4// wide)

• Two test fixtures designed

• Due to cutting only hoop directioncould be measured

• Several different sensor designs andorientations were tested

Stresses produced by tensileloading of specially design test

fixture

1.0025

1.0020

1.0015

:0-1.0010Q)

J:!IVE 1.0005~

~ 1.0000Q)

-g.-t:::: 0.9995CC)IV:;: 0.9990

0.9985

0.99800 20 40 60 80 100 120 140 160 180 200

Set Number

Example of results from compressiveloading of tapered wedges test 9

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KSC ENGINEERING ......AND TECHNDLOGY

COPV - Health MonitoringProof of Concept Hydrostatic Test

• Full COPV tested hydrostatically at KSC on February 5, 2011

• Vessel cycled to 8,000 psi and back to zero stopping at 2,000 psi increments

- Pressure chosen to mimic MEOP

- Estimated design burst pressure of COPV is 16,000 psi

• Based on coupon tests 3 sensor configurations were chosen

- Different wavelength to obtain various depth of penetration

• Tests were performed with 3 sensor orientations

- 90Q, 60Q and 17Q to align sensor drive with fiber orientations

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COPV - Health Monitoring~,eg~~gk'XF&~~~~roof of Concept Hydrostatic Test

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Pressurization IntervalAxial strain

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20

-.....-------,

o uPressurization Interval

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I17·SensorOrientalion60· SensorOrientalion90· Sensor Orientationo."'~

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Hoop strain

• <......

KSC ENGINEERING~AND TECHNOLOGY

COPV NDE

• Four COPVs selected from NASA White Sandsinventory

• Scanned via MWM before and after impact testing

KSC ENGINEEA/NG ....AND TECHNOLOGY

Rotation Scans

FA28 W ..Array Scan

" :7, , ~

•

Jest setup for hoop oriented fibersKSC ENGINEERING.allUn Ttt:r-WllUn, ,..,,..,v

.-~

~KSC ENGINEERINGAND TECHNOLOGY

Lift-Off Image Low Frequency

Before Impact Damage

axial • •

After Impact Damage Baseline Subtracted Preliminary Filtering

• Sample AC5250-030; 90 0 Sensor drive orientation• Higher impact energy results in larger dents in the aluminum liner• Sensor: MWM-Array FA24• 50.11 kHz

• y .."

KSC ENGINEERING~AND TECHNOLOGY

Lift-Off Image High Frequency

Before Impact Damage

axial • ~

After Impact Damage

........-------~.

Baseline Subtracted Preliminary Filtering

• Sampte AC5250-030; 900 Sensor drive orientation• Sensor: MWM-Array FA24• 5.011 MHz

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KSC ENGINEERING~ANO TECHNOL.OGY

Scan of COPV with Insulation Blanket

Lift-off C-scan for COPY AC5251-005 without an MLilayer (50 kHz)

Test Setup

Lift-off C-scan for COpy AC5251-005 with a conductiveMLI layer placed over the COPY (50 kHz)

"

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KSC ENGINEERING ......AND TECHNOLOGY

Composite Structure Impact Damage

Detection

Composite Specimen withImpact Damage on Scanning Bed

Specimen provided by Lockheed Martin 15.84MHz image taken withscanning MWM-Array for

effective conductjvity

Proximity

MWM-Array imageof proximity to first

fiber layer

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KSC ENGINEEA/NG~AND TECHNOLOGY

Composite Property Variation withStress

PerpendicularParallel-45

•Bending Strain Direction

FA28 orientation tosurface fibers: +45

FA28. onentation to surface fibers:- .... - parallel (with 8 mR shim)-+- perpendicular (with 8 mil shim)..•. -45

-. 45

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OAO0.350.20 0.25 0.30

Strain %0.15010

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0.05

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High TemperatureMWM-Array Sensor

Room TemperatureMWM-Array Sensor

Development of a High Temperature~f!&g f.'lgkl\ffcfll!l~l~ -- M W MArray 5ens0 r

• Designed for continuous use at1000° C by proper selection ofhigh temperature materials.

• Ceramic substrate and high­temperature metal depositedconductive winding constructs.

• Prototype 7-channel MWM-Arraysensor built and tested at 850° Cwith no degradation observed.

• Demonstrated crack detectionwith prototype high temperaturesensor.

• High temperature cabling issuesrequire further development