identification of aging aircraft electrical wiring woolrich engineering consulting firm group...
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Identification of Aging Aircraft Identification of Aging Aircraft Electrical WiringElectrical Wiring
Woolrich Engineering Consulting FirmWoolrich Engineering Consulting Firm
Group Members:
Robert Beremand
Chad Hanak
Melissa Straubel
Sponsors:
Dr. R.O. Stearman
Marcus Kruger
(“Identification of Aging Aircraft Electrical Wiring,” December 2002)
OverviewOverview
History of the ProblemHistory of the Problem
TheoryTheory
Project ObjectivesProject Objectives
Experimental SetupExperimental Setup
Lab AgingLab Aging
Age AnalysisAge Analysis
RecommendationsRecommendations
History of the ProblemHistory of the Problem
SolutionsSolutions– Visual inspectionVisual inspection
Impractical Impractical
– Triboelectric responseTriboelectric responseMay indicate condition of May indicate condition of wirewire
(“Identification of Aging Aircraft Electrical Wiring,” December 2002)
Faulty electrical wiringFaulty electrical wiring– Chafing and cracking insulationChafing and cracking insulation– Electrical firesElectrical fires– ArcingArcing
History
Theory
Objectives
Experimental Setup
Aging
Age Analysis
Recommendations
Triboelectric EffectTriboelectric Effect
Static ElectricityStatic Electricity– 2 materials slide 2 materials slide
against each otheragainst each other
Frictional force Frictional force causes charge causes charge imbalanceimbalance
History
Theory
Objectives
Experimental Setup
Aging
Age Analysis
Recommendations
(“Identification of Aging Aircraft Electrical Wiring,” December 2002)
Induced currentInduced current– Unwanted noise and Unwanted noise and
interferenceinterference
Magnitude dependent Magnitude dependent on numerous factorson numerous factors
Project ObjectivesProject Objectives
Laboratory AgingLaboratory Aging– Simulate aging through:Simulate aging through:
Temperature & humidityTemperature & humidity– Hot and coldHot and cold
Jet-A fuelJet-A fuel
Saltwater solutionSaltwater solution
Temperature cyclingTemperature cycling
Combination of allCombination of all– Visual/Touch inspectionVisual/Touch inspection
– Did not completeDid not complete
History
Theory
Objectives
Experimental Setup
Aging
Age Analysis
Recommendations
Project ObjectivesProject Objectives
Age AnalysisAge Analysis– Does age influence Does age influence
triboelectric effect?triboelectric effect?– Determine signal Determine signal
response to inputsresponse to inputs– Relate age to Relate age to
measured triboelectric measured triboelectric responseresponse
– Vibration Vibration Wire Wire CurrentCurrent
– More successfulMore successful
History
Theory
Objectives
Experimental Setup
Aging
Age Analysis
Recommendations
Alpha Wire SpecimenAlpha Wire Specimen
KaptonKapton– Too expensiveToo expensive– Hard to obtainHard to obtain
Alpha Wire 1632Alpha Wire 1632– 20 Gauge (thick)20 Gauge (thick)– Stranded, Tinned CopperStranded, Tinned Copper– Rubber InsulationRubber Insulation– Low temperature Low temperature
tolerancetolerance-30-30
oo to 90 to 90
oo C C
– Majority of testing was Majority of testing was conducted on this type of conducted on this type of wirewire
oooo
(Alpha 1632)
History
Theory
Objectives
Experimental Setup
Aging
Age Analysis
Recommendations
Test SetupTest Setup
HP Signal Analyzer software & DAS – means of HP Signal Analyzer software & DAS – means of interpreting signal and its responseinterpreting signal and its response– Wanted to use IDEAS, bug in softwareWanted to use IDEAS, bug in software
Fixed sinusoidal vibration – determine triboelectric Fixed sinusoidal vibration – determine triboelectric response at fixed frequency of wires of different agesresponse at fixed frequency of wires of different ages
History
Theory
Objectives
Experimental Setup
Aging
Age Analysis
Recommendations
Signal Analyzer
DAS Amplifier Shaker
Wire Circuit
Stinger
Chessboard
Test SetupTest Setup
Stinger – transmit vibration from shaker to Stinger – transmit vibration from shaker to platformplatform
Chessboard – platform on which wire circuit was Chessboard – platform on which wire circuit was mountedmounted
Signal Analyzer
DAS Amplifier Shaker
Wire Circuit
Stinger
Chessboard
History
Theory
Objectives
Experimental Setup
Aging
Age Analysis
Recommendations
Test Setup – Vertical vs. HorizontalTest Setup – Vertical vs. Horizontal
VerticalVertical– First used checkerboard-First used checkerboard-
previous groupprevious group– Structure is straightStructure is straight
No loop antennaNo loop antenna– More wire in contact with More wire in contact with
shaker surface (gravity)shaker surface (gravity)
HorizontalHorizontal– Grounded metal Grounded metal
encasement to provide encasement to provide shielding from EMIshielding from EMI
– StrutStrut– Longer stinger possibleLonger stinger possible
More distance More distance between shaker and between shaker and platformplatform
– One dimensional motionOne dimensional motion
History
Theory
Objectives
Experimental Setup
Aging
Age Analysis
Recommendations
(Horizontal test setup)
Wire Tension and TwistingWire Tension and Twisting
New wire – tendency to untwistNew wire – tendency to untwist– Varied tensionVaried tension
Did not notice real benefit to twisting new Did not notice real benefit to twisting new wirewireConsistent tension neededConsistent tension needed– Response varied with tension – can’t see trendsResponse varied with tension – can’t see trends– Mean decreased as tension increasedMean decreased as tension increased– Standard deviation decreased even moreStandard deviation decreased even more
Difficult to achieve uniform tension from Difficult to achieve uniform tension from wire to wirewire to wire– Consequently, most test were conducted with Consequently, most test were conducted with
the wire under no tensionthe wire under no tension– Could change with better test setupCould change with better test setup
History
Theory
Objectives
Experimental Setup
Aging
Age Analysis
Recommendations
Wire OrientationWire OrientationImprove Improve consistencyconsistencyOrientation of wire Orientation of wire on checkerboard on checkerboard appeared to affect appeared to affect amplitude of amplitude of triboelectric triboelectric responseresponseAffixed plastic Affixed plastic hooks to board to hooks to board to insure uniform insure uniform orientation of wire orientation of wire from test to testfrom test to test
History
Theory
Objectives
Experimental Setup
Aging
Age Analysis
Recommendations
(Wire orientation)
Examination of TwistingExamination of Twisting
Dispute over effect of twisting on Dispute over effect of twisting on EMI and Triboelectric EffectEMI and Triboelectric Effect– Connections and Current FlowConnections and Current Flow
Parallel and SeriesParallel and Series
History
Theory
Objectives
Experimental Setup
Aging
Age Analysis
Recommendations
Laboratory AgingLaboratory AgingTemperature and HumidityTemperature and Humidity– Previous success with heat alonePrevious success with heat alone
Go hotterGo hotter– Add Cold TestAdd Cold Test– Temperature Cycles, Temperature ExtremesTemperature Cycles, Temperature Extremes– Limited previous results from humidity aloneLimited previous results from humidity alone
Combine temperature and humidity exposureCombine temperature and humidity exposureFreezing and ThawingFreezing and Thawing
– Tension test ?Tension test ?CorrosivesCorrosives– Jet-A fuel SoakJet-A fuel Soak
Visually obvious effects in previous work, swellingVisually obvious effects in previous work, swelling– Saltwater SoakSaltwater Soak– Residue Effects?Residue Effects?
Graphite lubricantGraphite lubricant
Combination CycleCombination Cycle
History
Theory
Objectives
Experimental Setup
Aging
Age Analysis
Recommendations
Aging: 10x The DataAging: 10x The Data
Remove 1 Sample
at a Time
Test Sampleand Do Not
Return it
Aging Process Remove
all 10Samples
Return Samplesto AgingProcess
AgingProcess
TestSamples
Previous Cycle
New Cycle
History
Theory
Objectives
Experimental Setup
Aging
Age Analysis
Recommendations
Aging EquipmentAging EquipmentKitchen OvensKitchen Ovens– Can’t run continuouslyCan’t run continuously
Drying OvensDrying Ovens– Remove humidityRemove humidity
IncubatorsIncubators– Most don’t get hot enoughMost don’t get hot enough
Environmental ChambersEnvironmental Chambers– Large temperature rangeLarge temperature range– Humidity ControlHumidity Control– ProgrammableProgrammable– Too expensiveToo expensive
(A Bluem Environmental Chamber)(Courtesy of www.lunaire.com)
History
Theory
Objectives
Experimental Setup
Aging
Age Analysis
Recommendations
Aging EquipmentAging EquipmentZoology to the rescue?Zoology to the rescue?
– Old IncubatorOld IncubatorHumidity controlHumidity control
Adequate heat ?Adequate heat ?
Working conditionWorking condition
FREE (eventually?)FREE (eventually?)
– Old FreezerOld FreezerNo humidity controlNo humidity control
Needs cleaningNeeds cleaning
FREE (eventually?)FREE (eventually?)
(The Freezer)
(The Zoology Building)(Courtesy of www.utexas.edu)
History
Theory
Objectives
Experimental Setup
Aging
Age Analysis
Recommendations
Anticipated ResultsAnticipated ResultsMaterial characteristics should change Material characteristics should change – Texture Texture – Coefficient of FrictionCoefficient of Friction– Capacitance Capacitance – ResistanceResistance
Changes should be reflected in the Changes should be reflected in the triboelectric response, and are expected to triboelectric response, and are expected to follow a detectable pattern.follow a detectable pattern.
History
Theory
Objectives
Experimental Setup
Aging
Age Analysis
Recommendations
Age AnalysisAge Analysis
Dispersed test setup components over Dispersed test setup components over large area to reduce Electro-Magnetic large area to reduce Electro-Magnetic Interference (EMI)Interference (EMI)Attempted to verify repeatability with test Attempted to verify repeatability with test setupsetupTested various sets of artificially aged Tested various sets of artificially aged wires to look for age-dependent trends in wires to look for age-dependent trends in their triboelectric responsestheir triboelectric responsesSeparately enclosed shaker and test Separately enclosed shaker and test platform in grounded foil to further reduce platform in grounded foil to further reduce EMIEMIArrived at some conclusions about test Arrived at some conclusions about test setupsetup
History
Theory
Objectives
Experimental Setup
Aging
Age Analysis
Recommendations
Anticipated ResultsAnticipated Results
dx
Shaker
Wire
V
•E = portion of energy output by shaker that is transmitted to wire through friction
•E = f(σhoop)(2πrL)µk|dx|
•V = V(dE/dt, M1, M2)
where M1, M2 are material properties
•We expect to find an empirical formula that describes how V changes with age
L
R
Shaker/Wire Test Setup:
History
Theory
Objectives
Experimental Setup
Aging
Age Analysis
Recommendations
Statistical OverviewStatistical Overview
Fall 2002 group concluded triboelectric Fall 2002 group concluded triboelectric response amplitudes were random.response amplitudes were random.
WireWire Response to 1KHz, 100mV sinusoid input Response to 1KHz, 100mV sinusoid input (mV)(mV)
Nominal 1Nominal 1 2.1162.116 0.1420.142 0.6770.677 0.1310.131 1.9281.928
Nominal 2Nominal 2 0.7380.738 0.1450.145 2.3552.355 0.2220.222 0.4320.432
Humidity 1Humidity 1
(3.5 days)(3.5 days)
1.9701.970
Humidity 5Humidity 5
(17.5 days)(17.5 days)
2.0632.063
Humidity 10Humidity 10
(35 days)(35 days)
1.7201.720
History
Theory
Objectives
Experimental Setup
Aging
Age Analysis
Recommendations
Statistical OverviewStatistical Overview
Hypothesis: points are not random, but Hypothesis: points are not random, but centered about a fixed mean with a centered about a fixed mean with a large variance (large variance (σσ22))Attempted to experimentally determine Attempted to experimentally determine mean and mean and σσ22 values to see if trends values to see if trends existedexistedEach wire specimen was tested 15 Each wire specimen was tested 15 times to provide sets of data to analyzetimes to provide sets of data to analyzeSample mean, Sample mean, σσ22, and accuracy of the , and accuracy of the sample mean were calculated for each sample mean were calculated for each wirewire
History
Theory
Objectives
Experimental Setup
Aging
Age Analysis
Recommendations
Statistical OverviewStatistical Overview
Sample mean:Sample mean:
Sample variance:Sample variance:
Prediction of true mean:Prediction of true mean:
where is the t-estimator, is the where is the t-estimator, is the degrees of freedom, and is the accuracy degrees of freedom, and is the accuracy percentagepercentage
N
iixN
x1
1
N
iix xx
NS
1
222
1
1
N
Stxx xP,
'
Pt , P
Source: Figliola, R. S., and Beasley, D. E. Theory and Design for Mechanical Measurements. John Wiley & Sons, Inc., New York, 2000. Pgs. 121-125.
History
Theory
Objectives
Experimental Setup
Aging
Age Analysis
Recommendations
Verifying RepeatabilityVerifying Repeatability
Three new, untwisted wire specimens of Three new, untwisted wire specimens of the same length were tested (15 tests the same length were tested (15 tests each)each)The wires were cut from different The wires were cut from different spools, and the test setup was spools, and the test setup was shutdown and restarted before each shutdown and restarted before each wire was testedwire was testedThe wires were removed from the The wires were removed from the checkerboard and replaced in the same checkerboard and replaced in the same orientation between each individual test orientation between each individual test The results verify the test setup’s ability The results verify the test setup’s ability to reproduce resultsto reproduce results
History
Theory
Objectives
Experimental Setup
Aging
Age Analysis
Recommendations
Verifying RepeatabilityVerifying Repeatability
8
8.05
8.1
8.15
8.2
8.25
8.3
8.35
0 1 2 3 4
Nominal Wire Number
Me
an
Re
sp
on
se
Am
plit
ud
e (m
V)
History
Theory
Objectives
Experimental Setup
Aging
Age Analysis
Recommendations
Test ResultsTest Results
OverviewOverview– Retested wires from Fall 2002 that Retested wires from Fall 2002 that
were aged in Saltwater and Jet-A Fuelwere aged in Saltwater and Jet-A FuelNo statistically significant trendsNo statistically significant trends
– Tested five wire samples that were Tested five wire samples that were aged at high temperatures in a aged at high temperatures in a conventional ovenconventional oven
Inconclusive; needs more data pointsInconclusive; needs more data pointsHistory
Theory
Objectives
Experimental Setup
Aging
Age Analysis
Recommendations
Jet-A Fuel-Aged Wires Jet-A Fuel-Aged Wires
2.54
2.56
2.58
2.6
2.62
2.64
2.66
2.68
2.7
2.72
0 2 4 6 8 10 12
Wire Aging Sequence
Me
an
Re
sp
on
se
Am
plit
ud
e (
mV
)
History
Theory
Objectives
Experimental Setup
Aging
Age Analysis
Recommendations
Oven-Aged WiresOven-Aged Wires
2.3
2.35
2.4
2.45
2.5
2.55
2.6
2.65
2.7
0 1 2 3 4 5 6
Wire Aging Sequence
History
Theory
Objectives
Experimental Setup
Aging
Age Analysis
Recommendations
Recent DiscoveriesRecent Discoveries
Grand majority of signal being measured Grand majority of signal being measured was, in fact, EMIwas, in fact, EMI– Had thought that EMI was a significant, yet Had thought that EMI was a significant, yet
constant contributor to the measured constant contributor to the measured response signalresponse signal
– Results show fluctuations in response signal Results show fluctuations in response signal are of the correct order of magnitudeare of the correct order of magnitude
Coaxial cable that was used for most Coaxial cable that was used for most measurements was determined to be measurements was determined to be partially badpartially bad– Adds noise to signal that’s of the same order Adds noise to signal that’s of the same order
of magnitude as the triboelectric response of magnitude as the triboelectric response signal signal
History
Theory
Objectives
Experimental Setup
Aging
Age Analysis
Recommendations
Background Noise w/out Wire Background Noise w/out Wire Attached (No Excitation)Attached (No Excitation)
(This doesn’t change when the system is excited at 1kHz by the shaker.)
History
Theory
Objectives
Experimental Setup
Aging
Age Analysis
Recommendations
Background Noise w/ Wire Background Noise w/ Wire Attached (No Excitation)Attached (No Excitation)
History
Theory
Objectives
Experimental Setup
Aging
Age Analysis
Recommendations
Bare Wire ResponseBare Wire Response(No Insulation)(No Insulation)
History
Theory
Objectives
Experimental Setup
Aging
Age Analysis
Recommendations
Insulated Wire ResponseInsulated Wire Response
History
Theory
Objectives
Experimental Setup
Aging
Age Analysis
Recommendations
RecommendationsRecommendations
Refurbish aging equipmentRefurbish aging equipment– Have freezer inspected by UTHave freezer inspected by UT– Get technician from Labline to Get technician from Labline to
examine incubatorexamine incubator
Attempt further eliminate noise Attempt further eliminate noise and/or amplify Triboand/or amplify Tribo
Tension CrankTension CrankHistory
Theory
Objectives
Experimental Setup
Aging
Age Analysis
Recommendations
RecommendationsRecommendations
Buy EMF meter to determine what EMI Buy EMF meter to determine what EMI remains in testing area (specifically, remains in testing area (specifically, inside the foil enclosure) inside the foil enclosure)
Use bare wire as control Use bare wire as control – Differential amplifierDifferential amplifier
Acquire used wire from aviation scrap Acquire used wire from aviation scrap yard in Dallasyard in Dallas– Scheduling conflicts prevented this from Scheduling conflicts prevented this from
happening this semesterhappening this semester
History
Theory
Objectives
Experimental Setup
Aging
Age Analysis
Recommendations
RecommendationsRecommendations
Use HP control program to capture response Use HP control program to capture response signal for a specified time and output to Matlab signal for a specified time and output to Matlab filefile– Could then do better statistical analysis on data and Could then do better statistical analysis on data and
possibly cancel out ambient noisepossibly cancel out ambient noise
Learn new version of IdeasLearn new version of IdeasFrequency ResponseFrequency Response– Load CellLoad Cell– AmplifierAmplifier
Phase LagPhase LagVerify our conclusions with EMI-reduced setupVerify our conclusions with EMI-reduced setupFollow our outline for ageing processFollow our outline for ageing process
History
Theory
Objectives
Experimental Setup
Aging
Age Analysis
Recommendations
ConclusionConclusion
History of the ProblemHistory of the Problem
TheoryTheory
Project ObjectivesProject Objectives
Experimental SetupExperimental Setup
Lab AgingLab Aging
Age AnalysisAge Analysis
RecommendationsRecommendations
Identification of Aging Aircraft Identification of Aging Aircraft Electrical WiringElectrical Wiring
QUESTIONS ?