Fatigue Growth Sensor (FGS) System For Bridge Inspections

8/3/2019 Fatigue Growth Sensor (FGS) System For Bridge Inspections

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Non Invasive Technologies, IncNon Invasive Technologies, Inc

More Than a Billion$ of Potential Savings inMore Than a Billion$ of Potential Savings inthe US Alone Using the EFS Technologythe US Alone Using the EFS Technology


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State of BridgesState of BridgesReport by theReport by theFederalFederalHighway AdministrationHighway Administration

The continuedThe continued economic strengtheconomic strength and growth of the Unitedand growth of the UnitedStates is intimately linked to theStates is intimately linked to the strength and reliabilitystrength and reliability ofof

our highways andour highways and bridges.bridges.

The American public is experiencing the effects of an agingThe American public is experiencing the effects of an agingand deteriorating highway system.and deteriorating highway system.

IncreasedIncreased delay, discomfort, and congestion,delay, discomfort, and congestion, along withalong with

reductions in safety and servicereductions in safety and service,, are frequent.are frequent.

Highway agencies are struggling to cope with the increasingHighway agencies are struggling to cope with the increasingdemands on their highways, anddemands on their highways, and deteriorating bridges aredeteriorating bridges arebecoming more severe choke points in the system.becoming more severe choke points in the system.


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State of BridgesState of Bridges

US bridgesUS bridges 25%25% of the US bridges areof the US bridges arestructurally deficient or functionally obsolete,structurally deficient or functionally obsolete,

according to the Federal government.according to the Federal government.

Average design life of a bridge is 50 years;Average design life of a bridge is 50 years;

average age of U S bridges is currently greateraverage age of U S bridges is currently greater

than 50 yearsthan 50 years older in Europe.older in Europe.

One bridge fails each week in the U.S.One bridge fails each week in the U.S. closure orclosure orcollapse.collapse.

Leads to increased congestion and subsequentLeads to increased congestion and subsequent

pollution, economic losses, and loss of life.pollution, economic losses, and loss of life.


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Minnesota Bridge CollapseMinnesota Bridge Collapse(August 2007)(August 2007)

Fatigue cracking oneFatigue cracking oneof the leadingof the leadingsuspected causes ofsuspected causes ofthe failure.the failure.

Bringing the agingBringing the aginginfrastructure probleminfrastructure problemto the forefront.to the forefront.

Congress debatingCongress debating

how to act to protecthow to act to protectthe public.the public.

Possibility to mandatePossibility to mandatespecific technologiesspecific technologiesfor various bridgefor various bridge

problems.problems.


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The Mianus River Bridge, CTThe Mianus River Bridge, CT

II--9595 Critical East CoastCritical East CoastInterstateInterstate

Interrupted commerce andInterrupted commerce and

transportation for months.transportation for months.

Had been inspectedHad been inspected

one week prior.one week prior.

Collapse killed threeCollapse killed threeInjured dozensInjured dozens

Collapse ultimatelyCollapse ultimately

a result of a growinga result of a growing

fatigue crack.fatigue crack.


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The Mianus River Bridge, CTThe Mianus River Bridge, CT

II--9595 Critical East Coast InterstateCritical East Coast Interstate

Interrupted commerce and transportation forInterrupted commerce and transportation for

months.months.

Had been inspected one weekHad been inspected one week

prior.prior.

Collapse killed threeCollapse killed three Injured dozensInjured dozens

Collapse ultimately aCollapse ultimately a

result of aresult of a growing fatigue crackgrowing fatigue crack..

National TransportationNational TransportationSafety Board cited:Safety Board cited:

deficiencies in the State ofdeficiencies in the State ofConnecticut's bridge safetyConnecticut's bridge safetyinspection and bridgeinspection and bridge

maintenance program.maintenance program.


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The TechnologiesThe Technologies

The CHIPThe CHIP

The Fatigue Growth SensorThe Fatigue Growth Sensor

The existing technology that will be exploited by the company isThe existing technology that will be exploited by the company is

the Fatigue Growth Sensor (FGS). A second, complementarythe Fatigue Growth Sensor (FGS). A second, complementary

technology, the CHIP, is under development. Patents to protecttechnology, the CHIP, is under development. Patents to protect

both of these have been applied for to provide worldboth of these have been applied for to provide world--widewide

protection.protection.


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Over a Billion$ of Potential Savings in theOver a Billion$ of Potential Savings in theUS Alone Using the FGS TechnologyUS Alone Using the FGS Technology

Learn the status of the crack immediatelyLearn the status of the crack immediately

Learn the status of similar details on the bridgeLearn the status of similar details on the bridge

Prioritize repairsPrioritize repairs

Repair only what is neededRepair only what is needed

Verify the repair immediatelyVerify the repair immediately

Combined Process OptionsCombined Process Options TestTest

Drill stopDrill stop

Verify effectivenessVerify effectiveness


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Different from the OthersDifferent from the Others

Visual Inspection is most usedVisual Inspection is most usedinspection method.inspection method.

90%90%of cracks are missed, according toof cracks are missed, according tothe FHWA.the FHWA.

Other commonly used methods,Other commonly used methods,including eddy current and ultrasound,including eddy current and ultrasound,cannot find cracks as small as thosecannot find cracks as small as those FGSFGScan.can.

OnlyOnly FGSFGS findsfinds growinggrowing cracks; if acracks; if acrack is not growing, no signal iscrack is not growing, no signal is

produced.produced.

Thus, onlyThus, only FGSFGS can verify if a repairedcan verify if a repairedcrack is still growing or not.crack is still growing or not.

Not dependent on sound, signal to noiseNot dependent on sound, signal to noise

ratio not a problem.ratio not a problem.

The Other Methods:The Other Methods:

Eddy CurrentEddy Current

UltrasonicsUltrasonics

RadiographyRadiography

Magnetic ParticleMagnetic Particle

Dye PenetrantDye Penetrant

Acoustic EmissionAcoustic Emission


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FGSSystem BackgroundFGSSystem Background

The FGS system is a nondestructive fatigue crackThe FGS system is a nondestructive fatigue crackinspection system.inspection system.

FGS System includes: electrolyteFGS System includes: electrolyte--filled sensors, afilled sensors, aPotentiostat Data Link (PDL), an Access Point, and specialPotentiostat Data Link (PDL), an Access Point, and specialsoftware.software.


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The FGS SystemThe FGS System -- BackgroundBackground

Based on Univ. of Pennsylvania invention; developed in theBased on Univ. of Pennsylvania invention; developed in theearly 1990s, in part through sponsorship of the US Airearly 1990s, in part through sponsorship of the US AirForce.Force.

Internal and external verification (Rockwell Scientific);Internal and external verification (Rockwell Scientific);

Validation studies conducted in both laboratory and fieldValidation studies conducted in both laboratory and field(including the AAR FRA TTCI facility, and SIPS Program).(including the AAR FRA TTCI facility, and SIPS Program).

Can detect cracks as small as 0.001 in. in lab.Can detect cracks as small as 0.001 in. in lab.

Detects crack growth activity and crack growth precursors.Detects crack growth activity and crack growth precursors.

Adds significant value to all inspection and predictiveAdds significant value to all inspection and predictivemaintenance programsmaintenance programs


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Similar to an EKGSimilar to an EKG

Like an EKG:Like an EKG:

EKG (electrocardiogram)EKG (electrocardiogram) -- a test that records thea test that records theelectrical activity of the heart, shows abnormal rhythms.electrical activity of the heart, shows abnormal rhythms.

FGSFGS The Fatigue Growth SensorThe Fatigue Growth Sensor

Constant voltage applied between structure andConstant voltage applied between structure andelectrodeelectrode

Current response due to mechanical loadingCurrent response due to mechanical loading --> FGS> FGSsignalsignal

Presence of a crack alters the current flowsPresence of a crack alters the current flows


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Normal EKG

Abnormal EKG

Normal FGS

Abnormal FGS


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Fundamentals of FGSFundamentals of FGS Uses passivation of the metallic surface to measureUses passivation of the metallic surface to measure

fatigue damage:fatigue damage:

Sensor polarizes area, creates passive film.Sensor polarizes area, creates passive film.

In growing cracks, cyclic loadingIn growing cracks, cyclic loadingbreaks down passive layer.breaks down passive layer.

MicroMicro--plasticity at crack tip changes amount of exposedplasticity at crack tip changes amount of exposed

metal.metal.

As new metal is exposed,As new metal is exposed,

new, additional passive filmnew, additional passive film

forms which changes FGSforms which changes FGS

signal.signal.


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The Differential FGS SetThe Differential FGS Set--upup

An FGS sensor array is applied to an areaAn FGS sensor array is applied to an area

of interest and crack detection occurs underof interest and crack detection occurs under

or around the sensor.or around the sensor.

The Crack Measurement Sensor (CM) isThe Crack Measurement Sensor (CM) is

placed over the tip of the crack. Theplaced over the tip of the crack. TheReference Sensor (R) is placed in the sameReference Sensor (R) is placed in the same

stress field, but where there is no crack.stress field, but where there is no crack.


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The FGS System HardwareThe FGS System Hardware

FGS SensorsFGS Sensors

Measurement & ReferenceMeasurement & Reference

Customizable size, shape, geometryCustomizable size, shape, geometry

PDL (Potentiostat Data Link).PDL (Potentiostat Data Link).

Precisely controls sensor array voltagePrecisely controls sensor array voltage

Measures the current flow for the two sensorsMeasures the current flow for the two sensors

(indicator of crack condition)(indicator of crack condition)

Controls Data Acquisition Rate and DataControls Data Acquisition Rate and DataCollection Times; Stores Data LocallyCollection Times; Stores Data Locally

Wireless and battery poweredWireless and battery powered

Access Point Access Point-- Transmits data from PDL to PCTransmits data from PDL to PC


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Surface PreparationSurface Preparation Sensor InstallationSensor Installation Hardware InstallationHardware Installation

Wireless Access PointWireless Access Point Data AcquisitionData Acquisition

Typical Bridge InstallationTypical Bridge Installation


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Example InstallationsExample Installations


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Basics of Data InterpretationBasics of Data Interpretation

DifferentialDifferential FGSFGS used.used. Comparison of CM and R Sensors.Comparison of CM and R Sensors.

Ratio of the CM sensor and R sensor data used as firstRatio of the CM sensor and R sensor data used as first

decision metricdecision metric --> Energy Ratio.> Energy Ratio.

Special software uses specially designed algorithm toSpecial software uses specially designed algorithm to

determine growth activity.determine growth activity.

Possible OutputPossible Output

No GrowthNo Growth

Microplasticity (Future Initiation)Microplasticity (Future Initiation)

Active GrowthActive Growth


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The FGS SystemThe FGS System -- SoftwareSoftware

Frequency content andFrequency content andmagnitude differencesmagnitude differencesindicate crack condition.indicate crack condition.

AlgorithmAlgorithm

preliminarilypreliminarilyindicates crackindicates crack

activity status.activity status.

Results = Energy RatioResults = Energy Ratio

No growth


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Predictive Capabilities:Predictive Capabilities:Threshold Lab VerificationsThreshold Lab Verifications

Controlled environmentControlled environment

Precise measurementsPrecise measurements

Dynamic InputDynamic Input

Theoretical comparisonsTheoretical comparisons


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Experimental SetupExperimental Setup

Crack


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Fatigue DataFatigue Data

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Crack Growth DataCrack Growth Data

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Laboratory Testing ProcedureLaboratory Testing Procedure

SpecimenSpecimen Polished and PrePolished and Pre--cracked.cracked.

Crack length measured on polished surface.Crack length measured on polished surface.

Loads are determined for DK below and above DKLoads are determined for DK below and above DKthththreshold.threshold.

Tests are conducted at each of the various DK forTests are conducted at each of the various DK for10 minutes and FGS data is collected.10 minutes and FGS data is collected.

Post data collection samples are fractured and thePost data collection samples are fractured and the

crack length measured.crack length measured.


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Fracture SurfaceFracture Surface


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FGS and Threshold Bridge LoadingFGS and Threshold Bridge Loading

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FGS and ThresholdFGS and Threshold

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Energy RatioEnergy Ratio

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Energy Ratio = Ratio of Areas Under Crack Measurement andEnergy Ratio = Ratio of Areas Under Crack Measurement andReference Measurement CurvesReference Measurement Curves

Energy Ratio = 1.16Energy Ratio = 1.16

((K = 2.54 ksi inK = 2.54 ksi in


((K = 17.25 ksi inK = 17.25 ksi in


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Improving the Standard of CareImproving the Standard of Care Federal Highway AdministrationFederal Highway Administration --

Reliability of Visual InspectionReliability of Visual InspectionStudy of49 State DOT bridge inspectors.Study of49 State DOT bridge inspectors.

Multiple fatigue crack indications at multiple locationsMultiple fatigue crack indications at multiple locations

All at obviously fatigue sensitive locationsAll at obviously fatigue sensitive locations

Inspectors correctly identified the crack indications lessInspectors correctly identified the crack indications lessthan 10% of the time.than 10% of the time.

That means 90 out of every 100 fatigue cracks areThat means 90 out of every 100 fatigue cracks aremissed by conventional methodsmissed by conventional methods

Also repairs are being made 4 out of 5 times at areasAlso repairs are being made 4 out of 5 times at areaswhich do not require it (80% false positives).which do not require it (80% false positives).


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Frequency Domain OutputFrequency Domain Output

Location 1a: No Significant Activity, ER=1.3Location 1a: No Significant Activity, ER=1.3Typical Active SampleTypical Active Sample



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Predictive information available for fatigue criticalPredictive information available for fatigue critical

locations.locations.

Integrate with FASTRAN II.Integrate with FASTRAN II.

Find hotspots in all structuresFind hotspots in all structures

Bridges, aircraft, offshore platforms, ships, shipping cranesBridges, aircraft, offshore platforms, ships, shipping cranes

FGS provides additional, more useful, moreFGS provides additional, more useful, more

accurate information for decisions.accurate information for decisions.

Almost immediate repair verification.Almost immediate repair verification.

ConclusionsConclusions


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Next Steps for Product ImprovementNext Steps for Product Improvement

Crack growth rate.Crack growth rate.

Localized stress excitation method.Localized stress excitation method.

Develop fracture mechanics methodology toDevelop fracture mechanics methodology totransfer FGS into FASTRAN based code.transfer FGS into FASTRAN based code.

Develop Long Life electrolyte.Develop Long Life electrolyte.

Evaluate Parameters for7075 AL.Evaluate Parameters for7075 AL. Polarizing voltagePolarizing voltage

Threshold correlation curvesThreshold correlation curves


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Approximate Inspection CostsApproximate Inspection Costs

Costs are based on number of areas to beCosts are based on number of areas to be

inspected.inspected.

Inspection crew can cover up to ten crackInspection crew can cover up to ten cracklocations in one shift, depending on ease oflocations in one shift, depending on ease of

access.access.

For a simple two span bridge cost will beFor a simple two span bridge cost will beapproximately US$15,000.approximately US$15,000.


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Many Hundreds ofMillions ofMany Hundreds ofMillions ofPotential Savings in the US AlonePotential Savings in the US Alone

Using the EFS TechnologyUsing the EFS Technology

Potential savings from deployment of the FGSPotential savings from deployment of the FGS

system was analyzed by one U.S. state to besystem was analyzed by one U.S. state to be

about $110M.about $110M.

Deficient bridges throughout the U.S. total aboutDeficient bridges throughout the U.S. total about

150,000 (out of the total number of bridges in US150,000 (out of the total number of bridges in US

which is about 600,000).which is about 600,000).

The $110M savings for that one states deficientThe $110M savings for that one states deficient

bridges, extrapolated to the total number ofbridges, extrapolated to the total number of

deficient bridges in the entire U.S., would bedeficient bridges in the entire U.S., would be

aboutabout $1.6Billion.


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ManagementManagement Robert M. Bernstein CEONIT Inc & CoRobert M. Bernstein CEONIT Inc & Co--Chairman NIT Inc & NIT BRChairman NIT Inc & NIT BR

S.A.S.A.

Leonard Berg, CEONIT R&D Inc & CoLeonard Berg, CEONIT R&D Inc & Co--Chairman, NIT Inc & NIT BRChairman, NIT Inc & NIT BR

S.A.S.A.

Brian Austin, President, NIT R&D IncBrian Austin, President, NIT R&D Inc

William Berks, Executive ViceWilliam Berks, Executive Vice--President NIT IncPresident NIT Inc

Eric Winkler, Executive Vice President and Director ofMarketingEric Winkler, Executive Vice President and Director ofMarketing

of R&Dof R&D

Steve Swearingen, Chief TechnologyOfficer, NIT R&D IncSteve Swearingen, Chief TechnologyOfficer, NIT R&D Inc

MontyMoshier Ph.D., Chief Technologist, NIT IncMontyMoshier Ph.D., Chief Technologist, NIT Inc

Lon T. Berg, Vice President NIT R&D Inc & TreasurerLon T. Berg, Vice President NIT R&D Inc & Treasurer


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Non Invasive TechnologiesNon Invasive Technologies

IncInc

11693 San Vicente Blvd, # 91411693 San Vicente Blvd, # 914

Los Angeles, CA 90049Los Angeles, CA 90049

Tel:Tel: + 1 310 384 2428+ 1 310 384 2428

EE--mail:mail: [email protected]@noninvasivetechnologies.com

www.noninvasivetechnologies.comwww.noninvasivetechnologies.com

Documents

Fatigue Growth Sensor (FGS) System For Bridge Inspections