Corrosion Testing for Effective Sustainment and Maintenance Practices. James Garrett, Fritz Friedersdorf, Jeff Demo,

Transcription

1 Crrsin Testing fr Effective Sustainment and Maintenance Practices James Garrett, Fritz Friedersdrf, Jeff Dem, Air Frce Crrsin Cnference June 7, 2017

2 Crrsin Testing Relates Materials t Perfrmance Crrsin, as a cmpnent f materials perfrmance, is a challenge Crrsin is difficult t test fr and measure Usage envirnments are nt clearly defined Accelerated tests have had pr crrelatin t bserved perfrmance Failure mdes f imprtance t structural integrity may nt be captured in current evaluatins Examples f aluminum crrsin damage at fastener hles (Air Frce Aging Aircraft Prgram) AA7075-T6 mass lss cupn cated by NAVAIR 2

3 Crrsin Effects In-Service and Material Develpment Overall gal fr Luna s prtfli f atmspheric crrsin prgrams is t reduce the impact f crrsin n maintenance cst and aircraft availability Apply methdlgies successfully used fr managing fatigue Need analytical methds and measurement systems t relate crrsin risk t envirnmental cnditins Envirnmental Spectra Material Respnse Quantify Severity f Service Envirnment Design Testing Service Perfrmance Establish Crrsin Risk Based n Material Perfrmance 3

4 Measurement Systems and Test Methds Measurement techniques and systems fcus n real time detectin f envirnmental parameters and atmspheric crrsin rates Envirnmental Air temp / surface temp Cntaminant lading (salts) SO 2 and NO 2 Crrsin and cating evaluatin On asset (aircraft) mnitring ANSI/NACE Standard TM fr measuring atmspheric crrsin using electrchemical sensrs 4

5 LS2A System Descriptin The mnitring system measures aluminum crrsin and envirnmental parameters within an A/C The LS2A cnsists f sensr ndes and grund statin fr data acquisitin Sensr nde includes envirnment and crrsivity sensrs Autmated data cllectin and strage n the sensr nde 16 MB f nbard memry (12 yrs f data at 30 minute intervals) Grund statin (laptp) Applicatin sftware t cllect sensr nde data via a wired r wireless interface Data stred as.csv files fr user pst prcessing LS2A Nde Grund Statin 5

6 On-bard Testing

7 Fleet Management On-Bard Aircraft Crrsin Mnitring Individual Aircraft Maintenance Crrsin severity Upset cnditins Time t next inspectin Preventive maintenance Cnditin based maintenance Lng term trends Schedule inspectins and maintenance Lad leveling amng aircraft Increase availability with ptimized thrughput Examine and ptimize fleet wide trends Supprt pre-inductin inspectin Life cycle sustainment planning Validate usage assumptins 9

8 Aircraft Mnitring System Each sensr nde includes envirnmental and crrsivity sensrs RH and air temperature sensr Cmbined sensing elements with digital utput Surface temperature sensr RTD embedded within nde enclsure material Cnductance (salt cntaminants) Gld IDE Aluminum crrsin rate Aluminum ally interdigitated electrde (IDE) 10

9 Aircraft Relative Humidity Measured RH Predicting Relative Humidity in Aircraft Predictin f aircraft RH requires sme knwledge f aircraft cnditins (A/C temp) AT 1 NOAA AT 1 RH pred RH NOAA exp exp B1 TNOAA B1 T Effective RH fr crrsin predictin depends n surface temperature air air R² = NOAA Relative Humidity R² = Predicted Aircraft RH 11

10 Relative Humidity (%) Crrsin Rate (g/m 2 /yr) Upset Cnditins Deviatin f aircraft envirnment frm expected cnditins can be an indicatin f peratinal r maintenance issues Islated instances where INU RH is much higher than expected (NOAA) RH indicate wash water intrusin INU RH NOAA RH Crr Rate /2 11/7 11/12 11/17 11/22 11/27 12/2 12/7 12/12 Date (Mnth/Day 2013) 12

11 Crrsin Rate (g/m 2 /yr) Temp ( C) / RH % Pst Flight Ops Cntribute Heavily t Crrsin High altitude flight cld saks the structure, and upn landing in a high humidity climate, cndensatin causes high crrsin Time (%) Other, 90% Pst Flt, 10% Crrsin (%) Other, 72% Pst Flt, 28% Crr Rate RH Air Temp 0.8 FLT - Pst FLT /26 5/27 5/28 5/29 5/30 5/31 6/1 6/2 6/3 13

12 Aircraft Envirnmental Usage Mnitring Air Frce F-15 dehumidificatin evaluatin (AFCPCO) Air Frce B-52 crrsin cntrl technlgy evaluatin (Luna & Being) Air Frce HH-60 demnstratin testing (AFCPCO) Air Frce Phase II SBIR AF Netwrk Aircraft Leak Detectin (Luna) Navy Integrated Hybrid Structural Management System (ONR BAA IHSMS) CH-53K Grund Test Vehicle & Phase III: (Sikrsky, NAVAIR) Navy USS Wasp/CVN Eisenhwer shipbard envirnment mnitring (NAVAIR) Navy F-18 aircraft cver evaluatin (NAVAIR) Army Capability-Based Operatins and Sustainment Technlgy Aviatin (Army BAA COST-A) Army H-60 aircraft and Sikrsky whirl stand testing (Sikrsky, Army AATD) Netherlands Aerspace Labratry mnitring NH90 rtrcraft perating in Gulf f Aden Dassault EU Clean Sky Prgram: Outdr expsure site testing 14

13 Crrsin and Leak Cntaminatin Detectin System Nvel and COTS chemical sensrs with embedded data prcessing fr lw-pwer, cntinuus envirnmental/cntaminant mnitring Integrates with a pint f maintenance data cllectin and database tl fr AC tracking Team: Mercer Engineering Research Center (MERC): Inspectin, Crrsin and Repair Reprting 3D (ICARR-3D), Pint f Maintenance tl Lckheed Martin: requirements analysis and safety f flight testing Multi-mdal sensrs fr envirnmental/chemical mnitring Wireless data transfer int the ICARR- 3D crrsin maintenance tl 15

14 LCDS System Architecture and Hardware Netwrk f n-aircraft sensrs ndes: Detectin f fuel leaks and envirnmental cntaminants Wireless cmmunicatin abilities (IEEE ) Military apprved, ff-aircraft data cllectin tablet integrated with the ICARR-3D maintenance tl sftware Wireless cmmunicatin capable Dwnlads and displays LCDS leakage and crrsin detectin Transfers data t Autmated Inspectin, Repair, Crrsin & Aircraft Tracking (AIRCAT) Database 16

15 High Sensitivity and Selectivity NO 2 sensr (SGX-4NO2) has n crss-sensitivity issues with SO 2 17

16 Atmspheric Crrsin Mdels ISO-9223 standards fr classificatin f atmspheric crrsivity can be used frm sensr readings: Suitable fr classifying the severity f utdr and sheltered envirnments Classificatin based n crrsin rate measurement f standard specimens Envirnmental classificatin is dne using time f wetness and pllutin measurements Time f wetness ( ) is based n the annual number f hurs RH is abve 80% and temperature is greater than zer degrees Celsius Airbrne salinity measured as a depsitin rate in mg/(m 2 -day) Crrsin classificatin will be recrded t ICARR-3D maintenance tl Sensr Gld Interdigitated electrde (IDE) Humidity and temperature prbe RTD prbe Aluminum Ally IDE Parameter Time f wetness (TOW Au ) Slutin resistance (R s ) Percent RH and air temperature Surface temperature Crrsin rate 19

17 Accelerated Testing

18 Cnductance (S) Wetting and Drying f a Cntaminated Surface Surface cntaminant wetting and drying has significant hysteresis due t hygrscpic salt prperties Relative Humidity (%) 21

19 Predicted Crrsin Rate (g/m 2 /y) i RMS (µa/cm 2 ) Predicting Crrsin Instantaneus crrsin rate is dependent n envirnmental cnditins Envirnmental parameters can be used t predict crrsin rate if hysteresis in wetting and drying are used t partitin the data RH (%) NaCl (mg/m 2 ) y = 0.98x R² = ANN Measured Crrsin Rate (g/m 2 /y) 22

20 CrRES System Purpse and Descriptin Cating perfrmance testing in accelerated and utdr envirnments Sensrs fr cntinuus measurements f crrsin and cating cnditin Includes mass lss and standard test panels Multi-Sensr Panel Integrated Test Rack Crrsin and Cating Evaluatin System (CrRES) Accelerated labratry test chamber r utdr expsure envirnment Standard Test Panel Dcking Platfrm Mass Lss Cupn Envirnment Assisted Cracking Mdule 23

21 Relative Humidity (%) Surface Temp ( C) Relative Humidity (%) Accelerated Cyclic Test Data Test was dne using the ASTM G85-A5 cyclic accelerated test cycle: One hur dry-ff at 35 C One hur fg at rm temperature Electrlyte: 0.05% sdium chlride and 0.35% ammnium sulfate Each dcking platfrm measures relative humidity and temperature One Cycle f G85-A5 Fg Dry-ff :00 0:30 1:00 1:30 2:00 Time (hr:min) RH Ts One week f G85-A Fg Surface Temperature ( C) Dry-ff 24

22 Free Crr (A/cm 2 ) Relative Humidity (%) Cating Perfrmance Free Crrsin Free crrsin rate f the aluminum is dependent n cating and envirnmental cnditins Chrmate primer prvided best prtectin against aluminum free crrsin The highest crrsin rates ccur during drying 1.E-07 8.E-08 6.E-08 4.E-08 2.E-08 NC-SB NC-WB CR-SB RH % 0.E Test Time (Hurs)

23 Free Crr (g/cm 2 ) Cating Perfrmance Free Crrsin The aluminum free crrsin rate can be used t determine cumulative crrsin The perfrmance cmparisns can be btained at any pint in the test 4.E-06 DP2MSP1-CS DP2MSP3-NS DP2MSP2-NW 3.E-06 2.E-06 1.E-06 0.E Test Time (Hurs) 26

24 Envirnment Assisted Cracking Mdule The EACM is used fr in situ lading f fracture samples Samples are susceptible t S-L cracking Fracture samples can be cated and scribed Crack length is measured using inductive displacement gage Instrumented Fur Pint Bend Test T S Relief ntches L Gage Sectin Plate/sheet thickness (4 L x 0.5 H x D) Crack initiatin sites Rlling Directin Cated & scribed bend test sample Crack plane Orientatin 27

25 Salt Lading + Cyclic RH (AA7075-T651) Preliminary demnstratin f ECAM instrumented fur pint bend test Spring laded t K I = 10 MPa-in 0.5 ASTM G85-A5 fr 300 hurs fr salt lading RH 30 90% 35 C static temp Peak velcities at apprximately 40% RH Instrumented Bend Test (AA7075) 28

26 Summary On-aircraft mnitring can prvide detailed infrmatin t infrm maintainers abut asset status and adjust maintenance/inspectins as needed Individual aircraft infrmatin can be rlled up t summarize fleet level trends and needs Additinal inputs such as aircraft temperature and knwledge f wetting and drying hysteresis significantly imprve aircraft crrsin predictin mdels Empirical mdels based n aircraft envirnmental parameters may prvide satisfactry predictin f crrsin rates Transient crrsin and upset cnditins can nly be detected and quantified with cntinuus individual aircraft mnitring 29

27 Cntact Inf www. LunaInc.cm/LunaLabs James Garrett Fritz Friedersdrf Jeff Dem