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FINAL REVIEW Landing Gear JTP Wear Test Analyses J.D. Schell GE Aircraft Engines 8-28-2001 2 HCAT Toronto Meeting Crowne Plaza Hotel August 28-30, 2001.

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Presentation on theme: "FINAL REVIEW Landing Gear JTP Wear Test Analyses J.D. Schell GE Aircraft Engines 8-28-2001 2 HCAT Toronto Meeting Crowne Plaza Hotel August 28-30, 2001."— Presentation transcript:

1 FINAL REVIEW Landing Gear JTP Wear Test Analyses J.D. Schell GE Aircraft Engines HCAT Toronto Meeting Crowne Plaza Hotel August 28-30, 2001

2 Wear Test Schematics Rod and Bushing wear test.Fretting wear test. Unctd Part (BBS):Block/Seal Bushing/Seal Coated Part (RS) : Shoe Rod

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4 Bushing Rod

5 Test Matrix Coatings vs Metal Bushings 4340 steel rods 9”x1” –EHC coated, SWA (MIL-STD-1501C, QQ-C-320B) –WC-17Co (Diam 2005) –WC-10Co-4Cr (SM5847) –HVOF by DJ2600 at Ch Pt –All ground to 8 Ra (  -in) Bushings, 64 Ra max –4340 steel, UTS –AMS 4640, Al Ni Bronze –Anodized 2024 Al, SWA (MIL-A-8625, Type 3, Class I) Coatings vs Seals Nitrile Rubber Seals –Grooved 4340 bushing –7214-FT-160-T from Green Tweed (MIL-HDBK-695C) Karon B liner in Al bronze bushing, 0.015” thick layer –Kamatics Corp. –Filled phenolic compound

6 Test Matrix (cont.)

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8 Wear Measurement Accuracy Wear Volumes from delta weight Vol = Wgt/density Densities of test matls (gm/cc) EHC = =7.83 nitrile=1.27 WC-17Co=12.2 AlNiBR=7.12 Karon B=1.51 WC-Co,Cr=13.6 anodized Al = 3.16 (up to ~3.6 max)

9 Wear Measurement (cont.) Cleanliness of specimens was an on-going source of error –isolated early occasions where heavy oil and grit in threaded and center point vee were found gave up to 0.15 gm error in weight –improved, but still easily up to 0.01 gm error when missed Due to cleanliness issues, a second method of wear assessment based on visual ratings was developed and used in addition to wgts

10 Statistical Model Wear Results for 4340 Bushings Max Measurement Error When Poor Cleaning Occurred Measurement Precision (X3)

11 Visual Appearance of Coated Rods All tested rods visually rated from 1-10 Initial L12 DOE specimens showed wide range of wear scar appeances. Picked least damaged as a 1 and worst damaged as a 10. Selected others as 2, 3, 6, 7, and 8 and adopted these as photostandards for rating rods. All rods laid out and compared side by side with the original rods of the standards (not to photos which follow)

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13 VR 2

14 VR 3

15 VR 7

16 VR10

17 Chrome and WC-Co

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19 Coatings vs Metal Bushing Summary (Avgs of Orthogonal Arrays) = Data believed to be heavily influenced by measurement errors

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21 Statistical Model Wear Results for 4340 Bushings Max Measurement Error When Poor Cleaning Occurred Measurement Precision (X3)

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24 Statistical Model Wear Results for NiAl Bronze Bushings

25 Fractional Factorial Fit with Chrome & WC-Co Coatings Estimated Effects and Coefficients for Rod Coating Wear (coded units) Term Effect Coef StDev Coef T P Constant A B C-Ctg D A*B A*C A*D Analysis of Variance for Rod (coded units) Source DF Seq SS Adj SS Adj MS F P Main Effects Way Interactions Residual Error Pure Error Total Rod Ctg Wear for L8 Baseline: Cr, WC-Co Differences in wear results are not statistically significant

26 Fractional Factorial Fit LG L8 1st Half Rep: Cr & WC-Co-Cr Ctgs Estimated Effects and Coefficients for Rod Ctg Wear (coded units) Term Effect Coef StDev Coef T P Constant A B C-Ctg D A*B A*C A*D Analysis of Variance for Rod (coded units) Source DF Seq SS Adj SS Adj MS F P Main Effects Way Interactions Residual Error Pure Error Total Ctg Wear for L8 1st Half Rep: Cr, WC-Co-Cr: Differences in wear results are not statistically significant

27 Bushing Wear with L8 Baseline: Cr,WC-Co: Differences in wear results are not statistically significant Estimated Effects and Coefficients for Bushing Wear (coded units) Term Effect Coef StDev Coef T P Constant A B C D A*B A*C A*D Analysis of Variance for Bushing (coded units) Source DF Seq SS Adj SS Adj MS F P Main Effects Way Interactions Residual Error Pure Error Total Ctg

28 Bushing Wear with L8 1st Half Rep: Cr,WC-Co-Cr Differences in wear results are not statistically significant Estimated Effects and Coefficients for Bushing Wear (coded units) Term Effect Coef StDev Coef T P Constant A B C Rod D Load A*B A*C A*D Analysis of Variance for Bushing (coded units) Source DF Seq SS Adj SS Adj MS F P Main Effects Way Interactions Residual Error Pure Error Total

29 Statistical Model Wear Results

30 Ctg Wear with L8 2nd Half Rep: Cr,WC-Co (4340,Al anodize bushings) Differences in wear results are not statistically significant Estimated Effects and Coefficients for ROD Ctg (coded units) Term Effect Coef StDev Coef T P Constant A B C-Ctg D A*B A*C A*D Analysis of Variance for ROD (coded units) Source DF Seq SS Adj SS Adj MS F P Main Effects Way Interactions Residual Error Pure Error Total

31 Bushing Wear with L8 2nd Half Rep: 4340,Al anodize Differences in wear results are not statistically significant Estimated Effects and Coefficients for BUSHING Wear (coded units) Term Effect Coef StDev Coef T P Constant A BUSHING C D A*B A*C A*D Analysis of Variance for BUSHING (coded units) Source DF Seq SS Adj SS Adj MS F P Main Effects Way Interactions Residual Error Pure Error Total

32 Coating vs Seals Summary (Avgs of Orthogonal Arrays)

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34 Statistical Model Wear Results for Nitrile Seals in 4340 Bushings

35 Estimated Effects and Coefficients for ROD CTG Wear (coded units) Term Effect Coef StDev Coef T P Constant A B C D A*B A*C A*D Analysis of Variance for ROD (coded units) Source DF Seq SS Adj SS Adj MS F P Main Effects Way Interactions Residual Error Pure Error Total Ctg Wear for L8 3rd Half Rep: Cr, WC-Co Differences in wear results are not statistically significant

36 Ctg Wear for L8 6th Half Rep: Cr,WCCoCr Differences in wear results are not statistically significant Estimated Effects and Coefficients for ROD Ctg Wear (coded units) Term Effect Coef StDev Coef T P Constant A B C D A*B A*C A*D Analysis of Variance for ROD (coded units) Source DF Seq SS Adj SS Adj MS F P Main Effects Way Interactions Residual Error Pure Error Total

37 Nitrile Wear for L8 3rd Half Rep: Cr,WC-Co Differences in wear results ARE statistically significant Estimated Effects and Coefficients for Bushing+Seal (coded units) Term Effect Coef StDev Coef T P Constant A B CTG C Seal D Load A*B A*C A*D Analysis of Variance for Bush+Seal (coded units) Source DF Seq SS Adj SS Adj MS F P Main Effects Way Interactions Residual Error Pure Error Total

38 Nitrile Wear for L8 6th Rep: Cr,WC-Co-Cr Differences in wear results are not statistically significant Estimated Effects and Coefficients for Bushing+Seal Wear (coded units) Term Effect Coef StDev Coef T P Constant A B C Seal D A*B A*C A*D Analysis of Variance for Bush+Sea (coded units) Source DF Seq SS Adj SS Adj MS F P Main Effects Way Interactions Residual Error Pure Error Total

39 Ctg Wear for L8 4th Rep: Cr,WC-Co (4340 and Karon B Bushings) Differences in wear results are not statistically significant Estimated Effects and Coefficients for BUSHING (coded units) Term Effect Coef StDev Coef T P Constant A B Ctg C Seal D A*B A*C A*D Analysis of Variance for BUSHING (coded units) Source DF Seq SS Adj SS Adj MS F P Main Effects Way Interactions Residual Error Pure Error Total

40 CONCLUSIONS Coating Wear showed very little difference between Chrome and the HVOF carbides –No statistically significant differences throughout test program Opposed Surface Wear favors Cr –Largest statistical significance with Nitrile seals WC-Co-Cr Favored over WC-Co –When statistically significant differences Karon B Wear best against all coatings


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