FINAL REVIEW Landing Gear JTP Wear Test Analyses

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FINAL REVIEWLanding Gear JTP Wear Test Analyses
2HCAT
Toronto Meeting Crowne Plaza Hotel August 28-30,
2001

• J.D. Schell
• GE Aircraft Engines
• 8-28-2001

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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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Bushing
Rod
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Test Matrix

• 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

• Coatings vs Metal Bushings
• 4340 steel rods 9x1
• 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 (m-in)
• Bushings, 64 Ra max
• 4340 steel, 260-280 UTS
• AMS 4640, Al Ni Bronze
• Anodized 2024 Al, SWA
• (MIL-A-8625, Type 3, Class I)

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Test Matrix (cont.)
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Test Matrix (cont.)
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Wear Measurement Accuracy
Densities of test matls (gm/cc) EHC
7.2 4340 7.83 nitrile1.27
WC-17Co12.2 AlNiBR7.12 Karon
B1.51 WC-Co,Cr13.6
anodized Al 3.16 (up to 3.6 max)
Wear Volumes from delta weight Vol Wgt/density
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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

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Statistical Model Wear Results for 4340 Bushings
Measurement Precision (X3)
Max Measurement Error When Poor Cleaning Occurred
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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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VR 2
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VR 3
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VR 7
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VR10
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Chrome and WC-Co
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Coatings vs Metal Bushing Summary (Avgs of
Orthogonal Arrays)
Data believed to be heavily influenced by
measurement errors
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Statistical Model Wear Results for 4340 Bushings
Measurement Precision (X3)
Max Measurement Error When Poor Cleaning Occurred
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Statistical Model Wear Results for NiAl Bronze
Bushings
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Rod Ctg Wear for L8 Baseline Cr, WC-Co
Differences in wear results are not
statistically significant
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 -0.000495 0.000235
-2.10 0.068 A 0.000037 0.000019
0.000235 0.08 0.939 B -0.000037
-0.000018 0.000235 -0.08 0.940 C-Ctg
0.000219 0.000109 0.000235 0.47 0.654 D
-0.000045 -0.000023 0.000235 -0.10
0.925 AB -0.000094 -0.000047 0.000235
-0.20 0.847 AC -0.000095 -0.000047
0.000235 -0.20 0.845 AD 0.000422
0.000211 0.000235 0.90 0.396 Analysis of
Variance for Rod (coded units) Source
DF Seq SS Adj SS Adj MS F
P Main Effects 4 0.00000021
0.00000021 0.00000005 0.06 0.992 2-Way
Interactions 3 0.00000078 0.00000078
0.00000026 0.30 0.828 Residual Error 8
0.00000707 0.00000707 0.00000088 Pure Error
8 0.00000707 0.00000707 0.00000088 Total
15 0.00000806
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Ctg Wear for L8 1st Half Rep Cr, WC-Co-Cr
Differences in wear results are not
statistically significant
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 -0.001419 0.000530
-2.68 0.028 A 0.000857 0.000428
0.000530 0.81 0.442 B -0.000377
-0.000189 0.000530 -0.36 0.731 C-Ctg
-0.001621 -0.000810 0.000530 -1.53 0.165 D
-0.000004 -0.000002 0.000530 -0.00
0.997 AB -0.000062 -0.000031 0.000530
-0.06 0.955 AC 0.000712 0.000356
0.000530 0.67 0.521 AD 0.000068
0.000034 0.000530 0.06 0.950 Analysis of
Variance for Rod (coded units) Source
DF Seq SS Adj SS Adj MS F
P Main Effects 4 0.00001401
0.00001401 0.00000350 0.78 0.568 2-Way
Interactions 3 0.00000206 0.00000206
0.00000069 0.15 0.925 Residual Error 8
0.00003592 0.00003592 0.00000449 Pure Error
8 0.00003592 0.00003592 0.00000449 Total
15 0.00005200
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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
-0.005305 0.001872 -2.83 0.022 A
-0.008400 -0.004200 0.001872 -2.24 0.055 B
0.000125 0.000062 0.001872 0.03
0.974 C -0.007712 -0.003856 0.001872
-2.06 0.073 D 0.000341 0.000170
0.001872 0.09 0.930 AB 0.001658
0.000829 0.001872 0.44 0.670 AC
-0.008178 -0.004089 0.001872 -2.18
0.060 AD 0.002326 0.001163 0.001872
0.62 0.552 Analysis of Variance for Bushing
(coded units) Source DF Seq
SS Adj SS Adj MS F P Main
Effects 4 0.00052065 0.00052065
0.00013016 2.32 0.144 2-Way Interactions 3
0.00030014 0.00030014 0.00010005 1.78
0.228 Residual Error 8 0.00044848
0.00044848 0.00005606 Pure Error 8
0.00044848 0.00044848 0.00005606 Total
15 0.00126928
Ctg
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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
-0.005136 0.002698 -1.90 0.093 A
0.003441 0.001721 0.002698 0.64 0.541 B
0.000742 0.000371 0.002698 0.14
0.894 C Rod -0.007399 -0.003699 0.002698
-1.37 0.207 D Load -0.007929 -0.003965
0.002698 -1.47 0.180 AB -0.006588
-0.003294 0.002698 -1.22 0.257 AC
0.003687 0.001844 0.002698 0.68 0.514 AD
0.002968 0.001484 0.002698 0.55
0.597 Analysis of Variance for Bushing (coded
units) Source DF Seq SS
Adj SS Adj MS F P Main Effects
4 0.0005200 0.0005200 0.00013001 1.12
0.413 2-Way Interactions 3 0.0002632
0.0002632 0.00008773 0.75 0.551 Residual Error
8 0.0009315 0.0009315 0.00011644
Pure Error 8 0.0009315 0.0009315
0.00011644 Total 15 0.0017147
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Statistical Model Wear Results
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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
-0.000479 0.000177 -2.70 0.027 A
0.000176 0.000088 0.000177 0.50 0.633 B
-0.000035 -0.000017 0.000177 -0.10
0.924 C-Ctg 0.000142 0.000071 0.000177
0.40 0.699 D 0.000054 0.000027
0.000177 0.15 0.882 AB 0.000052
0.000026 0.000177 0.15 0.887 AC
0.000012 0.000006 0.000177 0.04 0.973 AD
0.000375 0.000188 0.000177 1.06
0.321 Analysis of Variance for ROD (coded
units) Source DF Seq SS
Adj SS Adj MS F P Main Effects
4 0.00000022 0.00000022 0.00000006 0.11
0.976 2-Way Interactions 3 0.00000057
0.00000057 0.00000019 0.38 0.770 Residual
Error 8 0.00000402 0.00000402
0.00000050 Pure Error 8 0.00000402
0.00000402 0.00000050 Total 15
0.00000482
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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
-0.002698 0.001731 -1.56 0.158 A
-0.004990 -0.002495 0.001731 -1.44
0.188 BUSHING 0.005314 0.002657 0.001731
1.53 0.163 C -0.004918 -0.002459
0.001731 -1.42 0.193 D 0.004202
0.002101 0.001731 1.21 0.260 AB
0.005092 0.002546 0.001731 1.47 0.180 AC
-0.004292 -0.002146 0.001731 -1.24
0.250 AD 0.005145 0.002572 0.001731
1.49 0.176 Analysis of Variance for BUSHING
(coded units) Source DF Seq
SS Adj SS Adj MS F P Main
Effects 4 0.00037989 0.00037989
0.00009497 1.98 0.191 2-Way Interactions 3
0.00028328 0.00028328 0.00009443 1.97
0.197 Residual Error 8 0.00038364
0.00038364 0.00004796 Pure Error 8
0.00038364 0.00038364 0.00004796 Total
15 0.00104681
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Coating vs Seals Summary(Avgs of Orthogonal
Arrays)
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Statistical Model Wear Results for Nitrile Seals
in 4340 Bushings
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Ctg Wear for L8 3rd Half Rep Cr, WC-Co
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
-0.006091 0.005873 -1.04 0.330 A
0.012035 0.006017 0.005873 1.02 0.336 B
-0.011212 -0.005606 0.005873 -0.95
0.368 C 0.012282 0.006141 0.005873
1.05 0.326 D -0.011080 -0.005540
0.005873 -0.94 0.373 AB 0.011895
0.005947 0.005873 1.01 0.341 AC
-0.011135 -0.005568 0.005873 -0.95
0.371 AD 0.012467 0.006234 0.005873
1.06 0.319 Analysis of Variance for ROD (coded
units) Source DF Seq SS
Adj SS Adj MS F P Main Effects
4 0.002177 0.002177 0.0005442 0.99
0.467 2-Way Interactions 3 0.001684
0.001684 0.0005612 1.02 0.434 Residual Error
8 0.004415 0.004415 0.0005518 Pure
Error 8 0.004415 0.004415
0.0005518 Total 15 0.008275
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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
-0.000748 0.000299 -2.50 0.037 A
0.000334 0.000167 0.000299 0.56 0.591 B
0.000066 0.000033 0.000299 0.11
0.915 C -0.000531 -0.000266 0.000299
-0.89 0.400 D -0.000434 -0.000217
0.000299 -0.73 0.489 AB 0.000861
0.000431 0.000299 1.44 0.187 AC
0.000179 0.000090 0.000299 0.30 0.771 AD
-0.000429 -0.000214 0.000299 -0.72
0.493 Analysis of Variance for ROD (coded
units) Source DF Seq SS
Adj SS Adj MS F P Main Effects
4 0.00000235 0.00000235 0.00000059 0.41
0.796 2-Way Interactions 3 0.00000383
0.00000383 0.00000128 0.89 0.485 Residual
Error 8 0.00001142 0.00001142
0.00000143 Pure Error 8 0.00001142
0.00001142 0.00000143 Total 15
0.00001759
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Nitrile Wear for L8 3rd Half Rep Cr,WC-Co
Differences in wear results ARE statistically
significant
Estimated Effects and Coefficients for
BushingSeal (coded units) Term Effect
Coef StDev Coef T P Constant
-0.09341 0.01480 -6.31 0.000 A
-0.09012 -0.04506 0.01480 -3.04
0.016 B CTG -0.17611 -0.08805 0.01480
-5.95 0.000 C Seal 0.09678 0.04839
0.01480 3.27 0.011 D Load 0.12011
0.06005 0.01480 4.06 0.004 AB
-0.08003 -0.04002 0.01480 -2.70 0.027 AC
0.11162 0.05581 0.01480 3.77
0.005 AD 0.10685 0.05342 0.01480
3.61 0.007 Analysis of Variance for BushSeal
(coded units) Source DF Seq
SS Adj SS Adj MS F P Main
Effects 4 0.25171 0.25171
0.062928 17.94 0.000 2-Way Interactions 3
0.12112 0.12112 0.040373 11.51
0.003 Residual Error 8 0.02806
0.02806 0.003507 Pure Error 8
0.02806 0.02806 0.003507 Total
15 0.40088
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Nitrile Wear for L8 6th Rep Cr,WC-Co-Cr
Differences in wear results are not
statistically significant
Estimated Effects and Coefficients for
BushingSeal Wear (coded units) Term
Effect Coef StDev Coef T
P Constant -0.07231 0.02507
-2.88 0.020 A -0.01612 -0.00806
0.02507 -0.32 0.756 B -0.04219
-0.02110 0.02507 -0.84 0.425 C Seal
0.13139 0.06569 0.02507 2.62 0.031 D
-0.01512 -0.00756 0.02507 -0.30
0.771 AB 0.02540 0.01270 0.02507
0.51 0.626 AC 0.02749 0.01375
0.02507 0.55 0.598 AD 0.03405
0.01703 0.02507 0.68 0.516 Analysis of
Variance for BushSea (coded units) Source
DF Seq SS Adj SS Adj MS
F P Main Effects 4 0.078128
0.0781284 0.019532 1.94 0.197 2-Way
Interactions 3 0.010242 0.0102415
0.003414 0.34 0.798 Residual Error 8
0.080458 0.0804585 0.010057 Pure Error
8 0.080458 0.0804585 0.010057 Total
15 0.168828
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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
-0.001637 0.002061 -0.79 0.450 A
-0.005106 -0.002553 0.002061 -1.24 0.251 B
Ctg 0.007436 0.003718 0.002061 1.80
0.109 C Seal -0.007507 -0.003753 0.002061
-1.82 0.106 D 0.003680 0.001840
0.002061 0.89 0.398 AB 0.004975
0.002488 0.002061 1.21 0.262 AC
-0.004814 -0.002407 0.002061 -1.17
0.277 AD 0.002556 0.001278 0.002061
0.62 0.553 Analysis of Variance for BUSHING
(coded units) Source DF Seq
SS Adj SS Adj MS F P Main
Effects 4 0.00060503 0.00060503
0.00015126 2.22 0.156 2-Way Interactions 3
0.00021785 0.00021785 0.00007262 1.07
0.415 Residual Error 8 0.00054388
0.00054388 0.00006798 Pure Error 8
0.00054388 0.00054388 0.00006798 Total
15 0.00136675
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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