NASA Technical Reports Server (NTRS) 19940020296: Investigation of the effects of manufacturing variations and materials on fatigue crack detection methods in gear teeth

118 Pages·3.9 MB·English

by  NASA Technical Reports Server (NTRS)

NASA-CR-195093 7,'- /J
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Investigation of the Effects of Manufacturing Variations
and Materials on Fatigue Crack Detection Methods in
Gear Teeth
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Jeffrey A Wheitner and Donald R. Houser
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The Ohio State University f_
Columbus, Ohio e_
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January1994
Prepared for
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Lewis Research Center
Under Grant NAG3-1147
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TABLE OF CONTENTS
Table of Contents ................................................................... v
List of Tables ....................................................................... vii
List of Figures ..................................................................... viii
Chapter I Introduction
1.1 Background .......................................................... 1
1.2 Literature Review ................................................... 3
1.3 Thesis Overview .................................................... 8
Chapter II Fatigue Crack Detection Methods
2.1 Introduction .......................................................... 10
2.2 Dye Penetrant Inspection ........................................... 10
2.3 Magnetic Particle Inspection ....................................... 12
2.4 Eddy Current Inspection ........................................... 13
2.5 Ultrasonic Inspection ............................................... 15
2.6 Radiography ......................................................... 17
2.7 System Stiffness Method ........................................... 18
2.8 Acoustic Emission ................................................... 19
2.9 Shot Peening ......................................................... 25
2.10 X-Ray Diffraction ................................................... 28
Chapter ITI Equipment and Methods
3.1 Single Tooth Bending Fatigue .................................... 29
3.2 Gear .................................................................. 29
3.3 Fixture ................................................................ 31
3.4 Fatigue Testing Machine ........................................... 36
3.5 Accelerometer ................................... :.................... 37
3.6 Spectrum Analyzer .................................................. 37
3.7 Acoustic Emission .................................................. 40
3.8 Testing Procedure ................................................... 41
3.9 Kinematic Analysis ................................................. 44
Chapter IV Results
4.1 Introduction .......................................................... 51
4.2 Nondestructive Inspection Methods .............................. 51
4.3 System Stiffness Measurements .................... .............. 52
4.4 Acoustic Emission .................................................. 56
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4.5 Residual Stress Measurements .................................... 64
4.6 Fixture Alignment ................................................... 65
4.7 Tooth Stresses ....................................................... 68
4.8 Fatigue Life Curves ................................................. 71
Chapter V Conclusions and Recommendations
5.1 Conclusions .......................................................... 77 -
5.2 Recommendations ................................................... 80
References .......................................................................... 82
Appendix A Gear Drawing SK 56249-560 ................................. 84
Appendix B Lead and Profile Ckecks ........................................ 86
Appendix C Surface Profile Traces ........................................... 92
Appendix D _ Accelerometer Specifications ................................... 96
Appendix E Computer Program for Remote Operation of
Wavetek 5820 Spectrum Analyzer ............................. 98
Appendix F Acoustic Emission Transducer Sensitivity .................... 102
Appendix G Fatigue Life Data ................................................. 104
vi
LISTOFTABLES
Table3.1 Gear Geometry and Materials ...................................... 30 -
Table3.2 Shot Peening Specifications ........................................ 31
Table4.1 Material Propertiesof GearsTested............................... 69
TableG.1 Fatigue Life Data for 4118A ....................................... 105
TableG.2 Fatigue Life Data for 4118B ....................................... 105
TableG.3 Fatigue Life Data for 4118C ....................................... 106
TableG.4 Fatigue Life Data for 9310 ......................................... 106
TableG.6 Fatigue Life Data for 9310P ....................................... 107
TableG.7 Fatigue Life Data for 8620 ......................................... 107
TableG.8 Fatigue Life Data for ADI 675 .....................................108
vii

LISTOFFIGURES
Figure2.1 Dye PenetrantInspection ......................................... 11
Figure2.2 Magnetic Particle Inspection ..................................... 12
Figure2.3 Eddy Current InspectionTechnique............................. 14
Figure2.4 Ultrasonic Inspection Method .................................... 16
Figure2.5 Acoustic Emission Parameters ................................... 21
Figure2.6 Acoustic Emission Ringdown Counts .......................... 22
Figure2.7 Stress Distribution After Shot Peening ......................... 26
Figure2.8 Effect of Self Stresses on the Bending Su'ess in a Plate ...... 27
Figure3.1 Numbered Test Gear .............................................. 32
Figure3.2 Gear Test Fixture .................................................. 33
Figure3.3 Beveled Anvil ...................................................... 36
Figure3.4 Model of Fatigue Testing System ................................ 38
Figure3.5 Schematic of Test Equipment .................................... 42
Figure3.6 Acoustic Emission Transducer Location ........................ 43
Figure3.7 i_ixture Deflections ................................................ 44
Figure3.8 Fixture Model ...................................................... 45
Figure3.9 Fixture Model Deflections at Gear Axis (,point 1) ............. 47
Figure3.10 Link B (L-Arm) .................................................... 48
Figure3.11 MTS Cylinder Seal Forces ....................................... 49
Figure4.1 System Stiffness for 4118C at 170 ksi. Root Stress .......... 54
Figure4.2 System Stiffness for 8620 at 187 ksi. Root Stress ............ 54
Figure4.3 System Stiffness for 9310 at 262 ksi. Root Stress ............ 55
viii
Figure4.4 SystemStiffnessfor 9310Pat262ksi.RootStress.......... 55
Figure4.5 AcousticEmissionCountvs.FatigueLife for4118A ........ 56
Figure4.6 AcousticEmissionCountvs.FatigueLife for 8620.......... 57
Figure4.7 AcousticEmissionCountvs.FatigueLife for 9310.......... 58
Figure4.8 AcousticEmissionCountvs.FatigueLife for 9310P.........59
Figure4.9 Exampleof Conditionsfor FailureontheCase................60
Figure4.10 Exampleof Conditionsfor FailureontheCore................61
Figure4.11 HardnessProfilesNearthe Pitch Radius....................... 61
Figure4.12 SEMof 9310GearToothShowingFatigueStriations...... 62
Figure4.13 SEMShowingCupandConeFailurein9310GearTooth...63
Figure4.14 AcousticEmissionandCrackLengthasaFunctionof
Fatigue Life ......................................................... 64
Figure4.15 StrainGageReadingsAcrossFaceWidth
(0.0004 in./in. Misalignment) .................................... 67
Figure4.16 StrainGageReadingsAcrossFaceWidth
(0.0001 in./in. Misalignment) .................................... 67
Figure4.17 Gear Root Stresses ................................................ 68
Figure4.18 RatioofFatiguePropagatioLnifetoTotalLife asa
Function of Total Life ............................................. 71
Figure4.19 FatigueLife Plot for 4118TestGears...........................72
Figure4.20 FatigueLife Plot for 9310TestGears...........................72
Figure4.21 FatigueLife Plot for 8620TestGears...........................73
Figure4.22 FatigueLife Plot for ADI 675TestGears...................... 73
Figure4.23 SEMof ADI 675GearTooth (500x) ........................... 75
FigureB.1 Profile Checksfor a 4118 Gear .................................. 87
FigureB.2 Lead Checksfor a 4118 Gear .................................... 87
FigureB.3 SurfaceTopographyfor a 4118 Gear ........................... 88
FigureB.4 Profile Checksfor an 8620Gear ................................ 88
ix
FigureB.5 Lead Checksfor an 8620 Gear ...................................89
FigureB.6 SurfaceTopographyfor an 8620Gear..........................89
FigureB.7 Profile Checksfor a 9310 Gear ..................................90
FigureB.8 Lead Checksfor a 9310 Gear .................................... 90
FigureB.9 SurfaceTopographyfor a 9310Gear........................... 91
FigureC.1 Root SurfaceFinishMeasurmentsfor 4118.Gea.r.............93
FigureC.2 Root SurfaceFinishMeasurmentsfor 8620.Gear.............94
FigureC.3 Root SurfaceFinishMeasurmentsfor 9310.Gea.r.............95
X