Title Page
ABSTRACT
Contents
NOMENCLATURES 21
PREFACE 25
CHAPTER 1 TORSION OF SHAFT 28
1.1. Stress and strain 28
1.2. Torsion 30
1.3. Transmission of rotating power 35
CHAPTER 2 TORSIONAL VIBRATION MEASUREMENT METHODS 37
2.1. Torsional vibration measurement using strain gage 37
2.1.1. Principle of strain gage 37
2.1.2. Strain gage installation 40
2.1.3. Shunt calibration 49
2.2. Torsional vibration measurement using angular velocity 51
2.2.1. Introduction 51
2.2.2. Equipment for measuring angular velocity 53
CHAPTER 3 THE TRANSIENT TORSIONAL VIBRATION 59
3.1. Introduction 59
3.2. Fatigue of structures and materials 62
3.3. S-N curve 69
3.4. The calculation of cycles accumulated number for fatigue lifetime 76
CHAPTER 4 VIBRATION MONITORING AND ANALYSIS SOFTWARE USING MATLAB 80
4.1. Overview of EvamosM software 80
4.2. Running the EvamosM software 82
CHAPTER 5 CASE STUDIES 92
5.1. Barred speed range 92
5.2. Case study 1: The dynamic limiter function 97
5.3. Case study 2: The torsional vibration characteristics for 5-7 cylinders marine diesel engines during BSR passage 112
5.4. Case study 3: Fatigue lifetime estimation 118
5.5. Case study 4: Theory calculation for transient torsional vibration 140
5.5.1. Introduction 140
5.5.2. The Newmark method 141
5.5.3. Transient torsional vibration calculation for 2-stroke marine diesel engine propulsion systems 149
CHAPTER 6 CONCLUSION 167
REFERENCE 170
APPENDIX 172
Table 2.1. Setting value for F/V converter with different signal waveform 58
Table 5.1. The specification of engine and shafting system 102
Table 5.2. The specification of main engines for experiments 113
Table 5.3. The specification of engine and shafting system 118
Table 5.4. The fractional damage calculation result 135
Table 5.5. The fractional damage calculation result of BSR quick passage... 137
Table 5.6. The fractional damage calculation result of BSR steady state... 138
Table 5.7. The fractional damage calculation result of BSR steady state... 139
Table 5.8. The excitation gas pressure inside cylinder chamber for every... 145
Table 5.9. The calculation results using Newmark method 148
Table 5.10. The mass elastic model of propulsion for TV calculation in Case... 150
Table 5.11. The specification of engine and shafting system in Case study_A 151
Table 5.12. The calculated torsional stress amplitude by engine speeds at... 153
Table 5.13. The excitation gas pressure inside cylinder chamber for every... 154
Table 5.14. The mass elastic model of propulsion for TV calculation in Case... 160
Table 5.15. The mass elastic model of propulsion for TV calculation in Case... 164
Figure 1.1. Shaft in tension 28
Figure 1.2. Shaft subjected to torsion... 30
Figure 1.3. Deformation of a shaft in pure torsion 31
Figure 1.4. Deformation of an element of length dx cut... 32
Figure 1.5. Torsion failure due to tension cracking... 34
Figure 1.6. Rotating power transmission by shafts... 35
Figure 2.1. Structure of strain gage 37
Figure 2.2. Wheatstone bridge 39
Figure 2.3. Solvent degreasing 40
Figure 2.4. Surface abrading 41
Figure 2.5. Bright surface produced... 42
Figure 2.6. Neutralizing 42
Figure 2.7. Preparation before bonding 43
Figure 2.8. Bonding with adhesive 44
Figure 2.9. Tape removing 45
Figure 2.10. Soldering and wiring 46
Figure 2.11. Strain gage and the transmitter 47
Figure 2.12. Zero calibration 47
Figure 2.13. Principle diagram of torsional vibration... 48
Figure 2.14. Shunt calibration of strain gage 50
Figure 2.15. Diagram of a masses spring system 52
Figure 2.16. General schematic diagram for measuring angular velocity 53
Figure 2.17. Working principle of gap/magnetic switch sensor 54
Figure 2.18. Installation of gap/magnetic switch sensor 54
Figure 2.19. Pulse train signal received from magnetic switch sensor 55
Figure 2.20. Installation of roller encoder 56
Figure 2.21. Installation of Rotec laser tachometer 56
Figure 2.22. F/V converter ONOSOKKI FV-1500 57
Figure 3.1. Torsional vibration waveform 60
Figure 3.2. Characteristic stress level of load cycle 64
Figure 3.3. Symmetric stress 66
Figure 3.4. Skewed alternating stress 67
Figure 3.5. Repeated stress 67
Figure 3.6. Skewed alternating stress 68
Figure 3.7. The linear-log S-N curve 69
Figure 3.8. The log-log S-N curve 70
Figure 3.9. Mean stress effects 74
Figure 3.10. Empirical curves to estimate mean stress effects... 74
Figure 3.11. Number of cycles leading to failure... 77
Figure 3.12. Example for fractional damage calculation 78
Figure 3.13. S-N curve movement after time of loading 79
Figure 4.1. Schematic diagram of vibration measurement... 81
Figure 4.2. Operation interface of EvamosM software... 81
Figure 4.3. Operation interface of EvamosM software... 82
Figure 4.4. The first screen window of EvamosM S/W 83
Figure 4.5. Setting window of EvamosM S/W - Analyzer setup 83
Figure 4.6. Setting window of EvamosM S/W - Channels setup 86
Figure 4.7. Tachometer trigger levers 86
Figure 4.8. Tachometer slope 87
Figure 4.9. Setting window of EvamosM S/W... 87
Figure 4.10. Tool for converting to general text file... 89
Figure 4.11. EvamosM lite version - Setting window 90
Figure 4.12. EvamosMX version - Setting window 90
Figure 4.13. EvamosMX version - Monitoring window 91
Figure 5.1. Cumulative excitation torque generated in a typical six-... 93
Figure 5.2. An example of torsional vibration stress response... 95
Figure 5.3. BSR power margin in engine load diagram 99
Figure 5.4. The relationship between BSR power margin... 99
Figure 5.5. BSR quick passage of main engine... 103
Figure 5.6. BSR quick passage of main engine... 103
Figure 5.7. Torsional stress vibration at intermedia shaft during BSR... 106
Figure 5.8. Torsional stress vibration (AC) at intermedia shaft during BSR... 106
Figure 5.9. Torsional stress vibration at intermedia shaft during BSR... 107
Figure 5.10. Torsional stress vibration (AC) at intermedia shaft during... 107
Figure 5.11. Torsional stress vibration at intermedia shaft during BSR... 108
Figure 5.12. Torsional stress vibration (AC) at intermedia shaft during... 108
Figure 5.13. The old limiters for the governor index 110
Figure 5.14. The new limiters for the governor index (1/2) 110
Figure 5.15. The new limiters for the governor index (2/2) 111
Figure 5.16. The new limiters for BSR quick passage 111
Figure 5.17. The torsional vibration during BSR acceleration of 5... 115
Figure 5.18. The torsional vibration during BSR deceleration of 5... 115
Figure 5.19. The torsional vibration during BSR acceleration of 6... 116
Figure 5.20. The torsional vibration during BSR deceleration of 6... 116
Figure 5.21. The torsional vibration during BSR acceleration of 7... 117
Figure 5.22. The torsional vibration during BSR deceleration of 7... 117
Figure 5.23. Overview of WinGD W6X72 diesel engine 119
Figure 5.24. Strain gage with MANNER telemetry system 119
Figure 5.25. Tachometer and magnet pick-up sensor installation 120
Figure 5.26. Computer setup with EvamosM S/W 120
Figure 5.27. Schematic diagram for vibration measurement 121
Figure 5.28. The mean torsional stress determined by peak values 124
Figure 5.29. The torsional stress vibration after removing the DC... 124
Figure 5.30. Linear relationship between stress amplitude... 127
Figure 5.31. The comparison between cycle and reversal 127
Figure 5.32. Applicable load cases (stress) and associated number of... 128
Figure 5.33. The low and high cycle criteria of torsional stress for... 129
Figure 5.34. The relationship between stress amplitude... 129
Figure 5.35. Diagram of BSR quick passage tests conditions 130
Figure 5.36. The torsional vibration stress and engine speed... 131
Figure 5.37. The torsional vibration stress and engine speed... 131
Figure 5.38. The torsional vibration stress and engine speed... 132
Figure 5.39. The torsional vibration stress and engine speed... 132
Figure 5.40. The torsional vibration stress and engine speed... 133
Figure 5.41. The torsional vibration stress and engine speed... 133
Figure 5.42. The torsional vibration stress in BSR steady state condition 136
Figure 5.43. Failures on intermediate shaft due to fatigue damage 136
Figure 5.44. The Newmark method in case of α=0.25 and δ=0.5 142
Figure 5.45. The calculation method... 144
Figure 5.46. Diagram of excitation gas pressure inside cylinder chamber... 146
Figure 5.47. Mass spring diagram of propulsion system in Case study A 149
Figure 5.48. Torsional vibration calculation (orders analysis at... 152
Figure 5.49. Measured torsional vibration (orders analysis) at... 152
Figure 5.50. Diagram of excitation gas pressures for every degree... 155
Figure 5.51. The calculated transient torsional stress amplitude... 156
Figure 5.52. The measured transient torsional stress amplitude... 156
Figure 5.53. The calculated transient torsional stress amplitude... 157
Figure 5.54. The measured transient torsional stress amplitude... 157
Figure 5.55. The calculated torsional vibration stress amplitude... 158
Figure 5.56. The measured torsional vibration stress amplitude... 158
Figure 5.57. The calculated transient torsional stress amplitude... 161
Figure 5.58. The measured transient torsional stress amplitude... 161
Figure 5.59. The calculated transient torsional stress amplitude... 162
Figure 5.60. The measured transient torsional stress amplitude... 162
Figure 5.61. The calculated torsional vibration stress amplitude... 163
Figure 5.62. The measured torsional vibration stress amplitude... 163
Figure 5.63. The calculated transient torsional stress amplitude... 165
Figure 5.64. The measured transient torsional stress amplitude... 165
Figure 5.65. The calculated torsional vibration stress amplitude... 166
Figure 5.66. The measured torsional vibration stress amplitude... 166