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2.8
Uncertainty Modelling ................................................................................................................... 2-10
2.8.1
General Description......................................................................................................... 2-10
2.9
Analysis and Results ...................................................................................................................... 2-11
2.9.1
Definition of the Reliability Index .................................................................................. 2-12
2.9.2
SN Based Fatigue Analysis ............................................................................................. 2-12
2.9.3
Calibration of Crack Growth Analysis to SN Fatigue Reliability ................................... 2-13
2.9.4
Crack Growth Analysis ................................................................................................... 2-14
2.9.5
Inspection Planning ......................................................................................................... 2-14
2.9.6
Tailor made Probability Analysis.................................................................................... 2-15
2.9.7
Sensitivity Results ........................................................................................................... 2-15
3
USERS’S GUIDE TO PROFAST ................................................................................... 3-1
3.1
Preparations for Analysis................................................................................................................. 3-2
3.2
Starting Profast................................................................................................................................. 3-2
3.2.1
Navigating the User Interface............................................................................................ 3-3
3.2.2
Initialising the Database .................................................................................................... 3-4
3.3
Definition of Fatigue Points............................................................................................................. 3-5
3.4
Modelling Uncertainties................................................................................................................... 3-8
3.4.1
Specifying Uncertainty on Input Parameters..................................................................... 3-8
3.5
Environment, Forces and Load Modelling .................................................................................... 3-12
3.5.1
Modelling Environmental Data ....................................................................................... 3-12
3.5.2
Applying Forces to a Fatigue Point ................................................................................. 3-13
3.5.3
Modelling the Long Term Stress Range Distribution ..................................................... 3-16
3.5.4
Uncertainties Applied to a Sum-Rayleigh Stress Distribution ........................................ 3-18
3.6
SN Analysis ................................................................................................................................... 3-19
3.6.1
Setting up the SN Analysis.............................................................................................. 3-19
3.6.2
SN Curves........................................................................................................................ 3-19
3.6.3
Executing the SN Analysis and Examination of Results................................................. 3-20
3.7
Crack Growth Analysis.................................................................................................................. 3-22
3.7.1
Setting up the Crack Growth Model and Geometry ........................................................ 3-22
3.7.2
Calibration of the Crack Growth Model to the SN Analysis Result ............................... 3-25
3.7.3
Running a Crack Growth Analysis and Examination of Results .................................... 3-28
3.8
Taking Inspections Into Account ................................................................................................... 3-30
3.8.1
Inspection Events............................................................................................................. 3-30
3.8.2
Inspection Quality ........................................................................................................... 3-31
3.8.3
Crack Growth Analysis After Inspection ........................................................................ 3-32
3.8.4
Taking Repair Into Account ............................................................................................ 3-32
3.9
Planning Future Inspections........................................................................................................... 3-34
3.9.1
Setting up the Plan........................................................................................................... 3-35
3.9.2
Calculating the Inspection Plan and Examination of the Plan ........................................ 3-36
3.10 Advanced Usage of Profast............................................................................................................ 3-39