Strain Gage Correction for Temperature Example Apparent Strain Calibration Check Exxon Mobil Joliet Coker B 50 0 -50
Apparent Microstrain
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Temperature oF Mfg Data
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Recorded Data to Spreadsheets Example
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Stress Range per Cycle Summary Example
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Plot Stress Range for each Cycle Example
October 2003
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Histogram of Stress Ranges Example
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Histogram of Stress Ranges and Fatigue Damage Example
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Calculate Fatigue Damage for each Stress Component and Determine Cycle Life with Miner’s Rule Summation Example
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Fatigue Damage • • • • • • • • • • •
When cyclic stress is not repetitive, fatigue is addressed using a linear damage accumulation Concept by Palmgren 1924, applied by Miner in 1945 A portion of fatigue life is consumed each cycle Practical life concludes when the sum of portions equals unity ASME Design Code based on non welded samples then conservatively adjusted for welded vessels: factor of 2 on stress or 20 on cycles Fatigue Strength Reduction Factor provides additional adjustments for welded reality Coke Drums have been generally known for FSRF =2 on Design Curve FSRF not needed when peak stress modeled in finite element analysis SES applies this observation by using stress range rather than amplitude with Design Curve, in a discrete histogram summation Probabilistic Crack Growth can be calculated using a continuous model of the histogram with assumptions about stress on the ID Damage from one histogram can be compared to damage from another: Process 1 vs Process 2 Stress Engineering Services - CONFIDENTIAL
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Comparison of Fatigue Damage
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Strain Gages used for 500+ Cycles to Measure Damage Accumulation
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Stress Engineering Services Coke Drum Application Examples Richard Boswell
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Example of Probabilistic Crack Growth Calculation
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Skirt at Shell Attachment : 2 Locations at 90 deg
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Displacement after Switch during Fill Pressure and Thermal Transient Loads 1
ANSYS 5.6.2 JAN 15 2001 13:47:27 DISPLACEMENT TIME=.2 PowerGraphics EFACET=1 AVRES=Mat DMX =1.327 DSCA=12.926 ZV =1 *DIST=24.118 *XF =161.406 *YF =-14.43 Z-BUFFER EDGE
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Displacement after Switch during Quench Pressure and Thermal Transient Loads 1
ANSYS 5.6.2 JAN 15 2001 14:32:30 DISPLACEMENT TIME=1.067 PowerGraphics EFACET=1 AVRES=Mat DMX =.497393 DSCA=34.48 ZV =1 *DIST=38.274 *XF =164.652 *YF =-20.828 Z-BUFFER EDGE
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Typical Axial Peak Stress During Quench Transient 1
MX MN
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ANSYS 5.6.2 JAN 15 2001 14:26:38 NODAL SOLUTION TIME=1.067 SY (AVG) RSYS=0 PowerGraphics EFACET=1 AVRES=Mat DMX =.497393 SMN =-64558 SMX =104536 -64558 -45770 -26982 -8193 10595 29383 48171 66960 85748 104536
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Strain Gage Locations at Skirt Attachment
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SES Designed Lifting Setup for Foundation Repair
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Finite Element Model of Head and Nozzles
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Strain Gage and Thermocouples to Measure Transients on Blowdown Line Piping
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Strain Gage and Thermocouples to Measure Transients on Blowdown Line Piping
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