FINITE ELEMENT ANALYSIS OF NSTX FLAG JOINT

DESIGN

Irving J. Zatz

August 7, 2003

FEATURES OF FEA MODEL• INCLUDES ALL ESSENTIAL STRUCTURAL

COMPONENTS CONTRIBUTING TO FLAG JOINT PERFORMANCE– FLAGS - BOXES– COLLAR - HUBS– CENTER STACK - BOLTS– SPLINES - UMBRELLA– etc.

FEATURES OF FEA MODEL

• NON-LINEAR VARIABLE CONTACT ALONG FACE OF JOINT– CONTACT PRESSURE CAN BE

ACCURATELY MONITORED– ANY LOSS OF JOINT CONTACT CAN BE

DETECTED– FRICTION COEFFICIENT CAN BE

SPECIFIED

FEATURES OF FEA MODEL

• SHEAR KEY & PRE-LOADED BOLTS– CAN ACCURATELY DETERMINE AXIAL

AND/OR SHEAR LOAD TRANSFER TO COPPER AND INSERTS

LOAD CASES EXAMINED

• START OF FLAT TOP (SOFT)

• END OF FLAT TOP (EOFT)

• END OF PULSE (EOP)

ANALYTICAL ASSUMPTIONS

• STATIC ANALYSIS - DOES NOT ACCOUNT FOR FATIGUE AND CREEP EFFECTS

• TOLERANCES ARE PERFECT (e.g., FLAG-TO-TURN FLATNESS)

• FIT-UPS ARE PERFECT (e.g., FLAG-TO-BOX POTTING)

LOAD CASE (35)

• BOLT PRE-LOAD 5000 LBS/BOLT

• 6 kG EM LOADS-(with FLEX EFFECT)

• EOFT TEMPERATURES

• 0.4 FRICTION ASSUMED

LOAD CASE (35C)

• BOLT PRE-LOAD 5000 LBS/BOLT

• 6 kG EM LOADS-(with FLEX EFFECT)

• EOFT TEMPERATURES

• 0.2 FRICTION ASSUMED

LOAD CASE (34C)

• BOLT PRE-LOAD 5000 LBS/BOLT

• 6 kG EM LOADS-(with FLEX EFFECT)

• EOFT TEMPERATURES

• NO FRICTION ASSUMED

LOAD CASE (35B)

• BOLT PRE-LOAD 5000 LBS/BOLT

• 6 kG EM LOADS-(with FLEX EFFECT)

• SOFT TEMPERATURES

• 0.4 FRICTION ASSUMED

LOAD CASE (35D)

• BOLT PRE-LOAD 3000 LBS/BOLT

• 6 kG EM LOADS-(with FLEX EFFECT)

• SOFT TEMPERATURES

• 0.4 FRICTION ASSUMED

LOAD CASE (35E)

• BOLT PRE-LOAD 5000 LBS/BOLT

• NO EM LOADS

• END-OF-PULSE TEMPERATURES

• 0.4 FRICTION ASSUMED

SUMMARY OF RESULTS