finite element analysis of nstx flag joint design

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