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NCSX Vacuum Vessel

NCSX Vacuum Vessel. Stress Analysis FDR Fred Dahlgren 17 May 2004. NCSX Vacuum Vessel Stress Analysis - FDR. Fred Dahlgren Art Brooks Peter Titus NCSX Final Design Review May 19-20, 2004 PPPL. Purpose of analysis:

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NCSX Vacuum Vessel

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  1. NCSX Vacuum Vessel Stress Analysis FDR Fred Dahlgren 17 May 2004

  2. NCSX Vacuum VesselStress Analysis - FDR Fred Dahlgren Art Brooks Peter Titus NCSX Final Design Review May 19-20, 2004 PPPL

  3. Purpose of analysis: To varify the adequacy of the vessel design and assure the design criteria are met. • Method: Finite element analysis using MSC/Nastran, Static(sol 101), Buckling(sol 105),Thermal(sol 153). • Assumptions: -Vessel & port configuration as of 2 April ‘04 Pro-E models (based on Se121-011 ver.94). -Material of shell & port nozzles and cover plates fabricated from Inconel 625 Annealed – Grade 1 sheet per ASTM B 443. -Material properties (Linear elastic, isotropic material properties) taken from the Huntington Alloys International Inconel 625 product bulletin. -Rigid vertical structural support to eliminate rigid body modes. -Preliminary static model runs assumed isothermal, 1-g gravity, 1 Atmosphere external pressure @14.7psi. Subsequent runs include nominal thermal distribution during bakeout conditions. -Disruption loads are derived from Spark ver.20b inductive solutions for a stationary center plasma and a plasma displaced 10 cm vertically up from its central equilbrium position.

  4. Material Properties(@ 200 deg.C - 392 deg.F): -Youngs Modulus 28.7e6 psi -Shear Modulus 11.1e6 psi -Poissons’ Ratio 0.286 -Density 0.305 lbs/cu. in. -Coeff. of Thermal Exp. 7.3e-6 in./in.-deg.F • Material Properties (@ 400 deg.C – 750 deg.F): -Youngs Modulus 27.1e6 psi -Shear Modulus 10.5e6 psi -Poissons’ Ratio 0.294 -Density 0.305 lbs/cu. In. -Coeff. of Thermal Exp. 7.6e-6 in./in.-deg.F (From Huntington Alloys/Specialty Metals publication for Inconel 625)

  5. Values from Pro-E Model used Material Thicknesses & port diameters for VV model ( inches): Part Thickness diameter Shell 0.375 Port 2 0.125 Port 3 0.125 Port 4 0.500 Port 6 0.250 Port 7 0.125 Port 8 0.125 Port 9 0.125 Port 10 0.125 Port 11 0.125 Port 12 0.500 Port 15 0.125 RF-Turret 0.188* Port 17 0.125 Port 18 0.125 Main Flange Dimensions: 0.65 wide x 0.85 deep, 0.375 weld

  6. NCSX VACUUM VESSEL NASTRAN 120 DEG. FEA MODEL Model Details: 38,906 DOF’s 7782 GRID POINTS 7,228 CQUAD4 1,018 CTRIA3 40 MPC’s 4 SPC’s Boundary Conditions: Cylic-Symmetry @ welded edge via MPC’s, vertically fixed @ top clevis, circumferentially top & bot. of NB port Normal Operating Loads: Uniform external 14.7 psi Gravity – 1g Temperature 200 deg.C (max.) Bakeout: 400 deg.C (max) Off-Normal (EM Disruption) Loads: 320kA Plasma @ 1.7T 210kA Plasma @ 2.0T (High Beta) 320kA Plasma @ 1.7T @dZ=10cm (Inductively coupled solutions) MPC’s (cyclic-symm.)

  7. DISPLACEMENTS FOR 1 ATMOSPHERE LOADING Run 120bbe3: 1 Atmosphere External Pressure Only

  8. Peak Shell Displacement .125” Run 120bbe3: 1 Atmosphere External Pressure Only

  9. Peak Tresca Stress @ Vertical Restraint 18 ksi Run 120bbe3: 1 Atmosphere External Pressure Only

  10. Peak Tresca Stress @Outer Surface Z2 15.2 ksi Run 120bbe3: 1 Atmosphere External Pressure Only

  11. Run 120bbe3: Tresca Stresses in the flange and weld areas are 1 to 7 ksi

  12. Added 3rd Rib .5 x 1” high Added 2 Ribs .5 x 1” high Attempts to stiffen the shell locally – not very effective

  13. Peak shell deflection 0.085 for 0.5” thk. Shell & 1 Atmosphere Load

  14. Run 120bbe3g – 1 Atmosphere External Pressure + 1g Gravity Loading

  15. 1” typ. Port-9 0.375 Port-2 Max. displacements less than 0.088” Shell Reinforcement Added internal reinforcing Tee ribs Run 120bbe2a-tribsf

  16. Peak Stress @ turret/shell 20.9 ksi Stress @ Support 18.3 ksi Tresca Stress From 1 Atmosphere + Gravity Loading Run 120bbe3g – 1 Atmosphere External Pressure + 1g Gravity Loading

  17. A cantilevered load, at various port ends, was applied via a concentrated weight of 500lbs to simulate a 250lb load at the end of the port extension ( 2x length =2x load) * Actual port end deflection with the port extension will be higher (~4x for 2x length). Max. deflection* 1.26” Run 120bbe3gf Cantilevered Loading Of Ports

  18. 34.2ksi Tresca Stress Outer Surface (Z2) Tresca Stress From 500lb Cantilevered Load on Port Ends Run 120bbe3gf – 1 Atmosphere External Pressure + 1g Gravity Loading + 500lbs cantilevered

  19. Inner Surface Tresca Stress 46.8 ksi Due To 500lb Cantilevered Load @ port18/turret intersection Run 120bbe3gf – 1 Atmosphere External Pressure + 1g Gravity Loading + 500lbs cantilevered

  20. Tresca Stress reduced below 22ksi In the turret and weld region Stress & deflection still high but below allowables in Port 18 nozzle root 27.3ksi - ~1” displacement @end Increase nozzle thickness to .188”? Run 120bbegf-2 with turret wall 0.375” thick

  21. Nominal bakeout temperature distribution: 400 deg.C uniform shell, 150 deg.C @ Port Flanges Run 120bbe2a-Thermal4 – Steady State Bakeout

  22. Total Displacements due to bakeout temperatures: 400 deg.C shell 150 deg.C at port flanges Run 120bbe2a-tstress4 – Thermal Displacements

  23. X-dir. Displacements due to bakeout temperatures: 400 deg.C shell 150 deg.C at port flanges Run 120bbe2a-tstress4 – Thermal Displacements

  24. Displacements for gravity, pressure, and bakeout temperatures: 400 deg.C shell 150 deg.C @ port flanges Run 120bbe2a-tstress4 – Thermal + Pressure + Gravity Displacements

  25. Tresca Stress Z1 Inner Surface due to gravity, pressure, and bakeout temperatures, 400 deg.C shell 150 deg.C at port flanges Run 120bbe2a-tstress4 – Thermal + Pressure + Gravity

  26. Tresca Stress Z2 Outer Surface due to gravity, pressure, and bakeout temperatures, 400 deg.C shell 150 deg.C at port flanges Run 120bbe2a-tstress4 – Thermal + Pressure + Gravity

  27. Buckling Eigenvalue = 12.99 - for 1 Atmosphere loading Run 120bbe3-buckle – Pre-load: 1 Atmosphere, Eigenvalue extraction method: Lanczos

  28. Buckling mode shape local displacement between ports 9 & 2 Run 120bbe3-buckle

  29. Poor CTRIA3 element orientation Run 120bbe3-buckle Reoriented elements produced higher critical load factor ~ 15.7 Run 120bbe2a-buckle

  30. Disruption loading (Static Runs): • VDE – 320kA plasma @ 1.7 Tesla displaced 10 cm upward • Ohmic – 320kA plasma @ 1.7 Tesla • High Beta – 210kA plasma @ 2 Tesla Note: These disruptions are assumed to occur instantaneously and utilize the fully inductive SPARK solution

  31. Force Distribution From VDE-UP(Self Forces) – 1.7 Tesla, 320kA Plasma Current Stationary @ 10cm

  32. Force Distribution From VDE-UP(External Field Forces) – 1.7 Tesla, 320kA Plasma Current Stationary @ 10cm

  33. Peak Inner Wall Shell Displacement: 0.20” Peak Outer Wall Shell Displacement: 0.25” Total Displacements Due to VDE-UP Eddy Currents + Atmospheric Pressure + Gravity Loads Run: 120bbe2a-VDE

  34. 22.2 ksi Peak Stress 17.6 ksi Tresca Stresses-Z1 (outer) Shell Surface For VDE-UP Eddy Currents + Atmospheric Pressure + Gravity Run: 120bbe2a-VDE

  35. 17.1 ksi 18.2 ksi Peak Tresca Stresses-Z2 (inner) Shell Surface For VDE-UP Eddy Currents + Atmospheric Pressure + Gravity Run: 120bbe2a-VDE

  36. Peak Stress 27.6ksi Peak Tresca Stresses-Z2 @ Flange For VDE-UP Eddy Currents + Atmospheric Pressure + Gravity Run: 120bbe2a-VDE

  37. Peak Stress 22.2ksi Peak Tresca Stresses-Z1 @ Flange For VDE-UP Eddy Currents + Atmospheric Pressure + Gravity Run: 120bbe2a-VDE

  38. Force Distribution From OHMIC(Self Forces) – 1.7 Tesla, 320kA Plasma Current Stationary

  39. Force Distribution From OHMIC (External Field Forces) – 1.7 Tesla, 320kA Plasma Current Stationary

  40. Peak Port Displacement: 0.358” Peak Displacements Outer Wall: 0.185” Peak Displacements Inner Wall: 0.130” Displacements Due to Ohmic Disruption Run: 120bbe2a-OHMIC

  41. Peak Stress 13.6 ksi Tresca Stresses-Z1 (Outer) Surface For Ohmic Eddy Currents + Atmospheric Pressure + Gravity Run: 120bbe2a-OHMIC

  42. Peak Stress 16.1 ksi Tresca Stresses-Z2 (inner) Surface For Ohmic Eddy Currents + Atmospheric Pressure + Gravity Run: 120bbe2a-OHMIC

  43. Force Distribution From HighBeta (Self Forces) – 2.0 Tesla, 320kA Plasma Current Stationary

  44. Force Distribution From HighBeta (External Field) – 2.0 Tesla, 320kA Plasma Current Stationary

  45. Peak Displacements Outer Wall: 0.166” Peak Displacements Inner Wall: 0.138” Displacements Due to High Beta Disruption Run: 120bbe2a-HighBeta

  46. Peak Stress 14.7 ksi Tresca Stresses-Z2 (inner) Shell Surface For High Beta Eddy Currents + Atmospheric Pressure + Gravity Run: 120bbe2a-HighBeta

  47. Peak Stress 16.1 ksi Tresca Stresses-Z1 (outer) Shell Surface For High Beta Eddy Currents + Atmospheric Pressure + Gravity Run: 120bbe2a-HighBeta

  48. Lowest Frequency Rocking mode ( 0.8 Hz)

  49. Dynamic loading effects due to disruptions: -Assume a worst case amplification of the most severe disruption loading: 2 x VDE Statically applied, this will be an upper bound on the structural response ( structural damping and off-resonance attenuation will produce a much less severe response). Peak Stress Z2- outer surf. 28.3 ksi Peak Stress Z1- inner surf. 29.1 ksi Run: 120bbe2a-VDE-2X

  50. Peak Tresca Z1 Stress @ interior Flange edge 47.2 ksi Peak Tresca Z2 Stress @ exterior Flange edge 49.1 ksi Run: 120bbe2a-VDE-2X

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