NCSX Web Pages  

NCSX FTP Sites  

Navigation Trail  

Handouts  

Summary  

Dahlgren is responsible for the structural analysis of the vacuum vessel.  He will start with the PDR model, updating it to the latest port configuration and structural support design.  He will use the existing two disruption load cases provided by Brooks - one for a stationary disruption and one for a 10cm VDE- for EM loads.  He will locally modify the EM loads to accommodate new ports.  Dahlgren will perform global buckling and static stress/deflection analyses for three load cases:

1. Gravity + atmospheric pressure
2. Gravity + atmospheric pressure + EM loads (stationary disruption)
3. Gravity + atmospheric pressure + EM loads (VDE)

The original (PDR) buckling analysis was done for a full 360 degree vessel with atmospheric + gravity loading only. To apply EM loads will require converting the current EM loads for a single period to cylindrical coordinates, and generating the proper grid point loading for the additional two periods (in addition to modifying the existing load set for the new port configuration)

Dahlgren will also investigate the response to unbalanced pressure loads such as might occur with neutral beams being placed in an asymmetrical pattern around the machine.  He will also perform a modal analysis using the global model to identify potentially problematic modes for dynamic loading under EM and seismic loads.

Dahlgren will develop local models of a few representative ports to analyze stresses and deflections.  Gravity loads will include a 250 lb. person stepping or hanging on the end of the port and maximum gravity loads from diagnostics hanging of the port face.  Goranson will provide maximum gravity loads from diagnostics (and other equipment hanging off the port face) based on discussions with cognizant WBS Managers. In performing the structural analysis of the ports, Dahlgren will use the latest thickness for the port extensions - Goranson reported that these had been increased in places to improve thermal performance with resistance heaters during bakeout.  A factor of two on the gravity loads will be used to simulate impulse loading during a disruption.

Discussions then shifted to global seismic analyses.  A global seismic analysis is required to define loading conditions for the vacuum vessel during a seismic event.  Once these loading conditions are determined, the global model of the vacuum vessel would be used to determine stresses and deflections in the vacuum vessel.  .Discussions will be held with Peter Titus (MIT) to explore his interest and availability to perform the global seismic analysis and to check the design basis analyses performed by Dahlgren.

Dahlgren is also responsible for developing a 3D global (half- period) model to determine thermal stresses in the shell and port extensions during the 350C bakeout.  It was unclear during the meeting how the temperature distribution in the vacuum vessel would be determined.  (Goranson and Dahlgren to resolve.)  Goranson and Freudenberg are responsible for analyses supporting the layout, spacing, and attachment of tubes on the vacuum vessel and distribution of resistance heaters on the port extensions; thermal insulation thickness; and heat leaks to the coils.  Goranson is responsible for checking (or arranging checking) of these thermal calculations.

Goranson is responsible for thermal-hydraulic analysis of the vacuum vessel heating/cooling lines.  Mike Kalish has agreed to check those calculations.

Freudenberg is responsible for analysis of the vacuum vessel supports.  Goranson is responsible for checking (or arranging checking) of these calculations.

Brooks will formally document the existing calculation for VV time constants and disruption loads. These calculations will be independently checked by Strickler.

Analysis of weld distortions is not planned.

Documentation of design basis analyses and checking thereof is required for an FDR.  Reiersen has provided guidelines for the documentation of design basis analyses.  Goranson agreed to provide a list and schedule for the documentation of the VV analyses, recognizing that they should be provided as the analyses are completed.

Summary provided by Wayne Reiersen.  Please advise where corrections are in order.

Privacy and Security Notice

Please forward comments and questions to the Webmaster