Vessel Centerline Direction Cosines VX, VY, VZ - CAESAR II - Help

CAESAR II Users Guide (2019 Service Pack 1)

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English
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CAESAR II
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CAESAR II Version
11.0 (2019)

Specifies the direction vector or direction cosines which defines the center-line of the vessel. The nozzle direction cosines are taken from the current element's delta dimensions. The vessel cosines act as a local reference vector similar to equipment nozzles in the Nozzle Lmt Check.

For example, a vertical vessel in a Y-up coordinate system, these entries would read:

  • Vessel Centerline Direction Cosine VX - <blank>

  • Vessel Centerline Direction Cosine VY - 1.0

  • Vessel Centerline Direction Cosine VZ - <blank>

For WRC 297, API 650, and PD 5500, the nozzle element must be normal to the vessel shell. If you want to model hillside nozzles and latrolets, the first (and possibly very short) nozzle element that comes from the vessel must be perpendicular to the vessel to keep the local stiffness properly oriented. The second, longer nozzle element can then go off on the true centerline of the nozzle.

PD 5500 allows nozzles on cylinders or spheres.

Fax - Axial (Nozzle) (radial stiffness)

Mi - In-plane Bending (longitudinal stiffness)

Mo - Out-of-Plane Bending (circumferential stiffness)

Mt - Torsional (Nozzle) (torsional stiffness)

D - Direction cosine of shell

Represents a nozzle on any type of head.

Fax - Axial (Nozzle) (radial stiffness)

Mi - In-plane Bending (longitudinal stiffness)

Mo - Out-of-Plane Bending (circumferential stiffness)

Mt - Torsional (Nozzle) (torsional stiffness)

D - Direction cosine of head

  • For WRC 297, API 650, and PD 5500, if the centerlines of the nozzle and vessel are collinear, the software flags this as an error.

  • For the custom option you are not limited to radial nozzles. For Custom, you can directly define a lateral nozzle, a hillside nozzle, or a nozzle on the vessel head. The nozzle and vessel centerlines may be at varying angles to each other with a minimum angle of 20 degrees. The nozzle and vessel centerlines cannot be colinear.