Enter the centerline direction cosines. Enter values for Vessel (VX, VY, and VZ) and Attachment (NX, NY, and NZ). For WRC 107 analysis, the software uses the direction vectors to transfer the global forces and moments for each load case from piping analysis software such as CAESAR II into the traditional WRC 107 sign/load convention. For FEA, these direction cosines are used to determine the angle between the nozzle/attachment and the vessel. The direction for a conical vessel is from the big end to small end. For WRC 107 analysis, the centerlines of the vessel and nozzle must be perpendicular to each other. The direction vectors of the vessel and the nozzle centerline must not be collinear.
The following global convention system is used for a cylindrical vessel:
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The vessel direction is +Y direction Direction cosines of the vessel are:
Direction cosines of the nozzle are:
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The following global convention system is used for a spherical vessel:
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The direction of a spherical vessel is from points B to A |
The software uses these direction vectors to transfer the global forces and moments from the global convention into the traditional WRC107 convention.
Direction cosines are only available when Global is selected as the convention system. For more information, see Convention System.