Enter values for the following options when WRC 297 is selected for Calculation Method. The software calculates stresses in cylindrical nozzles attached to cylindrical shells.
Loads
Sustained loads (weight+pressure+forces) are used.
The following force/moment convention is used for WRC 297:
P - Radial Force
V2 - Shear Force, D to C V1 - Shear Force, B to A M1 - Moment, B axis M2 - Moment, C axis Mt - Torsional moment
96 PV Elite User's Guide
Stress Concentration Factors
Shell Stress Concentration Factor - Enter a value, typically between 1 and 3, for stress concentration due to weld quality and dimensions in the immediate vicinity of the weld. The stress concentration factor:
Accounts for peak stresses - local stress risers in the immediate vicinity of vessel welds due to factors such as sharp corners and lack of fillet weld radii. Peak stresses are considered in fatigue analysis.
Applies to the stress calculations in the vessel and the nozzle on both the inside and the outside of the vessel.
Is used in pressure stress calculations in the vessel on both the inside and outside of the vessel.
Nozzle Stress Concentration Factor - Enter a value, typically between 1 and 3, for stress concentration due to weld quality and dimensions in the immediate vicinity of the weld. The stress concentration factor:
Accounts for peak stresses - local stress risers in the immediate vicinity of vessel welds due to factors such as sharp corners and lack of fillet weld radii. Peak stresses are considered in fatigue analysis.
Applies to the stress calculations in the vessel and the nozzle on both the inside and the outside of the vessel.
Is not used in pressure stress calculations.
Include Pressure Thrust - Select to include the pressure thrust force (P*A) in the nozzle axial load. For more information on pressure thrust, see the July 2001 COADE Newsletter
http://www.coade.com/newsletters/jul01.pdf.
Use Division 2 Stress Indices - Select to include the pressure stress indices described in ASME Sec. VIII Div. 2 Table AD-560.7. This value should only be used to perform a fatigue analysis. Check ASME VIII Div.2 paragraph AD-160 s to see if the fatigue effect needs to be considered. These factors are used for estimating the peak stress intensity due to internal pressure.
Peak stress intensity due to external loads is included in the analysis by selecting Use Kn and Kb (to find SCF). For normal (elastic) analysis, do not select this option or Use Kn and Kb (to find SCF).
The software does not perform the complete fatigue analysis of Section VIII Div.2 Appendix 4 and 5 rules. Instead, the value of peak stress intensity is reported for fatigue effect comparison. For more information, see the June 2000 COADE newsletter
http://www.coade.com/newsletters/jun00.pdf.
Weight
Home tab: Details > Weight
Adds piping and miscellaneous weight to the selected cylinder or head element. This is weight that cannot be accounted for in other commands. The weight is a static mass, not an applied force, but affects the natural frequency of the vessel and axial stress calculations. Piping weight is modeled here. The area and mass of the piping are considered in the same manner as a weight.
Previous Weight - If you created more than one weight on the element, click to go back to the previous weight.
Go To Next Weight - If you created more than one weight on the element, click to go to the next weight.
PV Elite User's Guide 97 Add New Weight - Click to add a new weight to the shell or head element.
Delete - Deletes all data for the current weight.
Common Detail Parameters (on page 65)
Layout Angle - Enter the angle between the designated zero degree reference direction on the vessel drawing and the centerline of the weight at the point where it is attached to the shell.
For a horizontal vessel, the zero degree line is at 12:00 (looking at a clock); 90 degrees is at 3:00. For a vertical vessel, the angle is more arbitrary. For purposes of rendering the graphics, the assumption is that the zero degree line is at 3:00 and 90 degrees is 12:00.
The position of the zero degree reference direction (North, West or East) and the angular rotation (clockwise or counterclockwise) are set in Tools tab, Set Configuration Parameters
, Set Default Values Tab (Configuration Dialog) (see "Set Default Values Tab (Configuration Tab)" on page 202).
If the new orientation is different from the orientation of the current model, the software asks to update the model with the new settings. If the settings are updated, the weights and areas of platforms must be recalculated:
Click List Dialog (on page 189) . On the Detail Listing dialog box, click the Platform tab so that platform data is visible. Click Platform Wind Area and Platform Weight to recalculate.
Click Platform Input for each platform. Tab through the fields in the Platform dialog box, causing the weight and area to be recalculated
The angular settings apply to nozzles, clips, legs, lifting lugs, support lugs, base rings, platforms, weights and half-pipe jackets.
Examples
Default Orientation
98 PV Elite User's Guide Angle Position: North
Rotation Direction: Clockwise
Offset from Element Centerline - Enter the distance of this weight from the centerline of vessel. The value is multiplied by the weight to obtain a moment that used in stress calculations.
For horizontal vessels, the weight is added to the saddle loads and this value is not used.
Miscellaneous Weight - Enter the weight for items such as: an attached motor or other equipment, internal piping, or external structural elements. This value is also used for seismic analysis.
Select the Active Cases for this Weight/Mass - Select the active case for the current weight/mass. You can select any combination of empty, operating, and hydro test cases.
Is this a Welded Internal? - Select if the weight is for an item that is welded to the vessel during shop construction. The weight is then added to the fabricated total weight, other weights that are functions of the fabricated total weight, and the empty total weight.
Area of External Weight/Piping/Equipment - Enter the area to use for the wind load calculation.
Piping Detail - Select Is this a Piping Detail? to include the weight and moment of overhead pipelines on vertical pressure vessels. Define the area and weight of the piping with the following options:
Pipe Lookup - Click to open the Seamless Pipe Selection dialog box and select values from the piping database for Pipe Schedule and Nominal Pipe Diameter.
Pipe Outer Diameter - Displays the OD for the pipe selected in Pipe Lookup. You can also manually enter a value.
Pipe Thickness - Displays the nominal thickness for the pipe selected in Pipe Lookup. You can also manually enter a value.
Fluid Specific Gravity - Enter the specific gravity of the contained fluid. This value is usually 1.0.
Insulation Thickness - If the pipe is insulated, enter the thickness of the insulation. If there is no insulation, enter 0.
Insulation Density - Enter the density of the pipe insulation to calculate the weight of the insulation and the moment effect.
PV Elite User's Guide 99
Compute Weight and Area - Click to calculate the pipe weight and area based on the entered values.
After weights and offsets are entered, the software calculates the overturning moment due to the eccentricity of the piping. In most designs, the piping is supported by means of braces and clips at specified intervals. The element on which the piping weight is added takes the applied load.
If piping is specified on a top head, the software attempts to graphically connect the piping to the center-most nozzle.