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WRC107 Convention

Select this radio button if you would like to input local forces and moments in the

traditional WRC107 convention. You can choose between the WRC convention system orthe global coordinates to define the vessel, nozzle and the loads.

Both conventions allow you to enter the loads in categories such as sustained, occasionaland will compare the respective stress intensities to their allowables if at least sustained

loadings are entered. User should also specify the vessel allowables.

When you toggle between the 2 convention system, the program will attempt to convert the

loads from one system to another.

Input Loads

The following figure illustrates the WRC-107 convention system for a cylinder,

P

VC

VLMC

ML

MT

- Radial Load

- Circumferential Shear load

- Longitudinal Shear load- Circumferential Moment

- Longitudinal Moment

- Torsional Moment

In the WRC-107 convention the 3 forces P, VC and VL and the 3 moments MC, ML andMT, are defined with respect to the vessel and the nozzle orientation. So, it does not matter

if the vessel is vertical or horizontal the loads are still the same. That is benefit of this

system.

The following figure illustrates the WRC-107 convention for a sphere,

PV1

V2

M1

M2MT

- Radial Load- Shear load from points B to A

- Shear load from points D to C

- Moment from points A to B

- Moment from points D to C- Torsional Moment

For information on the global coordinate systemclick here.

Forces and Moments (SUS, EXP, OCC)

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Enter the value of nozzle forces or Moments acting on the nozzle or the attachment. Three

loading sets may be included in these calculations. Enter the loads according to each

category shown on the screen, where

SUS - Primary Loads (typically Weight+Pressure+Forces)

EXP - Secondary Loads (Thermal Expansion)OCC - Occasional Loads (typically Wind, Seismic)

When performing a finite element analysis then the loads can be entered in followingcategories: Sustained, Operating and Occasional.

Include Pressure ThrustBack to Top

Leave this field unchecked if the user DOES NOT want to include the pressure thrust force

in the nozzle axial loading. Otherwise check this field.

More information on pressure thrust is available in the article in July 2001 COADE

Newsletter.

Use Division 2 Stress IndicesBack to Top

Check this field to include the pressure stress indices described in ASME Sec. VIII Div. 2

Table AD-560.7.

This value should only be used if user intends to perform a fatigue analysis. ASME VIII

Div.2 paragraph AD-160 should be checked to see if the fatigue effect needs to be

considered. These factors are used for estimating the peak stress intensity due to internalpressure. While, the peak stress intensity due to external loads is accounted by including the

WRC 107 SIF (Kn and Kb factors).

More details are available in the user guide and in the article in June 2000 COADE

Newsletter.

Please note that the program currently DOES NOT perform the complete fatigue analysis

per Section VIII Div.2 Appendix 4 & 5 rules. Instead the value of peak stress intensity is

reported which can be used by the user to perform fatigue effect comparisons.

Use WRC 368Back to Top

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Check here to compute pressure Stresses (in Shell and Nozzle) per WRC-368. WRC-368

provides a method for calculating the stresses in cylinder to cylinder intersection (such as

cylinder-nozzle), due to internal pressure and the pressure thrust loading.

Utilizing WRC 368 along with WRC 107/297 is not very accurate for calculating the

combined stress from pressure and external loads. So, this option will only be active whenthe attachment type is roundand when no external loadsare specified.

More information on WRC-368, pressure thrust is available in the article in July 2001COADE Newsletter.

Use Kn and KbBack to Top

Check this field to include the WRC107 Stress Concentrations (Kn & Kb). The program

will estimate and use the stress concentration factors Kn and Kb per Appendix B of theWRC-107 Bulletin.

Leave this field unchecked for normal analysis (Elastic analysis). And DO NOT include the

next field "Pressure Stress Indices Per Div. 2".

This value should only be used if user intends to perform a fatigue analysis. ASME VIIIDiv.2 paragraph AD-160 should be checked to see if the fatigue effect needs to be

considered. These factors are used for estimating the peak stress intensity due to external

loads. Peak stress intensity due to internal pressure is accounted by including the Pressure

Stress Indices.

More details are available in the user guide and in the article in June 2000 COADE

Newsletter.

Please note that the program currently DOES NOT perform the complete fatigue analysisper Section VIII Div.2 Appendix 4 & 5 rules. Instead the value of peak stress intensity is

reported which can be used by the user to perform fatigue effect comparison.

Occasional Pressure DifferenceBack to Top

Enter DIFFERENCEbetween the peak pressure of the system and the system design

pressure. It shall always be a positive (or 0) entry. The additional thrust load due to thispressure difference will also be accounted for in the nozzle radial loading if the user

checked the box for "Include Pressure Thrust".

This entry will be superimposed onto the system design pressure to evaluate the primary

membrane stress due to occasional loads.

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This value is only used if the user is performing the WRC 107 analysis.