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2.2.9.3 Specifying Design Code Data

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1) Choose Input>ASME Sec VIII Div 2 Input or click ASME Sec VIII Div 2 Input button .  The ASME Sec VIII Div 2 Data Input dialog box appears.  Because Membrane + bending + shear stress method was entered, the program automatically activated Use welded joint fatigue curve option.  Keep the default Class 1 vessel class unchanged.

 

 

2) In the Spec No. drop-down menu, choose SA-516.  The Material Selection dialog window pops up to refine the selection.

 

 

Choose SA-516 70 and click Confirm Selection button to return to previous window.

 

3) Click Edit button to open the Weld fatigue assessment data window.

 

 

The cyclic stress-strain curve describes the material model for material nonlinearity.  From the drop-down menu select the appropriate material so that the material parameters nCSS and KCSS can be retrieved by the program.  This tutorial choose Carbon Steel 20 mm weld metal.  Although 50 mm or 100 mm are closer to the design thickness 3 inches, but they are for base metal.  The weld metal is the material to be evaluated.

 

 

Enter the thickness 3 inches to account for size effect for fatigue analysis.

 

From the Statistical basis for coefficients for welded joint fatigue curves drop-down menu, choose the lower 99% Prediction Interval (–3σ).  This is the default choice for design unless otherwise agreed to by the Owner‐User and the Manufacturer.

 

 

In the Fatigue improvement group box, choose Hammer peening radio button.

 

In the Environmental modification factor fE box, leave default value 4.0 unchanged.  The environmental modification factor, fE, is typically a function of the fluid environment, loading frequency, temperature, and material variables such as grain size and chemical composition. A value of fE = 4.0 shall be used unless there is specific information to justify an alternate value based on the severity of the material/environmental interaction.

 

Because the weld is made of good quality; crack-like flaw does not exist in the weld. check Crack-like flaw does not exist radio button.

 

Click OK button to confirm and return to previous window.

 

Now the data entry is complete.  Note that the weld fatigue curve is not available for plotting.

 

Click OK to return to home window.

 

 

 

 

 

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