Problem:

While using AutoPIPE for NC calculations for equation 10a. In this equation the allowable stress relies on the stress range reduction factor which is a function of the equivalent cycle count. How does AutoPIPE calculate the Sa value without this information or if it is taking cycle count into account in another way.

Solution:

AutoPIPE's Stress summary for ASME NB has a column for number of cycles. However, when using ASME NC, the stress summary table does not have a column for number of cycles. Therefore, how does AutoPIPE evaluate the number of cycles for ASME NC analysis.

There are 2 possible answers to this question:

Answer #1:

• • Open Results Model options, see the right column, find "Range reduction factor".
  • As mentioned in the help for this setting, enter a vale of F that corresponds with the number of cycles. Consider ASME NC Table NC-3611.2(e)-1 of the code as a reference for number of cycles to Range factor (f).

Answer #2:

• • See AutoPIPE help "Fatigue Analysis (Non-ASME NB Models)". However, be aware that this will take the Tresca combined stress from the General Pipe Stress report and not the Code Stress.