×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

Cycles N / Factor f

Cycles N / Factor f

Cycles N / Factor f

(OP)
Hello, everyone,
This question comes in my mind today suddenly.
According to B31.3, if SE<SA, the piping system could pass the displacement stress analysis.
SA=f(1.25Sc+0.25Sh) or SA=f(1.25(Sc+Sh)-SL)
Either of those two equations depends on Factor f, or say, Cycles N.
Let's assume there are two exactly same piping systems (same geometry, same pressure, same temperature). The cycles of ths first one is 7000, f=1.0. It could pass the stress analysis. The cycles of the other is 150000, f=0.5, so the SA is only half of the first one, and it may not pass stress analysis.
But when I use programs for stress analysis (CAESAR II, or something else), I just input geometry, pressure, temperature, etc. I never specified N or f.
What's the problem here?

Thanks ahead.

RE: Cycles N / Factor f

Actually "f" is an input value in CAESAR II.  The field for "f" is right next to the "Sh" (hot allowable) field.

F1 goes with SH1
F2 goes with SH2
   :
   :
F9 goes with SH9

Richard Ay
COADE, Inc.

RE: Cycles N / Factor f

Suggest you READ the manuals for the pipe stress analysis software to understand the requirements for performing a stress calc. Allowable Stress values (where f is used to calculate the stress allowable) or the actual f value are requested by all pipe stress software packages. If you never specified N or f your calcs could be incorrect unless f=1.0 (default). Remember garbage in = garbage out when using software.

RE: Cycles N / Factor f

(OP)
Thanks all of you. Is anyone familiar with ADLPIPE? and how to specify f or N in ADLPIPE?

RE: Cycles N / Factor f

The 'f' factor is an input factor in ADLPIPE as it should be with all pipe stressing software.  It is part of the code instruction and can be specified interactively when creating the load cases using the new ADLPIPE.Pro version.  

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources