×
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

Bend stiffener and intermediate flexible riser union

Bend stiffener and intermediate flexible riser union

Bend stiffener and intermediate flexible riser union

(OP)
I was questioned about the need of bend stiffeners close to the edges of intermediate flexible riser connections (rigid connections usually in repaired joints, providing transition flexible->stiff->flexible), in order to avoid damage due to excessive bending and consumption of fatigue life mainly during installation.

My first opinion was that, whether the depth and location does not provide significant dynamic bending to the pipe after it is installed, such bend stiffener will not be necessary, because the flexible pipe will not bend very much under normal installation conditions.  Furthermore, the number of cycles in higher bending loads during the installation of such an intermediate riser connection is not supposed to affect fatigue life significantly.  

However I have wondered a lot about this issue lately, I don´t feel very sure. I would like to hear someone else´s opinion or experience.

RE: Bend stiffener and intermediate flexible riser union

Andbacus,

First of all I would be very careful about rules of thumb on this issue, however I can contribute a bit.

Bendstiffener requirements and design are usually based on a dynamic analysis of the full configuration which will show both whether it is required, however also provide you design input for the stiffener. The dynamic analysis will also show any inertia effects on the mass concentration (along the line) you may have at the joint.

I agree that it is not a fatigue issue, more an extreme overbending issue (polymer and structural utilisations). If the installation method are relatively flexible you may be able to install the flexible riser without bending stiffener(s).

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