Continue to Site

Eng-Tips is the largest engineering community on the Internet

Intelligent Work Forums for Engineering Professionals

  • Congratulations IDS on being selected by the Eng-Tips community for having the most helpful posts in the forums last week. Way to Go!

Load shoulder maximum capacity /

Status
Not open for further replies.

cgoncalo82

Mechanical
Nov 17, 2013
2
Hi all,

I´ve just started in a oil and gas company, already throwed to the wolves :)

In this moment I am calculating the capacities of a subsea tubing hanger running tool layout that I defined a long with my colleagues, in terms of loading shoulder capacities, stres analisys and pressures vessels.

My questions are:

1- is there a guide in the standards API 6A/ISO 13628 or do you have a calculation excel sheet based on them, in order to calculate the maximum load shoulder capacity of a certain body, concerning shoulder angle, material, contact area...?

2- the layout will be composed by a main body and then several pistons and specific guides for locking. Those pistons will move, due tu applied pressure through specific hydraulic line. I will have to calculate not only the necessary pressure to move the piston, but also if the guide wall will support the stress of the applied pressure. What should be the security factor to apply, between the maximum pressure and the maximum ID (therefore less material possible) considering the yield resistance of the material? Basically is a OD/ID calculation, applying a maximum pressure inside the body...in a material with 105 ksi, what should be the security factor? Should I only consider for example like the material had 90 ksi?

This would be a great help, have to prepare a DR for next week :)

Thank you
 
Replies continue below

Recommended for you

Hi

I have no idea what a subsea hanger running tool looks like, can you post a picture? are you working to API6A/ISO 13628?

 
You may work for a competitor, but I'll still help you. I work in oil and gas and do pretty much the same calculations on the same type of tools.
[ol 1]
[li]You may need to refer to your analysis group if you have one and see if they have a standard they use. I am not aware of one for API. Check out a book by John Fowler "Design Handbook for API6A/16A/17D Equipment". The only downside is it's pretty expensive. When you're calculating shoulder capacity, you are calculating the bearing stress. There are many factors to look at such as the angle of the shoulder, material strength, tolerances, hoop effects, impact loading, etc.
For simplicity, start by calculating projected bearing are using OD and ID of your two mating parts.
Your capacity will be Capacity=(Area*Yield Stress)/(Safety Factor) This will give you a close approximation of the capacity while being conservative. You also need a bearing factor for the load shoulder angle which you need to somehow get from your analysis group or a senior engineer.
[/li]

[li]To figure out how much pressure your guide wall can support, use von mises stress calculations that account for radial, hoop, and longitudinal stresses. Safety factor depends on either your company or you. You are the engineer making the decision. If you are unsure, do not be afraid to ask senior engineers that have more experience with calculations. Show them that you want to learn after you have exhausted your other resources.
[/li]
[/ol]

I hope this has provided a little help. This is just a start and not the whole solution. It can get pretty complicated and messy. Good Luck!
 
Status
Not open for further replies.

Part and Inventory Search

Sponsor