Half Angle Shear Stress Due to Bearing of Surfaces

[BigMoNotSmall]

Hello everyone,

In design of wellheads often the casings are hanging to each other by means of shoulders. These shoulders can be of different angles of usually 30,45 and 90 degree. The usually practice we follow here is to calculate the bearing stress in the shoulder due to the vertical load. Based on this stress half angle shear stress is calculated which is basically half of the bearing stress (for 45 degree angle). I was just trying to find out whether anyone knows what is the basis of this as I have tried to find reference of this but haven't found any. I have looked through Shigley as well but no luck.

Thank you

 

[jmec87]

The only reference I'm aware of for this method is a book by John Fowler: "Design Handbook for API 6A/16A/17D Equipment". He teaches a seminar on "Designing to API 6A, 16A, and 17D Requirements" and the handbook is included if you attend the class. You might also be able to just by the book from him without attending the class. He's been around a long time and is well-respected by many in the field, and his handbook is commonly used. See also:

http://olrengineering.com/olr.htm

(his website with details about the book and class)

https://www.eng-tips.com/viewthread.cfm?qid=355346

(other thread on Eng-Tips related to load shoulder calculations where another user mentions this book)

 

[chicopee]

If you are asking about the reason for chamfering the shoulder,then the reason is that a a shoulder with a sharp corner (90 degrees that is) could bind during the final act of positioning the whole assembly.

 

[BigMoNotSmall]

Thank you to both of you for your reply. jmec87 response is what I was after, unfortunately I dont have access to the book you have mentioned.