design calculation

[prasenjith]

hello friends,

i am just a beginner to oil and gas sector . i am qc inspector and right now at the present moment i have to deal with design calculations too. i have a major doubt on api 6A ans 16A calculations. for api 6a double studded adapter i did design calculation using von mises stress for test and working pressure separately and both values is less than the minimum yield strength of the material.
and for api 16a lets say drilling spool(mud cross) 11" 5M with 2-1/16" 5m and 3-1/8' 5m outlets. for this i applied the same von misise stress calculation for the body(11") and the outlets separately and got the value less than the minimum yield stregth of the material and hence conclude design is safe within the limit.
is the methods fine ?? please help me out
thanks

 

[DSB123]

prasenjith,
If you are not familiar with design calculations then leave them to someone who knows what they are doing. Otherwise you could be spending some time in prison in the not too distant future!!

 

[jbeckhou]

Would need more information to understand your problems.

Petrotrim Services, LLC

http://www.petrotrim.com

 

[jmec87]

Hello prasenjith,
API 6A 4.3.3.3 allows the use of Von Mises for "basic pressure-vessel wall thickness" sizing (such as a straight cylindrical section with constant wall thickness) and not for calculations involving discontinuities or stress concentrations. Therefore, your methods likely do not meet the API 6A requirements.
Note the requirement in API 6A 4.6: "Design documentation shall be reviewed and verified by any qualified individual other than the individual who created the original design." This means that someone (usually an engineer) who is competent based on their training and/or experience has to review and verify the design calculations.

 

[prasenjith]

Thank you for the replies,

firstly i am just budding in the design field. the design calculation is done by myself from information gathered here and there. design documentation verification is done by the qualified persons. i just did the calculation as a support for them. Actually there is lost of confusion among each other.
The 11" 5m Drilling spool with 2-1/16 5m and 3-18 5m is the first calculation which was done by me. in that i have used the von mises energy distortion calculation for the body and outlets separately and hence got their values below the yield strength of the material (75k).
but i am not sure this method is the right one.
i would like to know all the methods to solve if any problem exist in my part

Regards