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atedionyahoo (Mechanical) (OP)
13 Jan 10 3:05
In ramber-osgood (nonlinear stress-strain) for pipeline modelling by FEA, to calculate the ramberg-osgood coefficients i need to get TENSILE STRAIN at tesile strength. How can i get TENSILE STRENGTH?, (this is at design stage and mill data is not available yet)

(NB, for ramberg osgood coefficient calculation, the required yield strain at yield strength is gotten 0.5% as per API 5L)
BigInch (Petroleum)
13 Jan 10 7:42
Specify whatever pipe you think you'll need.  There are many types of pipe to choose from.  The API 5L pipe types and properties are commonly used for pipelines.  Perhaps they will do for your application.  

http://www.woodcousa.com/line_pipe_properties.htm

Note that these properties are for a maximum temperature of 120F. You should consult your design code for property reduction requirements at other temperatures.
 

**********************
"Pumping accounts for 20% of the world's energy used by electric motors and 25-50% of the total electrical energy usage in certain industrial facilities."-DOE statistic (Note: Make that 99% for pipeline companies) http://virtualpipeline.spaces.live.com/

redpicker (Materials)
13 Jan 10 11:00
Generally, with line pipe, the "Tensile Strength" of the pipe is considered to be the "Tensile Yield" for the pipe, equal to the speciifed minimum yield strength mulitpliied by the cross sectional area (based on specified OD and wall).

In addition, for API grades anyway, the yield strength is defined by the Extension Under Load (EUL) Method, or the stress at a specified tensile strain.  For the lower grades, a strain of 0.005 is used, but this might be increased if using grades with a yield strength above around 90 KSI.  The end result is that if the grade you are using is defined with a yeild strength determined at 0.5%, then the "Tensile Strain at Tensile Strength" would be 0.005.

rp
atedionyahoo (Mechanical) (OP)
16 Jan 10 0:45
Thanks alot, I made a typo in my above question (my mistake, and sorry), in fact i need Tensile Strain at tensile strength.
Yes, in API5L for various materials, the tensile strength is specified, but tensile strain is not pointed out!, in case of any address please advise the reference. (it is in design stage and the pipe mill data is unavailable)
(0.5% strain is defined as yield strain in API5L, and i d like to know if there is such a definition for tensile strain too).
 
Struct71 (Structural)
18 Jan 10 3:57
Please see the API 5L specification appendix D (at least the 2004 version.)
atedionyahoo (Mechanical) (OP)
19 Jan 10 1:56
Thanks Struct71,
I had noted to App. D (API 5L, 2000, i do not have updated edition) it is Elongation Table.
Elongation value is the strain in which the sample (50.8mm prototype) will rupture. In Stress-Strain curve, tensile points and rupture points are different.
However, do you mean that tensile strain can be assumed the same as rupture strain (i.e. elongation)?

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