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Ted G. Hence, triaxial stress should not be used as a collapse criterion. The most important mechanical properties of casing and tubing are burst strength, collapse resistance and tensile strength. How to Calculate Smys. The number after alphabet represents the minimum yield strength in 1,000 psi. Evaluating Eq. For example, the pipe grade if J-55 has minimum yield strength of 55,000 psi.
The minimum collapse pressure for the plastic-to-elastic transition zone, P T , is calculated with Eq. No one wants these pipes to burst, so distribution companies pay close attention to the tensile strength of the pipes they use. It is not appropriate to calculate a von Mises stress for collapse in this case because collapse in the transitional region is not strictly a plastic yield condition.
The axial strength of the pipe body is determined by the pipe body yield strength formula found in API Bull. View all posts by DrillingFormulas.
Once pressure within a pipe reaches its yield strength, the pipe will deform and fail. Most importantly, more so than the choice of dimensional assumptions, is that the results of the triaxial analysis should be consistent with the uniaxial ratings with which they may be compared.
American Institute of Steel Construction. Multiply the pipe material's yield strength, measured in pounds per square inch, by the wall thickness, measured in inches. It may even burst, which is why the value is also known as the pipe's "burst pressure. Related Content.
Internal pressure is determined with the full evacuation above packer.
Combined burst and tension loading corresponds to the upper right-hand quadrant of the design envelope. This combined loading typically occurs when a high internal pressure is experienced because of a tubing leak or a buildup of annular pressure after the casing temperature has been increased because of production. Often, it is the change in load conditions that is most important in stress analysis.
Buckling Analysis in Deviated Wells: Yield strength equals approximately one third of the material's hardness, measured in pounds per square inch, but your manufacturer will provide an exact figure. If the outside diameter equals 10 inches, and the safety factor equals 1.