The issue of allowable stress for materials
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Stress analysis reveals situations such as this: the allowable stress for A106B material is 137 MPa; under SUS conditions, the allowable stress is also 137 MPa, but it is not this value under EXP or OCC conditions. What is the direct relationship between the allowable stress and various operating conditions?
Different operating conditions result in different allowable stresses, which should be understandable. The allowable stress is related to the operating condition parameter (temperature). Also, take a look at the following post to see if it’s helpful to you. CASEARⅡ allowable stress issue: http://bbs.hcbbs.com/thread-653447-1-1.html I don’t understand CⅡ; I’ll take another closer look at various operating conditions!
Go and take a look at the book \"Stress Analysis of Pressure Pipes\" by Tang Yongjin; it contains very detailed explanations.
This post was last edited by y*e on 2010-5-28 23:59. As can be seen from the calculation results below, the allowable stresses under SUS and EXP conditions are different. The stress intensity for a single layer of film = < allowable stress; the stress intensity for both primary and secondary stresses = < 3x allowable stress. Output result: SUS condition: CODE STRESS CHECK PASSED : LOADCASE 1 (SUS) W+P1 Highest Stresses: (KPa ) CodeStress Ratio (%): 60.6 @Node 170 Code Stress: 72654.0 Allowable: 119801.3 Average Stress: 1919.6 @Node 158 Bending Stress: 72250.9 @Node 170 Torsion Stress: 4041.2 @Node 65 Hoop Stress: 1705.0 @Node 30 3D Max Intensity: 74265.9 @Node 170 EXP condition: CODE STRESS CHECK PASSED : LOADCASE 3 (EXP) L3=L2-L1 Highest Stresses: (KPa ) CodeStress Ratio (%): 50.4 @Node 38 Code Stress: 172036.4 Allowable: 341288.7 Average Stress: 3964.0 @Node 200 Bending Stress: 171287.0 @Node 38 Torsion Stress: 59463.9 @Node 220 Hoop Stress: 0.0 @Node 30 3D Max Intensity: 175594.6 @Node 38
Thank you for the suggestion from the friend on the 3rd floor; relevant information can be found in the book \"Stress Analysis of Pressure Pipes\" by Tang Yongjin.
The results vary depending on the operating conditions, and the criteria used for evaluation also differ
Why are the allowable stresses different for the primary stress checks under SUS and OCC conditions? According to the calculation results, the allowable stress for A106B material is 137,895.1 kPa under SUS conditions, 333,347.2 kPa under EXP conditions, and 183,400.5 kPa under OCC conditions. What is the relationship between the allowable stresses under the SUS/EXP/OCC three operating conditions? Piping Code: B31.3 = B31.3 -2006, May 31, 2007 CODE STRESS CHECK PASSED : LOADCASE 6 (SUS) W+P1 Highest Stresses: ( KPa ) LOADCASE 6 (SUS) W+P1 CodeStress Ratio (%): 28.0 @Node 402 Code Stress: 38570.0 Allowable: 137895.1 A*al Stress: 37153.6 @Node 400 Bending Stress: 13936.4 @Node 610 Torsion Stress: 1124.3 @Node 1000 Hoop Stress: 80058.8 @Node 400 3D Max Intensity: 99261.4 @Node 400 CODE STRESS CHECK PASSED : LOADCASE 8 (OCC) L8=L7+L6 Highest Stresses: ( KPa ) LOADCASE 8 (OCC) L8=L7+L6 CodeStress Ratio (%): 85.3 @Node 800 Code Stress: 156487.1 Allowable: 183400.5 A*al Stress: 37179.2 @Node 400 Bending Stress: 132348.5 @Node 800 Torsion Stress: 33181.6 @Node 60 Hoop Stress: 80058.8 @Node 400 3D Max Intensity: 158491.3 @Node 800 CODE STRESS CHECK PASSED : LOADCASE 12 (EXP) L12=L2-L4 Highest Stresses: ( KPa ) LOADCASE 12 (EXP) L12=L2-L4 CodeStress Ratio (%): 27.0 @Node 1100 Code Stress: 89893.7 Allowable: 333347.2 A*al Stress: 4034.5 @Node 1200 Bending Stress: 89703.4 @Node 1100 Torsion Stress: 8376.0 @Node 998 Hoop Stress: 0.0 @Node 55 3D Max Intensity: 104068.7 @Node 1100
Primary stress is denoted as ope-sus, while secondary stress is denoted as sus; different formulas are applied in these cases. B31, as well as domestic engineering standards, provide relevant formulas, with the numerical values given in the appendices. To understand the basics and the four major strength theories, it’s advisable to read books by Tang Yongjin.