Specifies the bi-axial stress ratio for bends, tees, and joints. The bi-axial stress r is defined as:
where:
ssh(2:1) is the short-term hoop strength, under 2:1 stress conditions
ssa(0:1) is the short-term axial strength, under axial loading only
In the absence of data from the manufacturer, use the default values:
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Short-term |
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Bends |
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Tees |
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Other Hand laminated |
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Joints |
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You can use a higher factor for r if justified by testing according to 6.2.6 ISO 14692-2-2002. |
CAESAR II assumes that the bi-axial stress ratio r is 1.0 for tees according to ISO 14692.
CAESAR II displays a warning message in the Error Checker if the bi-axial stress ratio r is greater than 20 for bends or joints. You can ignore the warning message.
If a piping system has no joints or bends, the corresponding bi-axial stress ratio r should not be required. However, you must type a positive value (such as 1.0) for r to get rid of error messages.