ASME B31.3
STRESS RANGE FACTOR (§302.3.5)
The slope of the curve for the stress range factor (f)
was changed from a slope of 5:1 to a slope of 3:1
As shown below, in the range of 10k to 1 millions
cycles, the code provides a more conservative
displacement stress range allowable.
B31.3 ED. 2020
B31.3 ED. 2022
SLOPE 5:1
Date
13 February, 2023
SLOPE 3:1
123 Anywhere St.,
Any City
EXAMPLE
ALLOWABLE STRESS RANGE:
B31.3 Ed.2020 -> Sa = 0,60 x (1,25 x 138 + 0,25 x 133) = 124 MPa
B31.3 Ed.2022 -> Sa = 0,43 x (1,25 x 138 + 0,25 x 133) = 88 MPa
~30% reduction in the allowable!
EXAMPLE
ASME B31.3 ED.2020
APPROVED
ASME B31.3 ED.2022
NOT APPROVED
SOFTWARE: CAESAR II V13