API-650 App V - Stiffener Required Inertia

[richay]

Section V.8.2.2.5 provides an equation for Ireqd (of an intermediate stiffener) with a constant of "648" in the numerator.

Section V.8.2.3.2 provides an equation for Ireqd (of an end stiffener) with a constant of "684" in the numerator.

Note that these constants are different: 648 versus 684.

I suspect one of these constants is wrong, since the "SI form" of both equation uses a constant of 37.5 ??



Richard Ay
COADE, Inc.

 

[JStephen]

This is derivable from Case 9, Table 34, Pg. 543, Formulas for Stress and Strain, 5th Edition.

I assume the 648 factor is correct. This would be 1728 (cubic inch to cubic feet conversion) divided by 8 (radius cubed to diameter cubed convesion) times 3 (safety factor).