Problem:
How does AutoPIPE Vessel calculate the moment arm hr for a Floating Head?
Solution:
The moment arm hr is measured from the floating head reference centerline to the centroidal location associated with the head thickness.
AutoPIPE Vessel calculates the floating head moment arm (hr) using the following formula:
hr = a−T/2
Where:
-
- a = Floating Head A Size (corroded value)
- T = Floating Head thickness (corroded value)
- hr = Moment arm used in the floating head calculations
Example
For the floating head shown below:
-
- a = 0.6875 in (corroded)
- T = 2.0 in (corroded)
hr = a−T/2 = -0.313 in
If the value of a is less than half the corroded thickness (T/2), the resulting hr will be negative.
The parameter a corresponds to the A Size entered in the Floating Head Properties dialog.