Second Moment of Area of a Circle
Second Moment of Area of a Circle
The second moment of area sets the bending stiffness and stress of a circular section such as a round bar, pin or tube.
For a solid circle I = π·d⁴/64. where d is the diameter.
Inputs
d := 40 mm=40 mm
Apply the solid-circle area-moment formula.
I := pi·d^4/64=1.26e-07 m^4
Results
It is exactly half the polar moment J. Like J it scales with the fourth power of diameter, so bending stiffness rises steeply with size.
Assumptions & limitations
- Solid circular section.
- About a centroidal diameter.
- Elastic bending theory.