Technical library
Calculate centroidal area moments for a rectangle, circle or ideal round tube.
Method and assumptions
Rectangle: A = b h, Ix = b h³/12, Iy = h b³/12. Circle: A = πd²/4 and Ix = Iy = πd⁴/64. Round tube subtracts the inner circular section. Axes pass through the section centroid; x is parallel to the rectangle width. Results are geometry only, not load capacity or a buckling check. Example: a 20 × 10 mm rectangle has A = 200 mm² and Ix = 1666.6667 mm⁴.
