The moment of inertia (second moment of area) of a circular section around any axis passing through its centroid, is given by the following expression: I = \frac{\pi R^4}{4} where R th… See more

The elastic section modulus S_xof any cross section around axis x (centroidal), describes the response of the section under elastic flexural bending. It is defined as: S_x = \frac{I_x}{… See more

The plastic section modulus is similar to the elastic one, but defined with the assumption of full plastic yielding of the cross section due to flexural bending. In that case the whole secti… See more

Radius of gyration R_gof any cross-section, relative to an axis, is given by the general formula: R_g = \sqrt{\frac{I}{A}} where I the moment of inertia of the cross-section around the … See more