Additionally, in the centroid tutorial we found the centroid and hence the location of the neutral axis to be 216.29 mm from the bottom of the section. Other geometric properties used in design include area for tension, radius of gyration for compression, and moment of inertia for stiffness. The polar moment of inertia, I, of a cross section is an indication of a structural member's ability to resist torsion about an axis perpendicular to the section. Section Modulus Equations Calculators Common Shapes. In plastic analysis the neutral axis is the equal area axis. Section Modulus Calculator and equation for channel section with center neutral axis. This is shown below: This is shown below: Obviously, it is very common to require the MAXIMUM bending stress that the section experiences.

In elastic analysis the limiting elastic moment can be expressed in terms of the yield stress and the elastic section modulus, at the limit of elasticity; The plastic neutral axis is defined as the axis that splits the cross section in such a way that the compression force from the compression area is equal to the tension force from the tension area. The plastic section modulus depends on the location of the plastic neutral axis (PNA). Section Modulus Channel Section Neutral Axis at Center Equation and Calculator. Along neutral axis the stresses are zero. See a complete list of review books with similar examples.

If a bending moment M x is applied on axis x-x, the section will respond with normal stresses, varying linearly with the distance from the neutral axis (which under elastic regime coincides to the centroidal x-x axis). The PNA is defined as the axis that splits the cross section such that the compression force from the area in compression equals the tension force from the area in tension. 2.3.3 Evaluation of Plastic Moment of Resistance (M^) and Plastic Section Modulus. Usually the minimum section modulus is needed only (see next paragraph why). The polar moment of inertia for a section with respect to an axis can be calculated by: , which is valid for any channel section.