The section modulus () is a measure of a beam’s resistance to bending stresses. It is defined as the ratio of the moment of inertia () to the maximum distance from the neutral axis () of the beam’s cross-section. Mathematically, it can be expressed as:
where:
- = Section modulus (in meters cubed, m³)
- = Moment of inertia of the beam’s cross-sectional area (in meters to the fourth power, m⁴)
- = Distance from the neutral axis to the outermost fiber of the beam (in meters, m)