Flexural Stress

What is this formula?

The Flexural Stress formula calculates the maximum normal stress developed in a beam subjected to bending. It is one of the most important equations in structural engineering and beam design.

The equation relates the applied bending moment, the geometry of the cross section, and the location of the extreme fiber where the maximum stress occurs.

When to use it

Use this formula when analyzing:

- Steel beams

- Reinforced concrete beams

- Timber beams

- Mechanical shafts

- Structural members subjected to bending

Example

A steel beam is subjected to a bending moment of 50 kN·m.

Data:

M = 50,000 N·m

c = 0.15 m

I = 0.0025 m⁴

Formula:

σ = (M·c)/I

Substitution:

σ = (50,000 × 0.15)/0.0025

σ = 3,000,000 Pa

Result:

σ = 3.0 MPa

Applications

- Structural steel design

- Reinforced concrete analysis

- Timber engineering

- Machine component design

- Bridge engineering

- Building structures