Nature of Distribution of Bending Stress

Figure Nature of stress distribution in section of a beam

It will be proved that bending stress at any layer of section of beam varies directly as distance of layer from the neutral axis. The bending stress is highest at the layer whose distance from neutral axis is highest. The bending stress is gradually reduced as neutral axis more and more becomes nearer, it becomes zero at neutral axis, and then again the bending stress gets increased in reverse direction as the distance of laver from neutral axis N - A is increased. The arrows indicating magnitudes of bending stress at different layers of section above and below the neutral axis have been given in the opposite directions to show the difference in the nature of stresses in these areas.