Shear Stress Distribution in Beams:

While  a beam is loaded, bending moment and shear force are developed at all section of the beam. In previous unit, you have already study the methods of determining shear force and bending moment in a beam section under the given load conditions. Earlier, we have seen the bending stress distribution at any cross section of the beam. We will now study the shear stress distribution at any section of the beam.

The vertical shear force at any section of a beam generates shear stress at that section. This vertical shear stress is accompanied through a horizontal shear stress of equivalent magnitude, known as complementary shear stress. Thus at any point in a cross section of the beam, there is a vertical shear stress & a horizontal shear stress of equivalent magnitude. These two shear stresses cause the diagonal tension & compression inclined at 45° to the horizontal.