Rectangular Beam under Transverse Loading

When a rectangular beam is loaded transversely, the maximum compressive stress is developed on the top layer. This can be explained as follows:

Neutral Axis

The neutral axis of a beam is an imaginary line passing through the centroid of the cross-section of the beam, where the longitudinal stress is zero.

Distribution of Stresses

When a rectangular beam is loaded transversely, the distribution of stresses is not uniform across the cross-section of the beam. The topmost layer of the beam experiences maximum compressive stress, while the bottommost layer experiences maximum tensile stress.

Reason for Maximum Compressive Stress on Top Layer

This can be explained by considering the following factors:

- When a load is applied transversely on a rectangular beam, the top layer of the beam is subjected to compressive stress, as it is in a state of confinement between the load and the neutral axis.
- The bottom layer, on the other hand, is subjected to tensile stress, as it is in a state of release or expansion due to the load.
- As a result, the topmost layer experiences maximum compressive stress, while the stress gradually reduces towards the neutral axis, where it is zero.
- Similarly, the tensile stress at the bottommost layer gradually reduces towards the neutral axis, where it is also zero.
- Thus, the maximum compressive stress is developed on the top layer of the beam, which is farthest from the neutral axis.

Conclusion

In conclusion, when a rectangular beam is loaded transversely, the maximum compressive stress is developed on the top layer of the beam. This can be attributed to the confinement of the topmost layer between the load and the neutral axis, which results in compressive stress.

See a load is acting then the bending of the beam will make a concave shape just like as U... Now in U see .. the bottom fibres are in tension while upper fibre are in compression this is also called as sagging bending. now In this case the bending causes the top fibre to contact and bottom fibre to expand.