Shear Stress Distribution in a Rectangular Section Beam

When a rectangular section beam is loaded transversely along its length, shear stress develops in the beam. This shear stress is distributed across the cross-section of the beam, and its magnitude varies at different locations within the beam.

Shear Stress on the Top and Bottom Fibers
When a rectangular beam is loaded transversely, the shear stress is maximum at the top and bottom fibers of the beam. This is because the top and bottom fibers are farthest away from the neutral axis of the beam, resulting in a larger lever arm and thus a higher shear stress.

The shear stress distribution across the top and bottom fibers of the beam is linear, with the maximum shear stress occurring at the extreme fibers. As we move towards the neutral axis, the shear stress decreases linearly until it reaches zero at the neutral axis.

Shear Stress on the Middle Fiber
The middle fiber of the rectangular beam is located at the neutral axis, where the shear stress is zero. This is because the neutral axis is the location within the beam where the shear force passes through without causing any deformation or shear stress. Therefore, the middle fiber experiences no shear stress under transverse loading.

Shear Stress on Every Horizontal Plane
The statement that shear stress develops on every horizontal plane in the rectangular beam is incorrect. Shear stress is not distributed equally across all horizontal planes within the beam. The shear stress distribution is linear and varies from maximum at the extreme fibers to zero at the neutral axis.

Conclusion
In conclusion, when a rectangular section beam is loaded transversely along its length, shear stress develops on the top and bottom fibers of the beam. The maximum shear stress occurs at the extreme fibers, while the middle fiber experiences no shear stress. The shear stress distribution is linear, with zero shear stress at the neutral axis. It is important to consider the shear stress distribution in the design and analysis of rectangular section beams.