**Simply Supported Beam and UDL**

A simply supported beam is a structural member that is supported at its ends and carries loads in the form of UDL (Uniformly Distributed Load). The UDL is a load that is evenly distributed along the length of the beam. When a UDL is applied to a simply supported beam, it creates different types of stresses in its cross-section.

**Types of Stresses in a Simply Supported Beam**

When a UDL is applied to a simply supported beam, it creates three types of stresses in its cross-section:

1. Shear Stress: Shear stress is the stress that acts parallel to the cross-sectional area of the beam. It is caused by the vertical loads acting on the beam and is maximum at the supports.

2. Compressive Stress: Compressive stress is the stress that acts perpendicular to the cross-sectional area of the beam. It is caused by the bending moment created by the UDL and is maximum at the top of the beam.

3. Tensile Stress: Tensile stress is the stress that acts perpendicular to the cross-sectional area of the beam. It is caused by the bending moment created by the UDL and is maximum at the bottom of the beam.

**Stresses in the Section above Neutral Axis**

The neutral axis is an imaginary line that divides the cross-section of the beam into two equal parts, the top and the bottom. In a simply supported beam carrying a UDL with a span greater than 2M, the section above the neutral axis is subjected to both shear stress and tensile stress. Here's why:

- Shear Stress: The section above the neutral axis is subjected to shear stress because the UDL creates vertical loads that act on the beam. These vertical loads create shear forces that are maximum at the supports. The section above the neutral axis experiences shear stress due to these shear forces.

- Tensile Stress: The section above the neutral axis is also subjected to tensile stress because the UDL creates a bending moment in the beam. This bending moment causes the top of the beam to be in compression and the bottom to be in tension. The section above the neutral axis experiences tensile stress due to this bending moment.

**Conclusion**

In a simply supported beam carrying a UDL with a span greater than 2M, the section above the neutral axis is subjected to both shear stress and tensile stress. The shear stress is caused by the vertical loads acting on the beam, while the tensile stress is caused by the bending moment created by the UDL. It is important to consider both these stresses when designing and analyzing simply supported beams to ensure their structural integrity and safety.

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