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Cantilever Beam | Bending Moment and Shear Force

Cantilever beams are an essential component in construction, engineering and design projects. They are structures supported on only one end while the other end is free, making them perfect for supporting weight in areas where a projecting beam is needed. In this article, we will take a step-by-step approach to designing, installing and maintaining cantilever beams.

What is Cantilever Beam?

Cantilever Beam
Cantilever Beam

A cantilever beam is a structural member supported at one end while the other end is free. This distinctive design allows for overhanging structures without the need for additional supports. It is commonly used in construction, engineering and design projects where a projecting beam is needed to support weight.

Deflection diagram of Cantilever Beam

Deflection in Cantilever Beam
Deflection Diagram of Cantilever Beam

Bending Moment and Shear Force Diagram

Bending Moment is the algebraic sum of moments about the centroidal axis of any selected section of all the loads acting up to that particular section.

On the other hand, Shear Force is the sum total of all the vertical forces acting on a particular section of the beam.

Bending Moment and Shear Force diagram of Cantilever beam
Shear Force and Bending Moment Diagram

Cantilever Beam Bending Moment formula:

The formula for calculating the maximum bending moment in a cantilever beam is given by:

M = wL²/8

where:

M = Maximum bending moment (Nm or lb-ft),

w = Total load (N or lb),

& L = Length of the cantilever beam (m or ft)

This formula assumes that the load is evenly distributed along the length of the beam. In practice, the load may not be evenly distributed, and other factors such as the moment of inertia, the modulus of elasticity, and the shape of the cross-section of the beam may also need to be taken into account. To accurately calculate the maximum bending moment in a cantilever beam, it is best to consult with an engineer or use specialized engineering software.

Application of Cantilever Beam:

Cantilever beams are widely used in a variety of applications due to their versatility and ability to support weight. Some common applications of cantilever beams include:

1. Architectural Structures:

Cantilever beams are extensively used in architecture to create visually striking structures. Balconies, canopies, and building extensions often leverage the cantilever design to provide functional and aesthetic features without the need for additional supports.

Cantilever projection in a building

2. Diving Boards and Platforms:

Swimming pools and recreational facilities utilize cantilever beams for diving boards and platforms.

Diving board

3. Cranes and Jib Arms:

Cantilever beams are commonly used in the design of cranes and jib arms. The overhanging structure allows for efficient lifting and maneuvering of heavy loads.

Crane an example of cantilever

4. Overhead signs:

Large signs and billboards are often supported by cantilever beams, which allow the sign to project out from a building or structure and be visible from a distance.

signboard an example of cantilever

5. Aerospace Industry:

Aircraft wings often incorporate cantilever designs.

Aircraft wings an example of cantilever

6. Storage shelves:

Cantilever beams are commonly used in the construction of storage shelves, which can support heavy loads without the need for additional supports in the middle.

storage shelve a type of cantilever

You May Also Like to Read:

  1. Different types of Beam and its classification
  2. Lintel Beam – Definition, Various Types, Materials used.

FAQs on Cantilever Beam

A cantilever beam is a type of structural element that is supported on only one end while the other end is free. It projects out from a fixed support and is unsupported at the other end.
Cantilever beams are versatile and can be used in a variety of applications. They are ideal for situations where a projecting beam is needed to support weight, as they can provide additional space and stability without the need for additional supports.
The maximum bending moment in a cantilever beam is calculated by using the formula M = wL²/8, where M is the maximum bending moment, w is the total load, and L is the length of the cantilever beam.
The strength of a cantilever beam is affected by several factors, including the material used to construct the beam, the stability of its support system, and the shape of its cross-section. Other factors such as the moment of inertia, the modulus of elasticity, and the distribution of the load along the length of the beam may also need to be taken into account.
Cantilever beams are widely used in construction, engineering, and design projects, such as bridges, balconies, decks, docks, overhead signs, retaining walls, and storage shelves.

Last words:

I hope you got complete information about the Cantilever Beam in this article.

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Leave a comment if I missed anything.

Happy Learning!!

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