How to Calculate Slope and Deflection for a Cantilever Beam with Mixed Loadings?

In summary, the conversation discusses a problem involving a cantilever beam with a UDL and a point load. The solution involves using superposition and either integration or tabulated formulas, with the book "Strength of Materials" by J. P. Den Hartog as a helpful resource. The formulas for rotations and deflections can be found in the book.
  • #1
gk1989
8
0
I have calculated one of the 2 questions successfully with it being a simply supported beam, now i am stuck on the remaining question. Previously i have used the double integration method.

It is as follows:

"A cantilever beam, 15m long has a UDL of 25N/m acting along its entire length and a point load of 250N at the free end. If EI for the beam = 100MN/m^2 calculate the slope and deflection of the beam at the free end "

How do i include 2 different load values which are of a different format UDL & point load? and how should the answer be carried out?
 
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  • #2
Generally, superposition is the key. I have not looked at at mechanics in awhile, but I recall this being the trick.

Find the solution to one of the loadings, then find the solution due to the other loading, then sum the two solutions.

Whether you should use integration or tabulated formulas I don't know.

That depends on what your prof wants.
 
  • #3
There is a book called Strength of Materials by J. P. Den Hartog (Dover edition) that contains a table/page for rotations and deflections of a cantilever beam subject to different loadings. I do not have my book handy with me, but the formulas are so straight-forward that they can be memorized by anyone vaguely familiar with the subject:

Loading rotation deflection
moment ML/EI ML^2/2EI
Point load at end PL^2/2EI PL^3/3EI
UDL wL^3/6EI wL4/8EI

The rotations and deflections refer, of course, to the free end of the cantilever.

You can get a description of the book at :
https://www.amazon.com/dp/0486607550/?tag=pfamazon01-20
 
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1. What is Macaulay's Beam deflection?

Macaulay's Beam deflection is a mathematical method used to determine the deflection of a beam under a load. It takes into account both the load and the beam's properties, such as length, Young's modulus, and moment of inertia.

2. How is Macaulay's Beam deflection calculated?

Macaulay's Beam deflection is calculated by dividing the beam into segments and using a series of equations to determine the deflection at each segment. These equations take into account the beam's properties and the applied load.

3. What is the difference between Macaulay's Beam deflection and other methods?

Unlike other methods, Macaulay's Beam deflection takes into account the change in slope of the beam due to the applied load. This allows for a more accurate determination of the deflection at any point along the beam.

4. When is Macaulay's Beam deflection used?

Macaulay's Beam deflection is commonly used in engineering and construction to determine the deflection of beams under various loads. It is also used in the design of structures, such as bridges and buildings, to ensure they can withstand the expected loads.

5. Are there any limitations to Macaulay's Beam deflection?

While Macaulay's Beam deflection is a useful method for calculating beam deflection, it does have some limitations. It assumes that the beam is perfectly straight and elastic, which may not always be the case in real-world scenarios. It also does not take into account any structural damage or material failure that may occur under extreme loads.

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