What is the maximum bending moment for this beam?

In summary: When determining the support reactions, the UDL can be represented by a single concentrated load of 11,200 N acting at the center of gravity of UDL, that is, at (a + l)/2 from the left end of the beam.
  • #1
Antex
3
0

Homework Statement



Problem: For the beam according to the image, solve graphical and analytical:

1.) Reactions in the supports,
2.) Bending moment diagram,
3.) Maximum bending moment

Given variables:
F = 14 kN
q = 40 N/cm
a = 100 cm
b = 55 cm
l = 180 cm

TS2dfMZ.png

Homework Equations


This is a Beam with both overhanging supports, with a UDL and a point load on the right overhang. And I cannot find information for solving this.

Sorry for my terminology, I am doing physics in another language.

I am having a lot of trouble with the solving of this problem. What really confuses me is the UDL (I hope this is the correct terminology) that isn't over the entire beam, but hangs off on the left side.

I can't find any problems in my book that solve this kind of problem, and the professor didn't go into detail.

The Attempt at a Solution



This is a Beam with both overhanging supports, with a UDL and a point load on the right overhang.

My attempt at this was trying to figure out the force F[itex]_{q}[/itex], with: F[itex]_{q}[/itex] = q*l => 40 * 280 = 11200 N/cm, 112 N/m, 0,112 kN/m

And assuming that the above is correct, which I do not know, I can go ahead and find F[itex]_{A}[/itex] and F[itex]_{B}[/itex]
 
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  • #2
Antex said:
My attempt at this was trying to figure out the force F[itex]_{q}[/itex], with: F[itex]_{q}[/itex] = q*l => 40 * 280 = 11200 N/cm, 112 N/m, 0,112 kN/m

And assuming that the above is correct, which I do not know, I can go ahead and find F[itex]_{A}[/itex] and F[itex]_{B}[/itex]
The numbers are right, but not the units. If you multiply N/cm by cm what do you get?
 
  • #3
haruspex said:
The numbers are right, but not the units. If you multiply N/cm by cm what do you get?

Just N?
 
  • #4
Antex said:
Just N?
Yes.
 
  • #5
haruspex said:
Yes.

Could you explain me the difference if there was no overhang at A, and the UDL ended at A? Is there a different process in calculation in that case?

And also: 11200 N is then 112 kN? or would it be N/m and then 1.12 kN?
 
  • #6
1. The difference is in the position where Fq "grabs". Otherwise same calculation.
2. No: 11200 N = 11200 N / (1000 N/kN)
or if you are word-oriented: eleven thousand 200 = eleven thousand plus (200 * thousand/thousand) = (eleven plus 200/thousand ) * thousand​
 
  • #7
Antex said:
Could you explain me the difference if there was no overhang at A, and the UDL ended at A? Is there a different process in calculation in that case?

And also: 11200 N is then 112 kN? or would it be N/m and then 1.12 kN?
When determining the support reactions, the UDL can be represented by a single concentrated load of 11,200 N acting at the center of gravity of UDL, that is, at (a + l)/2 from the left end of the beam.
 

1. What is beam bending moment?

Beam bending moment is a measurement of the internal force that causes a beam to bend or deform. It is the result of external loads acting on the beam, such as weight or pressure, and is typically represented by the symbol "M".

2. How is beam bending moment calculated?

Beam bending moment can be calculated using the equation M = Fd, where "F" is the external force acting on the beam and "d" is the distance from the point of interest to the force.

3. What are the units of beam bending moment?

Beam bending moment is typically measured in units of force multiplied by distance, such as pound-feet (lb-ft) or newton-meters (N-m).

4. How does beam shape affect bending moment?

The shape of a beam can greatly affect the bending moment it experiences. Beams with a larger cross-sectional area are able to resist bending moments better than beams with a smaller cross-sectional area. Additionally, beams with more support, such as a solid rectangular beam compared to a hollow rectangular beam, will experience lower bending moments.

5. What are the practical applications of understanding beam bending moment?

Understanding beam bending moment is crucial in structural engineering and construction. It allows engineers to design beams that can safely support the loads they will experience, ensuring the structural integrity and safety of buildings, bridges, and other structures. It is also important in the design of machines and mechanical systems, where beams may experience bending moments from various forces and loads.

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