Shear Forces and Bending Moments in Beams

In summary, the shear force is -200/π Sin(πx/8) and the bending moment is -400/π^2 Cos(πx/8) at each support.
  • #1
mit_hacker
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0

Homework Statement



(Q) A beam 4m long is supported at the left hand side by a hinge support and on the right by a roller support. It is under a non-uniform load intensity throughout by a load intensity given by:

w = 25Cos(pi x/8)kN/m.

Write equations for the shear force and the bending moments for any section of the beam.

Homework Equations



F= -∫▒w
M=-∫▒F

The Attempt at a Solution



I can easily apply the above formulas and integrate.

The shear force comes to -200/π Sin(πx/8).
Similarly, the Moments come to -400/π^2 Cos(πx/8)

But at the back of the book, there is also the constant term along with the term obtained by the integration.

Can someone please help me to calculate them. How did they come about?
 
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  • #2
mit_hacker said:

Homework Statement



(Q) A beam 4m long is supported at the left hand side by a hinge support and on the right by a roller support. It is under a non-uniform load intensity throughout by a load intensity given by:

w = 25Cos(pi x/8)kN/m.

Write equations for the shear force and the bending moments for any section of the beam.


Homework Equations



F= -∫▒w
M=-∫▒F


The Attempt at a Solution



I can easily apply the above formulas and integrate.

The shear force comes to -200/π Sin(πx/8).
Similarly, the Moments come to -400/π^2 Cos(πx/8)

But at the back of the book, there is also the constant term along with the term obtained by the integration.

Can someone please help me to calculate them. How did they come about?
You've got to look at the boundary conditions to get the constants. What do you know about the bending moment at each support?
 
  • #3
Ahhhhhhhhh!

That was so simple?:smile:

I can't believe that I didn't see it! Thanks a lot for your help PhantomJay!
 

FAQ: Shear Forces and Bending Moments in Beams

What is a shear force in a beam?

A shear force is a type of force that acts parallel to the surface of a beam, causing one part of the beam to slide past the other. In simpler terms, it is a force that causes a beam to bend or deform.

What is a bending moment in a beam?

A bending moment is a type of force that causes a beam to bend or twist. It is caused by external loads acting on a beam, such as weight or pressure.

How do shear forces and bending moments affect beams?

Shear forces and bending moments can cause beams to deform or break if they exceed the maximum capacity of the beam. They also determine the internal stresses and strains within the beam, which are important factors in designing and analyzing structures.

What is the difference between positive and negative bending moments?

Positive bending moments cause the top of a beam to compress and the bottom to stretch, while negative bending moments have the opposite effect. This is important in determining the maximum stress and deflection in a beam.

How can I calculate shear forces and bending moments in a beam?

Shear forces and bending moments can be calculated using equations and diagrams based on the type of load and support conditions of the beam. These calculations are commonly used in structural analysis and design to ensure the safety and stability of beams.

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