Cantilever beam.

  • Thread starter Thread starter NMC
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NMC

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Hi all,

I need to calculate a point load on the above type of beam.
Its overall length is 2.3m, load is applied at 0.500m with a force of 43.0N

How can I calculate/formula the reaction force? and reaction moment?

Thank you for your help.
Cantilever.gif
 
Hey NMC, if you're asking for homework help, it's best to mention that.
People are less willing to do school work help, in general, because if we spoon-feed it to you, it doesn't serve a purpose. If you're upfront, at least, you at least have some hope of getting help.

In this case, I'll just review the rules of thumb:
1. You can take moment around any point. In equilibrium, the sum (and sum around any axis) will be 0. Sum of forces (and forces in each axis) will also be 0.
2. Moment is Force*(perpendicular) distance from whatever point you use.
3. Don't forget about the weight of the beam.

4. Finally, the key here, is that the rule of thumb is to take the moment where you have the most unknown forces. That's because at 0 distance, the moment from those forces will be 0 at that point, so you can ignore them.
Here, the reactions will take place where the beam is fixed to the wall. Take your sum of moments around that point, and this is a trivial problem.
 
There are calculators online on web where you can draw the beam, put the loads and find the reactions at the supports. They are easy to use.

I want to tell you this so that you can check your work, and if it is your homework you should do it right. You wont get any points if you do it without the formulation anyway so try to do it first and then check google to get the answers and compare.

All the best.
 
MSHOfficial said:
There are calculators online on web where you can draw the beam, put the loads and find the reactions at the supports. They are easy to use.

I want to tell you this so that you can check your work, and if it is your homework you should do it right. You wont get any points if you do it without the formulation anyway so try to do it first and then check google to get the answers and compare.

All the best.
Click to expand...

Thanks for your help, I have seen the calculators but your correct, I want to understand it and show my workings.
 
s.weinberg said:
Hey NMC, if you're asking for homework help, it's best to mention that.
People are less willing to do school work help, in general, because if we spoon-feed it to you, it doesn't serve a purpose. If you're upfront, at least, you at least have some hope of getting help.

In this case, I'll just review the rules of thumb:
1. You can take moment around any point. In equilibrium, the sum (and sum around any axis) will be 0. Sum of forces (and forces in each axis) will also be 0.
2. Moment is Force*(perpendicular) distance from whatever point you use.
3. Don't forget about the weight of the beam.

4. Finally, the key here, is that the rule of thumb is to take the moment where you have the most unknown forces. That's because at 0 distance, the moment from those forces will be 0 at that point, so you can ignore them.
Here, the reactions will take place where the beam is fixed to the wall. Take your sum of moments around that point, and this is a trivial problem.
Click to expand...

Thanks for your help Bill, this is not homework but a quiz as part of a structure analysis course. I want to understand the workings and have a clear formula to work with anyway, appreciate your feedback.
 
There is a bank of similar homework problems with detailed explanations here. I occasionally answer similar problems on that subbreddit. I would agree with what the other posters have said that it is the concepts that you need to understand and that simply giving you the answer isn't really helpful.

That being said, I will often offer help if you need it. Here or on another forum.
 
Thanks all for your feedback, I since resolved my work and a few lessons along the way. Much appreciated.
 
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