Bnding Moment diagram with one/two support/s?

[a5hl3yi]

I have drawn a beam that I have made up that has two supports on it but only one is in contact with the beam. how would I go about drawing a BM diagram for this beam? The BM diagram has to show the values at (from left to right) the first support, the first dotted line, the second support and the second dotted line.

Any help apreciated

Thnx

Ash

 

[Studiot]

Your beam is called a see-saw.

Try forgetting the disconnected support and inverting the beam, so the loads and supports are interchanged.

Does this help?

 

[a5hl3yi]

yea thanx. Ill use this to give it a go. Ill let u know if I crack it and mabe post what I get as my answer up. Hopefuly tho ill of done it correct :D

At least I know what it is now, never done anythin like this one befor. Thnx for the help.

 

[pongo38]

The bending moment diagram is a graph showing the variation of bending moment along the beam. To draw it, you could calculate the bending moment at different sections of the beam, and then plotting their values, using the beam itself as a base line. One definition of the bm at a section is: the algebraic sum of the moments on one side of that section. As there are two sides to every section, you will have an automatic check on the bending moment at that section. We can call these ML and MR. They should be exactly the same if everything is in order and sign conventions applied correctly. In your case, you will go round and round, unable to get ML to be the same as MR. Why is that? Because, until you connect the beam with its second support, you have a mechanism, for which the BM diagram is a bit pointless.

 

[DeeNos]

I would suggest starting by identifying the type of supports present on the beam. Based on your description, it seems like the beam has a fixed support at one end and a roller support at the other end. This means that the fixed support can resist both vertical and horizontal forces, while the roller support can only resist vertical forces.

Next, I would recommend determining the reactions at each support. This can be done by using the equations of equilibrium and considering the external loads applied to the beam. Once you have the reactions, you can plot them on the BM diagram.

To draw the BM diagram, you will need to consider the different sections of the beam between the supports. At each section, you will need to calculate the bending moment by considering the external loads and reactions acting on that section. This will give you a series of values that can be plotted on the BM diagram.

Starting from the left support, plot the bending moment value at that point. Then, move to the first dotted line and plot the bending moment value at that point. Continue this process until you reach the right support and the second dotted line.

It is important to note that the bending moment at the supports will be zero since they are fixed and roller supports. The maximum bending moment value will occur at the point of maximum deflection, which can be found by setting the slope of the BM diagram to zero and solving for the corresponding point.

In conclusion, drawing a BM diagram for a beam with one fixed support and one roller support involves identifying the type of supports, determining the reactions, and calculating the bending moment at different sections of the beam. By following these steps, you should be able to accurately plot the BM diagram for your beam.