Strengths Help

1. Mar 12, 2006

EQ

Cant upload the right pic but kinda got a diagram up.

Last edited: Mar 12, 2006
2. Mar 12, 2006

EQ

I need help finding reactions for a fixed cantilever. total length is 16ft and its fixed on the right side. The loads on it going from left to right. 2000 lbs at the end of the left. 1000 lbs 10ft from left. There is one support for the cantilever and its where A is at which is 6 ft from left. The dimension for the 1000 lb load is 6ft from B which is the fixed point of the cantilever.

I've been summing the moments at A and B and my numbers are 3800 at A and 800 at B with a zero torque moment at B which is not right, it has to have a torque moment.

2000......10ft......1000.....6ft...
|
|_______________|_________ B Fixed End
......6ft.... A ..............10ft....

Thanks

Last edited: Mar 12, 2006
3. Mar 12, 2006

haynewp

If "A" is a roller and has one reaction, and "B" is fixed for 2 translations and 1 rotation, then that is an indeterminate problem. You will need additional beam properties to be able to solve it.

4. Mar 12, 2006

Cyrus

Don't double post, cyclovenom already gave you a response.

5. Mar 12, 2006

EQ

For the rotation at B it should just be the sum of the moments correct?

After getting the reactions. I would be able to get a V max and M max from diagrams.

6. Mar 12, 2006

Cyrus

You need to post a real picture. Thats a joke, sorry.

7. Mar 12, 2006

haynewp

There are a couple of ways to solve an indeterminate beam problem. If you were not given the moment of inertia or modulus of elasticity, then the "flexibility" or "integration" method would be the one I would use to give you the approximate answers, since the E and I for this problem are likely to cancel out.

8. Mar 13, 2006

Pyrrhus

This is a hyperstatic system solved by differential equation of the deflexion curve. So what you should do is express reactionary moment in terms of the reaction at support A, and the reactionary force in B in terms of the reaction at support A, then start making your sections (bending moment equations).

If you want further help than that, Show your work.

9. Mar 13, 2006

haynewp

I believe that is the same as what I am calling the integration method:

Either way, the assumption has to be made that the shear deformation is negligible compared to flexural deformation, or else you would need additional beam properties to get the correct solution.

Last edited by a moderator: Mar 4, 2015
10. Mar 13, 2006

Pyrrhus

Yes haynewp, we are talking about the same method.

EQ, Check pages 15-19 of the PDF haynewp provided. There's a similar problem like yours

11. Mar 13, 2006

EQ

Thanks for the help guys. I figured my problem, I didn't get my reaction right at B its negative not positve which threw off my shear diagram.

For deflection I did moment by parts.