How to Calculate Midspan Deflection of a Cantilever Beam with Uniform Load?

[raymanmusic]

Homework Statement

How do I find an expression for the deflection at midspan for a cantilever beam loaded with a uniformly distributed load?

Illustration of beam: http://goo.gl/3SxeVZ

Homework Equations

$\delta = \frac{Qx^2}{24EI}(6L^2-4Lx+x^2)$

The Attempt at a Solution

Attempt at solution: http://goo.gl/umUBkU

My current answer is: $\frac{49QL^4}{1280EI}$, I think this is wrong. Putting $x = \frac{L}{2}$ in the elastic curve formula I get: $\frac{17QL^4}{384EI}$, I think this is the correct answer.

 

[SteamKing]

You can always check your formula for the deflection by setting x = L and seeing if your result is the same as that from a beam table.

 

[nvn]

raymanmusic: qx = q, not qx = q*x/L. Try again.

 

[raymanmusic]

Yes, that was the mistake. I got the correct answer now: $\frac{17QL^4}{384EI}$. Thank you nvn.