A simply supported beam has 2 equal point loads (W/2)

[SarahM1980]

I have a simply supported beam 1.2m long
it has 2 = point loads (W/2) at equal distances (0.4m) along the beam
i have been asked to derive from first principles the expression for the mid span defelction.
I have got so far m= W/2x - W/2(x-L3) - W/2(x-L/6)
and i think the answer I'm looking for is something like 23WL 3 / 1296EI


can anyone help!

 

[radou]

You can either use the equation w''(x) = M(x) / EI , or a dummy force method (which I personally prefer more).