Beams and bending
Beams and bending
(OP)
I have been trying to work out some reaction forces and bending momnets. Not too difficult normally but I seem to have hit a stumbling block. My problem is that the beam has 2 UDL's I spans the whole beam but the other just a small section, Im having troube working things out, could anyone point me in the right direction.
Beam sketch attached
Beam sketch attached





RE: Beams and bending
RE: Beams and bending
RE: Beams and bending
RE: Beams and bending
I'll give you the benefit of the doubt.
Moments about Ra first, then moments about Rb. Reation is just total load acting on beam, you just need to work out the proportion...how much act at Ra and how much at Rb and remember that UDL load is always taken at the centre of the UDL.
You are more likely to remember it if you do it yourself.
Adrian
RE: Beams and bending
you can then determine the moment in the beam by method of cuts, bfore the udl, at its middle, at the far end.
else you can use roark.
RE: Beams and bending
RE: Beams and bending
You can also use the pointy, conditional brackets, to construct your bending equations. It really helps if you did not throw away your old textbooks after college.
RE: Beams and bending
RE: Beams and bending
The most elementary and informative way of doing it is to solve for the right reaction by summing the moments about the left support. Then the left reaction is just the difference between the total load and the right reaction. Draw a shear diagram. With the shear diagram, the points of zero shear locate the points of maximumn moment. The areas under the shear diagram are the changes in moment.