Beam calculations

[paulpatrick]

Hi
first of can someone remind me how we calculate a beams deflection under its own weight? its beeen like 10years since I left college and had to do any calculations...
I have a large sheet of metal which has beams weilded in a grid fashion all over it and It got to be lifted and moved.
I have a limit on the number of lifting point i.e. four. I am considering using a section of the " uneven I beam" to do the cals as in use aguide. in the x and z direction in which the beams traverse. The beams in he z direction are bigger.. Any advice from the people in the know would be great.

 

[desertfox]

Hi paulpatrick

Have a look at this site it might help:-

http://www.roymech.co.uk/Useful_Tables/Beams/Beam_Index.html#Links

Also for self weight of beam it is considered to be a uniformly distributed load over the beam length.

desertfox

 

[steellion]

Figure out the beam's moment of inertia. If it is simply supported on each side, the equation for deflection is 5wL^4/384EI, where w is weight per unit length.

 

[rb1957]

"equation for deflection is 5wL^4/384EI" is right of a simply supported beam. for a beam with many supports, "the number of lifting point i.e. four", you need something like the three moment equation.