Simply Supported Beam Safe load

[nvn]

rad10k: You obtained the same answer because you used your previous applied load to compute the deflection. Then you used that deflection to again compute the applied load. Perhaps talk to your tutor.

 

[pongo38]

Pongo38 : Well for instance the formula in post 20 : w = 4M/e. That was originally in my textbook as a formula for maximum bending moment : M = we/4 for a simply supported beam with point load in the middle but had been swapped around to solve to be used to solve W. I don't understand why the 4 was moved to be multiplied by M and then divided by e ?? Hope this ellaborates more on what I mean s

w = 4M/e is an equation where the left hand side is equal to the right hand side. If you divide both sides of the equation by 4, then the equality should hold. So, w/4 = M/e because 4/4 is the same as 1.
Then if you multiply both sides of the equation by e, then the equality still holds. So, we/4 = M.
Does that cover the point you are making?
Incidentally it is conventional to distinguish between upper case W and lower case w. So you should be careful to use the same symbol throughout.

 

[rad10k]

thanks pongo38 that helps.

nvn : I spoke to my tutor and explained that I was getting the same answer using the formula in post 23. Apparently I am solving ObZ/k = M incorrectly and should be using EL = M
then using the formula in post 23.

E = 204 000

 

[john thompson]

hi i am have the same problems with this quetion you mentioned that your tutor said use EL= M i asume that E is modules of elastcity in N/mm2 and i assume L is length of beam in mms and you also say that the formula is post 23 but i cannot work out which formula you used any help and i would be very greatfull