Question:
I know how to calculate stress and deflection on simple beam cross
sections but I'm not sure how to do this...
Suppose you have a hydraulic cylinder pushing against a round plate that
has an evenly distributed load on the other side, how do you figure the
stress in a plate of a given thickness and diameter. If the calculation
for having the load at the outer edges of the round plate is easier that
would probably get me close enough.
the example I am wanting to work on now is a 12" diameter plate with a
60,000 lbs force from a 2" diameter hydraulic cylinder rod pushing on
the center. I want to know how thick the plate needs to be to keep the
stress to about 15,000 psi and also how much the plate will deflect.
Answer:
The simplest way would be to use a finite element analysis tool. The
problem is that you do not have a constant value for your moment of inertia.
I have the 4th edition of Roark's. In Table X - Formulas for Flat Plates, Case number 3 looks like
your answer. You need the modulus elasticity and Poisson's ratio (reciprocal) for the material of
your 12" dia. plate. The rest is plug and play on a pocket calculator. I assume the 2" cylinder
rod has a flat end which will create a circular ring load condition as it deflects the plate
Sorry I should have included that bit of information in my first post.
I will be using A36 steel, I have never used Poisson's ratio before so I
don't know what it is for steel. As for the 2" cylinder rod, it is
actually threaded on the end so I will probably take some 3 or 4" round
and tap the inside and screw the it onto the rod after it is welded to
the 12" diameter plate. That way the load will be spread out a little
and keep the stress down. Do you mind posting the formula for that BTW?
