Learning Forum

[Hussam Khresat]

Hi all, 

I created a solid 3D model of a steel (E=2.9008e+07 psi) plate. See attached picture for dimesnions and boundary conditions; the dashed lines represent where the boundary conditions are applied. A force of 5000 lbs in the z direction (laterally) is applied at mid span as shown. 

I want to compare the static analysis solution from ansys vs solution by hand for maximum lateral displacement. The following are the results I got

Ansys solution: 0.012228 in

Hand solution: 0.009593 in

which shows about I am getting 13% difference and I am not sure why.

For hand solution I derived my answer from y''=M(x)/EI

I am not accounting shear strain as I assumed it would be negligible since my beam I considered to be thin is that a valid assumption?

Additional note: I tried different variations of the same setup by ONLY reducing the width of my plate (for example instead of 12in tried 6, and 4 in) and what I found is that as my beam width decreases my hand and ansys solutions match much better. I am also not sure why, any help will be greatly appreciated. 

 

[peteroznewman]

If you were bending about the 0.41 inch thickness direction, that would indeed be thin and you could ignore the shear deformation, but bending about the 12 inch direction is NOT thin and you can't ignore the shear deformation.