Issues with basic solidworks FEA

[DustinP770]

Hello all, My name is Dustin and I'm a mechanical engineering student trying to become more familiar with FEA and I'm having some issues with Solidwork Simulation of an example in my textbook. I have used the software before and have had success with it, but I'm struggling to get stress values to agree with my hand calculations (verified with my textbook) for a rectangular cross section crane hook simulation. My problem is stated as follows:

Crane hook with a rectangular cross section 0.75" x 4" (area of 3in^2), an inner radius of 2", and an outer radius of 6" has a 5000lb load applied at the center of the hook downward. According to my calculations, the maximum stress on the inside of the hook should be around 16.9ksi and minimum of -5.69ksi on the outside of the hook. I created a small area to distribute the 5000lb of force using split lines on the surface.

My simulation results are giving me around 17.9ksi on the inside and -5.9ksi on the outside. I understand that calculations are theoretical and the simulation is an estimation, but shouldn't the results be closer to eachother?

I have attached an image of my mesh, the contour plot for the stress, and the results obtained for multiple sensors on the cross section where the maximum stress occurs. Thank you in advance for any guidance provided.

 

[TheTick]

In this case, I would tend to believe the FEA. Also, keep refining the mesh until results converge. Auto-refinement is a big help for this.

 

[corus]

Even though the calculations are theoretical, they are still based upon some assumptions and as such are an estimate. The FE model is also an estimate but only based upon the refinement of the mesh (and assuming you know the loads and boundary conditions are correct). The calculations do give some confirmation of your FE model but on their own they are not the definitive answer.