Ansys, reason for difference between calculated and ansys results

EEm

We had to calculate the stress concentration factor Kt for an element. we read the calculated values from the graph and calculated the stress on ansys. I know that plane stress models have a thickness of 0 and we used a thickness of 2mm so I presume this is a reason for error?

Also the pressure on the hole is acting over the whole line of top half of the hold where it should really be added onto the nodes, with less pressure the closer you get to the horizontal as the bolt would be pulling upwards

What other reasons for error are there?

Are there any assumptions in the formulas in the graphs?

Oh and the stress concentration formula for the ansys one we used was

Normal stress/Max stress (Or could have been flipped upside down).

This is the piece we did it on.

EEm

Anyone?

Turbulent Bill

ANSYS used to have a range of verification examples, where they'd take a range of classical problems like the hole-in-plate above, show the ANSYS solution and compare it to the analytical/empirical results from a book. This should be your first place to start.

There'll always be a finite difference in the results, but it should be very, very small.

chris85

You must also look at the meshing of the model in Ansys. Is the mesh fine enough for the distribution of the stress. It would be good to do a convergence test for the mesh. This will help on this. Its also good practice to do so for most models. This is of particular importance around the hole of the plate.