Problems with loading conditions

[roldy]

I am trying to do a structural study on a u-channel. I modeled half of the u-channel in Abaqus to utilize its symmetry. I have a load of 97.961025 N spread over an area of 0.002852 m² but since I am using a symmetric model I use half the area to calculate the pressure load. The pressure load I am using is 17174.09274 Pa. I created a surface set for this pressure load. I created a set for the fixed faces which lie on top of a support structure and a set for the symmetry. The material I am using is aluminum. When I run the simulation, I do not get expected results. I set the deflection scale to 1 to see how much of an error I had. Hand calculations suggest that the deflection should be around 0.00026 m (0.26 mm). I am now wondering if I am using the pressure load incorrectly or perhaps a wrong value. I attached a zip file of pictures to show some steps. Any help would be greatly appreciated.

 

[Mustaine3]

Pressure is a force per area. So it's independent of the area.
Take the full force and divide it by the full area. Or take half of the force and divide it by half of the area - the result is the same.

 

[roldy]

I corrected the pressure value. This however will not change the results. Just for kicks, I suppressed the pressure load and applied a concentrated force of 97.961025 N at the center of the area for the pressure load (I know this is incorrect). I still get a very large deflection. I am using 69 GPa for Young's Modulus. I can't figure out what's wrong. Attached is the .cae file.

 

[Mustaine3]

In the attached file your material data are different. Check that again.
Try also C3D8I or C3D20R elements. Maybe you have Hourglassing with your current mesh.

Depending on the overall deflection, you should also check if the solution becomes nonlinear, so you have to activate NLGEOM.

 

[roldy]

I redid everything after model creation. I got it to work this time. Hand calculations were 0.258 mm and simulation results are 0.257. I am happy.