CATIA Generative Structural Analysis Stress Values

[lildaveyboy]

Hello. I have run some models in CATIA and I am getting stress values that are slightly lower than expected. I am getting about 3.8 ksi for the stress at an open hole and the value should be about 4.7 ksi based on the geometry and loading conditions. I confirmed this in ABAQUS and Peteron. I am wondering if anyone might have any idea as to what is causing this low stress value. Thanks.

 

[ESPcomposites]

How about giving the geometry and boundary conditions? Try to give as much relevant information as possible (without over doing it).

Based on the "look" of the fringe plot, discretization (too coarse of a mesh) could be your problem. Is the solver and h-element or p-element? Can you change to higher order elements if it is an h-element solver. If it is a p-element solver, make sure your convergence controls are set appropriately.

Please specify the type of solver, mesh density (perhaps via plot), element type/order.



Brian

http://www.espcomposites.com

 

[lildaveyboy]

Thanks. I did some reference and I think it is related to the mesh size. I belive the mesh is too coarse. I'm using 10-node parabolic tet elements. I'll try to make the mesh finer and see if that gets me closer to the correct value.

 

[AtlanticCoast]

If mesh density is an issue with tet elements, CATIA has a utility called "adaptivity" which will iterate your mesh. You can use global adaptivity to set error objectives, and local adaptivity to apply local areas such as box groups. This saves you the trouble of manually iterating.

The icon looks like a magnifying glass with a stress contour on it. Once you set up the global adaptivity objectives, you can set local ones by right clicking on the adaptivity in the tree. "Compute with adaptivity" is hidden under the compute button. Other options like min mesh size can be set once you click it.


John

http://www.AtlanticCoastAerospace.com