Trying to learn contact analysis using Femap SOL 101 solver and thus picked up some standardized test cases.
This particular problem involves performing a linear contact analysis between solid & shell elements.
The set up is shown below:
Contains solid elements blocks, the base which is fixed in all directions. The plate is suspended 0.05" above the solid block upper faces. The plate has a pressure load applied downwards so that they make contact with solid blocks. Certain nodes in the plate are constrained in X & Y directions to prevent rigid body motion. The blocks are of "Softer Materials" and plate is Aluminum 2024-T3.
The contact card is shown below. I've played with different settings. Plugging in a small value for friction (0.05 to 0.1), varying Max search distance (0.055 to 0.1), running with include shell & not include shell thickness options, setting initial gap/penetration to 0 etc.
Have created 3 contact regions. Left Solid upper face, right solid upper face and shell. I've made sure that shell elements bottom elements are the ones in contact.
But when I run the analysis, I get the following deformation pattern:
There is some penetration of the solid by the shell.
And finally an output vector called Contact Pressures is presented. So if I want to find out total stresses for the elements circled in the image below, then do I need to add contact stress values to an additional output vector like Von Mises? Or does Von Mises output vector already factor in stresses due to contact?
Would appreciate some insights.
I guess that the penetration you are seeing is due the scale you used for the plot. put scale deformation 1 and check contact gap/penetartion to check the real value. If the penetarion is large you can play with the autopenalty or penalty factor. check if the resulrs change a lot.
About stresses you do not have to add pressure to Von Mises.
Anyway looking the model I guess you will have singularity due to edge contact to read stresses there
Here you are a few suggestions:
I never really thought about deformation scale or resolution. A small but important detail, eh? Duh!
Jon_Morga, if I understood your reply correctly, it seems like Von Mises output contains contact pressure as well? If yes, then what is the use of contact pressure output?
The last question may seem obvious but I would like to know.
I will try to explain it
The contact pressure is the value in the direction of the normal establishes between surfaces. Von mises is calculated from stress tensor caused by this pressure.They are two different things.
I hope the explanation is enough
Regarding Point #2, what does it mean for Post-processing? Do I have to use an interaction equation to factor the presence of both in plane & normal stress vectors?
What are the best practices regarding the above?