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Contact Interaction

Contact Interaction

Contact Interaction

(OP)
I'm trying to model two blocks sitting on top of each other (learning before I use it on the real model) and want to establish an interaction so when one block displaces into the other, it makes contact it makes the second displace and form stresses.  But when I try to move the first block away from the second, the program won't run, it comes up with an error.  How can I model it so when it displaces into the block, the second block forms stresses but when it displaces away, a gap is created?

RE: Contact Interaction

(OP)
Thanks for the file, it helped out some.  I can get my model to separate if my young's modulus is less than 1,000,000 psi, but I'm using concrete and mine is around 3,600,000.  I changed my interaction properties to be the same as that file but it won't run with my young's modulus value.   Any idea why?

RE: Contact Interaction

What is the error mesaage that you get?

Regards

Martin Stokes CEng MIMechE

RE: Contact Interaction

(OP)
I get too many attempts to on this increment error.  I noticed if I don't include a plastic response, then I'm fine, but if I include a plastic response (concrete damage plasticity) then it'll give me that error as soon as the model tries to displace.

RE: Contact Interaction

One thing to check.  Have you fully constrained the translations of the blocks?  If there are any free degrees of freedom, you will get rigid body motions which could well cause the analysis to fail.

Regards

Martin Stokes CEng MIMechE

RE: Contact Interaction

I've found the same thing with 6.7.1, that the file won't open without a jnl file. I'm almost certain that earlier versions of CAE will open a file without a jnl file and only a warning is given. Try it with 6.6 or 6.5 if you have them available.

With contact problems I've found that even slight changes to the model can mean success or failure. As the OP managed a solution without plasticity then the restraints being applied are correct and there is no rigid body motion.

The choice of master and slave surfaces can have an effect on the solution and the advice is that the master surface should be the harder surface. If the mesh between the two are dissimilar then choose the master surface to be the coarser mesh. If you're not sure then it's sometimes worth just switching the master/slave surfaces around to see if it will work. In the same way a contact analysis can be made to work if you modify the mesh slightly. The problem can lie with a single node that won't converge. Using the automatic tolerances option in contact controls can often make an analysis work too.

corus

RE: Contact Interaction

Lack of a jnl will not affect the ability to open a cae database.

There's something else wrong with the block.cae file (perhaps it did not download cleanly from that file sharing site?)

RE: Contact Interaction

I have no idea what happened to the CAE file.  I think it got corrupted on my end.  The INP should be sufficient though.  Sorry about that.

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