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Active Member
cheaneys
Posts: 6
Registered: ‎02-09-2014
Accepted Solution

Using General Contact Element

234 Views, 5 Replies
02-24-2014 01:44 PM

I am trying to figure out how to use the "General Contact" option under element type in autodesk simulation and I repeatedly get this one error (screen-shot attacted), despite trying to use the simplest model possible. Does anyone know why I am getting this error? I would greatly appreciate any help.

 

I have fixed the bottom face of the part in all 6 D.O.F. and constrained the other two faces for 5 D.O.F. (not constraining in the z translational direction). Applied a small force, inputted the rod's cross-setional area, along with values for coupling length, coupling modulus, and breaking stress.

 

My overall goal is to define an piece that will break after the part experiences a certain stress.

 

Any help will be appreciated, even just advice on how to get any part to work while using the general contact element option will be helpful.

 

Thank you,

 

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*Expert Elite*
AstroJohnPE
Posts: 529
Registered: ‎08-30-2012

Re: Using General Contact Element

02-24-2014 07:09 PM in reply to: cheaneys

I do not have my reading glasses on, so perhaps I am just overlooking it. But is there a screenshot attached that shows the error?

 

 

John Holtz, PE
Mechanical Engineer
Pittsburgh, PA

16.9 years experience with Simulation Mechanical
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Active Member
cheaneys
Posts: 6
Registered: ‎02-09-2014

Re: Using General Contact Element

02-24-2014 08:21 PM in reply to: AstroJohnPE

Sorry about that. Here is the attatched screenshot

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Active Member
cheaneys
Posts: 6
Registered: ‎02-09-2014

Re: Using General Contact Element

02-24-2014 08:23 PM in reply to: cheaneys

error2.PNG

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*Expert Elite*
AstroJohnPE
Posts: 529
Registered: ‎08-30-2012

Re: Using General Contact Element

02-25-2014 10:56 AM in reply to: cheaneys

 

That helps! :-)

 

The problem is that the software thinks that part 1 should be a solid, and it probably should be a solid! So the element type should be brick (if the rod is solid) or shell (if it is a hollow tube).

 

One general contact element is a line which you normally use to connect two parts of the model together, or connect the model to the ground. The line is an idealization of a real spring, similar to how a beam element (a straight line) represents the cross-section of a real beam. So if your model had worked, it would represent a net whose fibers or rope had the spring stiffness that you entered.

 

The software will not show the model break into pieces except perhaps in the most trivial situation. The usual method of determining if a part will break is by comparing the calculated stress to an allowable strength, such as the yield strength or ultimate tensile strength. Additionally, a fatigue analysis can be performed which would indicate if the part breaks due to cyclic loading.

 

John Holtz, PE
Mechanical Engineer
Pittsburgh, PA

16.9 years experience with Simulation Mechanical
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Active Member
cheaneys
Posts: 6
Registered: ‎02-09-2014

Re: Using General Contact Element

03-02-2014 09:24 PM in reply to: AstroJohnPE

Thank you for your help!

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