Cohesive behaviour relative displacement

[DJStatics]

Hi there

I have two questions related to surface-to-surface contact with cohesive behaviour:

1. How do I access CSLIP and COPEN field outputs using scripting? The following gives me a keyword error for CSLIP and COPEN using fieldOutputs[]:

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CSLIP_values = Frame.fieldOutputs['CSLIP'].getSubset(region=odb.rootAssembly.instances['instance_name']).values

2. Is there a field output which gives the relative displacement of elements on opposing surfaces in the cohesive behaviour contact function in the tangential and normal directions, regardless of whether the surfaces stay in contact or not. As I understand, CSLIP only gives the tangential relative displacement for surfaces in contact, but I would like to know the relative tangential displacement even if the surfaces are seperating.

Thanks!

 

[FEA way]

The getSubset(region=...) object expects the OdbSet object as a region.

There's no such output variable, you would have to calculate it based on the displacements of nodes on the opposing surfaces.

 

[DJStatics]

Hi FEA way

Thanks for replying.

1. I do think an instance can be a region for getSubset() (I am successfully using it to extract other results from an instance). Nevertheless, I noticed now that in my input file CSLIP and COPEN is not requested under *Contact Output, even though I can view CSLIP and COPEN in the GUI after opening the ODB. I will try to add it to the input file and then see if I can access it using scripting.

2. Ok

 

[FEA way]

CSLIP is indirectly requested as CDISP - it contains both COPEN and CSLIP. Does the error message point to this specific line of your script ?

 

[DJStatics]

I have realised one more thing regarding my second question. I think I have used the wrong words. I said I want to find the relative displacement when the surfaces in the contact pair are 'not in contact' or have 'separated'. However, I meant to say this considering the cohesive bond has not failed.

Does this mean that CSLIP and COPEN are the values I am looking for? Even if there is relative displacement between the surfaces and they are not physically in contact, CLSIP and COPEN is still valid because the bond has not failed?

 

[DJStatics]

It does point to the line containing Frame.fieldOutputs[].

If I use Frame.fieldOutputs['CDISP'] I get 'KeyError: CDISP'