Contact gap visualization

[gcassianno]

Hi,

I'm trying to plot the gap between two surfaces, similar to what the Contact Tool does in ANSYS Workbench. I've tried a few different approaches, but nothing worked. I saw in the documentation that PRESOL could be used, but the GAP command isn't recognized, even when I try using mapdl.post_processing.

How can I visualize the contact gap between surfaces in MAPDL? Any examples would be really helpful.

Thanks in advance!

[mikerife]

@gcassianno can you please show that the gap result is not being post processed? For example in a model that uses contact174 elements, and assuming that I did not limit the result output, then the following will plot the contact gap:

mapdl.post1()
mapdl.set('last')
mapdl.esel('s', 'ename', '', 174)    # or use 172 for 2D contact element type
mapdl.nsle('s')
mapdl.post_processing.plot_element_values('cont', 'gap')

mike

[mikerife]

@gcassianno You are not showing all the commands...mapdl.file() just points to the result file. Did you read in a set of results with set? Are you sure that the contact results were written to the rst file?

[gcassianno]

I'm not sure if the contact results were written to the .rst file, I thought this was done automatically.

So, before running the simulation, which command do I need to execute to ensure this?

Below are all the commands I'm currently running:

`
mapdl.clear()
mapdl.resume(db_file_path,'db',0,1)
mapdl.file(rst_file_path,'rst')
mapdl.post1()
mapdl.set('last')

mapdl.post1()
mapdl.set('last')
mapdl.esel('s', 'ename', '', 174) # or use 172 for 2D contact element type
mapdl.nsle('s')
mapdl.post_processing.plot_element_values('cont', 'gap')

`

After that, I get the following error:

Label __ETABLE not recognized.

[mikerife]

Hi @gcassianno by default almost all result types are saved to the result file. One feature that PyDPF and PyMAPDL Reader have that PyMAPDL does not (hint @germa89) is a way to show which results are available in a result file. Try this:

from ansys.mapdl import reader as pymapdl_reader
rst = pymapdl_reader.read_binary('file.rst')
print(rst)

Does it give something like this:

Is ECT listed? If so can you share the rst? Or maybe a different contact element type was used (and not 174)?
Mike

[gcassianno]

There is no ECT listed in the .rst file.

Here's what is shown when reading the file as you mentioned:

Available Results:
EMS : Miscellaneous summable items (normally includes face pressures)
ENF : Nodal forces
ENS : Nodal stresses
ENG : Element energies and volume
EEL : Nodal elastic strains
ETH : Nodal thermal strains (includes swelling strains)
EUL : Element euler angles
EPT : Nodal temperatures
NSL : Nodal displacements
RF : Nodal reaction forces

However, I used element 174 for the contact.

[mikerife]

@gcassianno can you share the rst file? Maybe there is no contact happening in the model so there are no contact results?