Learning Forum

[ranma]

Hi,

is it possible to delete some elements from a mesh at a certain substep of solution and then make the analysis continue?

I tried using restart, but it doesn't work because the mesh changed.

[peteroznewman]

Yes, there is a feature called Element Birth and Death that you can read about in the ANSYS Help system, but you have to put that in the model at the beginning. You can Deactivate Boundary Conditions like Displacements by Time Step. You can also Deactivate Contacts by Time Step. But again, these are done in a controlled way by Time Step and can't just be added to a restart if they were not defined at the beginning of the model.

One thing I know you can do at a restart is change the magnitude of a force or displacement before restarting, and change Analysis Settings like Substeps.

[ranma]

Hi

thank you for your quick reply

but i tried with birth and death and it didn't help me. in fact the problem with my model is that some elements are getting distorted, so i was thinking of deactivating those to continue the analysis, but i keep getting the error for killed elements, can you please give me some advice to finish my analysis?

[peteroznewman]

Here is a long list of discussions found by searching on Google for ansys highly distorted elements.

Read some of those discussions and blogs and reply using the Insert Image button to show your overall model and where the distorted elements are.

The first thing to try is reducing the Time Step size by using more Substeps.

[ranma]

this is the image of the distorted elements:

and i also attach the x component of stress

i'm modelling a reinforced concrete beam under bending load using microplane and I saw that the convergence issue always happen when some elements reach a certain tension stress, I had already tried with more than 1000 substeps, but the results never change, and the error happens for a displacement of 1,5mm.

[peteroznewman]

Are you loading the beam with a force or a displacement?

[ranma]

I'm loading with a displacement, because my objective is to calculate a load-displacement curve.