Learning Forum

[daniel.pascual]

Hello all I am currently involve on my Master's thesis on which I am trying to simulate a linear peristaltic pump mechanism using Transient Mechanical. I use the ANSYS 2020 R1 version given by the University.
The system is formed by 12 rigid actuators which displace perpendicular over a silicon rubber line, that means that it is an hyperelastic material with large deflection.
The problem that I am having is that after around 30% of simulation I get an error message regarding the excessive mesh elements distortion.
Some setup options that I changed until this time:
Contacts:
Rough contacts with asymmetric behaviour. Interface tratment between the actuator surface and the line "Add offset, Ramped effects"
Normal Stiffness 0.3, which can help the simulation to converge. However I get an excesive elements penetration on the silicon line before the error message appears.
Mesh: 5 hex. elements through the line wall thickness. Nonlinear Mechanical and linear order.
Mixed u-P formulation.
Step end time 2.636 s. Min. time step 0.001 s, Max. time step 0.003 s.
I am looking for some help to overcome this problem.
Thank you in advance.

[Akshay Maniyar]

Can you check the Ansys how to video which explains various ways to handle element distortion issues?
Also, make sure that the softer material is the contact side.
Thanks Amaniyar

[daniel.pascual]

First of all thank you for your response.
However I watched that video some time ago and I could carry out some of the tips given except the nonlinear mesh adaptivity which cannot be applied on my model.
The contacts and targets are perfectly given. I could have doubts regarding the interface treatment and other options such as the contact formulation between the actuators and the silicon line. I don't know if my problem could be related with it.
Finally I want to ask if a much more finer mesh than which the one I applied could be a good viable option.
Once again thank you.

[Akshay Maniyar]

As there will be some sliding, but with rough contacts, sliding is not possible. Can you try to use frictional contact with high coefficient of friction and see if it helps? Also, turn off the small sliding option under contacts settings. Also, you can try to change the detection method to 'Nodal-project normal from contact' and see if it helps.

Thanks Amaniyar