Cannot Run Model with Hyperelasticity and CZM Enabled

Hello,

I am having a consistent error pop up when I try to run a DCB model for a hyperelastic material with separation distance-based debonding enabled. This model is currently in Static Structural. The error in the solution output is:

"More than one material option has been defined for material 1. Hyperelastic material (TB,HYPER) is not supported with other nonlinear models."

I've double checked my Engineering Data for the hyperelastic material and it doesn't seem like more than one material option has been defined (see below):

Furthermore, I know for sure that this setup worked in ANSYS 2019, but now that our school system is on 2020 I cannot get this model to work. The 2D model I am trying to run is shown below:

where there is a 0.5 mm displacement of the right-most edge. Both blocks are assigned to the same "Hyperelastic Material" option as defined in the initial screenshot.

As far as I'm aware, I don't think CZM is restricted to only linear elastic properties, as there have been other posts of hyperelasticity + CZM successfully modeled (ie: https://forum.ansys.com/discussion/comment/7014#Comment_7014) and, like I've said before, I was able to get this model to run successfully using ANSYS 2019 in the past, with a much more complex setup (where there is a needle at the top of the blocks undergoing a vertical displacement to split the two blocks apart).


In the gif video, the model is currently set up with hyperelasticity and separation distance-based debonding enabled. However, the last time this model was run was on ANSYS 2019, and when I rerun the model in 2020 the materials error appears!

Some additional parameters set for my model:

1) Connections - only a contact region of the shared interface between the blocks. Contact region is set to Bonded Contact with Pure Penalty formulation.

2) Fracture - added "Contact Debonding" with material set to "Hyperelastic Material" and Contact Region set to "Bonded Contact" as assigned above

Some additional troubleshooting I've tried:

1) Creating geometry in DesignModeler, SpaceClaim, and SolidWorks - same error

2) Running model in plane stress, then plane strain - same error

3) Refining mesh - same error

4) Setting hyperelasticity with CZM debonding via APDL - same error

5) Tried to download ANSYS 2019, but just learned that their licensing expired in August

Please let me know if any additional information should be provided. I greatly appreciate anyone who has some additional troubleshooting tips or any ideas in general on what I'm doing incorrectly here! :)

Best Answer

Answers

  • THANK YOU SO MUCH @bsista! I didn't realize that we now have to create two completely new materials (one as the "interface", one as the hyperelastic material) to get this to work. In 2019 both could be lumped together in one material, but I guess this new method can allow more flexibility in assigning interfacial properties separate from the geometric properties itself. Many thanks!!!

  • It should have been the same case in prior versions too. Theoretically, CZM cannot be assigned to continuum stress elements and hyperelastic material model cannot be assigned to interface (or contact) elements.

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