Mullins damage variable

- May 1, 2019 at 4:11 pm
  
  omkar5990
  Subscriber
  
  Hello all,
  
  I am trying to evaluate the mullins damage variable over time in a soft tissue. I have created a new material using Mooney-Rivlin parameters and have introduced stress-softening using Mullins effect. My geometry is a simple rectangular shaped plate. One end of which is fixed and the other end is subjected to a time varying cyclic force. I have specified this force as a function of time in the loading conditions.
  
  When I run the simulation, I get an unconverged solution and couple of warnings. I also ran the simulation with just a constant ramped force of 1N and it worked fine.
  
  These are the warnings and the errors
  
  "Solver pivot warnings or errors have been encountered during the solution. This is usually a result of an ill conditioned matrix possibly due to unreasonable material properties, an under constrained model, or contact related issues. Check results carefully."
  
  "Element 6269 located in Body "Solid" (and maybe other elements) has become highly distorted. You may select the offending object and/or geometry via RMB on this warning in the Messages window. Excessive distortion of elements is usually a symptom indicating the need for corrective action elsewhere. Try incrementing the load more slowly (increase the number of substeps or decrease the time step size). You may need to improve your mesh to obtain elements with better aspect ratios. Also consider the behavior of materials, contact pairs, and/or constraint equations. If this message appears in the first iteration of first substep, be sure to perform element shape checking. Named Selections for the offending element can be created via the Identify Element Violations property on the Solution Information Object."
  
  "The unconverged solution (identified as Substep 999999) is output for analysis debug purposes. Results at this time should not be used for any other purpose."
  
  "The solver engine was unable to converge on a solution for the nonlinear problem as constrained. Please see the Troubleshooting section of the Help System for more information."
  
  This is the first time I am using a non-linear material and I am not very sure how troubleshoot this problem. Any help would be great! thanks!