creep convergence issue

- February 22, 2024 at 10:52 am
  
  BALAMUGESH M
  Subscriber
  
  hi all,
  i need to know, if i put constants from th APDL to Creep model and simulate, there is conergence issue at the begining of the creep stage on, what will be the problem what i need to focus to avoid this convergenc issue
- February 22, 2024 at 11:09 am
  
  peteroznewman
  Subscriber
  
  One thing to focus on is to use sufficiently small time steps at the beginning of the simulation.
- February 22, 2024 at 11:13 am
  
  BALAMUGESH M
  Subscriber
  
  i have used only two time steps sub steps like 100, 100, 1000. it is not converging failure at the begning itself
- February 22, 2024 at 10:43 pm
  
  peteroznewman
  Subscriber
  
  What is your end time? Let's say it is 65,536 seconds. That is 4^8.
  Use 8 steps with end times of 4, 16, 64, 256, 1024, 4,096, 16,384, 65536.
  I expect if Step 1 has an end time of 4 seconds and you give it 100 initial substeps, it will converge. If it does not, there is something wrong with your model.
- February 23, 2024 at 5:40 am
  
  BALAMUGESH M
  Subscriber
  
  thanks for your message,
  i choosen modified time hardening model,if i apply this constants results are not converging, but if i reduce C1 1/7 then it runs completely but the expt and Fea strain results are not matching.
  
  is there any way to do tertiary creep by user defined program(V22 R1)?