deal.ii users, I'm learning deal.ii with the goal of using it to non-linear solid mechanics problems. In many of these problems (such as Step-44), a time step is used to move a calculation from the initial condition to the final loaded state.
Step-44 uses a uniform time-step, but there are instances where an adaptive time step would be helpful. Using the initial parameter settings in 2-D, I found that a time-step of 0.7 was too large (the residual was on the order of 10^3) for the calculation to converge. I modified Step-44 to allow the time increment to increase the time increment when the number of Newton-Raphson iterations for two consecutive increments is small enough. I used global variables to make this happen. I am, however, at a loss for how to efficiently make it so that Step-44 (or any other script) will automatically decrease a time-step. The only idea I had at the moment was to use a ``for'' loop and run a certain number of iterations, and each time the solution did not converge would be to multiply the time-step by some fraction. However, I am not sure this solution would work well with my previous solution Has anyone done this before, or have thoughts on how one might modify Step-44 to automatically increase and decrease based on the number of iterations required for Newton-Raphson convergence or divergence? Thank you for your help. James -- The deal.II project is located at http://www.dealii.org/ For mailing list/forum options, see https://groups.google.com/d/forum/dealii?hl=en --- You received this message because you are subscribed to the Google Groups "deal.II User Group" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/dealii/e0ec0522-510f-475c-bb9a-a615bd9b0800n%40googlegroups.com.
