Note: This discussion is about an older version of the COMSOL Multiphysics® software. The information provided may be out of date.
Discussion Closed This discussion was created more than 6 months ago and has been closed. To start a new discussion with a link back to this one, click here.
very small time step
Posted Jun 19, 2012, 1:27 a.m. EDT Structural Mechanics Version 4.3 1 Reply
Please login with a confirmed email address before reporting spam
Hi,
I have hard time making my transient solution proceed faster (i.e. with bigger time step). For example although my time range is t=range(0, 1, 30) sec, and I force the initial time steps to be 0.01sec, the results proceed with very small increments of 0.00001sec. Can anyone advise how to make the time steps faster?
I am using structural mechanics with large deformation.
Thank you.
Jessica
I have hard time making my transient solution proceed faster (i.e. with bigger time step). For example although my time range is t=range(0, 1, 30) sec, and I force the initial time steps to be 0.01sec, the results proceed with very small increments of 0.00001sec. Can anyone advise how to make the time steps faster?
I am using structural mechanics with large deformation.
Thank you.
Jessica
1 Reply Last Post Jun 19, 2012, 3:13 a.m. EDT
Please login with a confirmed email address before reporting spam
Posted:
1 decade ago
Hi
if COMSOL uses small time steps its probably because the model starting point is such that the norm it uses for convergence is hardly changing. One way is to have a better initial condition, perhaps a stationary solver step first to get a more representative steady state situation could improve the time stepping thereafter (very model dependent) the other is to play with the solver time stepping, you could use a strict stepping with larger steps, but it might be that COMSOL does not manage to converge for the first one.
Often it starts very fine, then uses larger and larger steps
--
Good luck
Ivar
if COMSOL uses small time steps its probably because the model starting point is such that the norm it uses for convergence is hardly changing. One way is to have a better initial condition, perhaps a stationary solver step first to get a more representative steady state situation could improve the time stepping thereafter (very model dependent) the other is to play with the solver time stepping, you could use a strict stepping with larger steps, but it might be that COMSOL does not manage to converge for the first one.
Often it starts very fine, then uses larger and larger steps
--
Good luck
Ivar