Re: [deal.II] Trying to run 2d simulation in step 18

[Wolfgang Bangerth]

On 3/8/23 14:29, Abhishek Nath Thakur wrote:
>
> Why at every time steps i am getting norm of rhs is 0 and why it is converged
> at 0 iteration?
> i tried to find the error by myself and i got that  gradient of variable is
> zero and incremental distance is also coming zero at every time step..

I can only speculate, not having the code. The usual reason for this is
because you are solving a problem with no external forcing (no body forces, no
boundary tractions, no non-zero Dirichlet boundary values). You can easily
check this: If the right hand side vector of the linear system you are solving
is zero, then there are no external forces. As a consequence, the
displacements are also zero, and the solution of the linear system happens
before the iterations even start.

Why that is so is something you need to debug. For example: Do the
if-conditions ever trigger to set any part of the boundary to specific
boundary_ids? Do you actually call VectorTools::interpolate_boundary_values()
on specific boundaries? Do you think you have a body force but it is not
applied? Etc.

Best
W.

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Wolfgang Bangerth email: bang...@colostate.edu
www: http://www.math.colostate.edu/~bangerth/