# Time step changing

I’m trying to change time step in preCICE / OpenFOAM and CalculiX but I’m find a error to simulate a case can you look for it please?

``````
iteration 1

Using up to 1 cpu(s) for the stress calculation.

Using up to 1 cpu(s) for the energy calculation.

Using up to 1 cpu(s) for the symmetric stiffness/mass contributions.

Factoring the system of equations using the symmetric spooles solver
Using up to 1 cpu(s) for spooles.

Using up to 1 cpu(s) for the stress calculation.

Using up to 1 cpu(s) for the energy calculation.

average force= 15469129.249106
time avg. forc= 1934082.949982
largest residual force= 0.000001 in node 39 and dof 1
largest increment of disp= 9.712185e+02
largest correction to disp= 9.712185e+02 in node 38 and dof 1

no convergence

iteration 2

Using up to 1 cpu(s) for the symmetric stiffness/mass contributions.

Factoring the system of equations using the symmetric spooles solver
Using up to 1 cpu(s) for spooles.

Using up to 1 cpu(s) for the stress calculation.

Using up to 1 cpu(s) for the energy calculation.

average force= 15469129.249106
time avg. forc= 1934082.949982
largest residual force= 0.000000 in node 51 and dof 1
largest increment of disp= 9.712185e+02
largest correction to disp= 7.011653e-11 in node 63 and dof 1

convergence

Writing DISPLACEMENTS coupling data with ID '2'.
---[precice]  relative convergence measure: relative two-norm diff of data "Displacement" = 2.63e-02, limit = 5.00e-02, normalization = 4.01e+03, conv = true
---[precice]  relative convergence measure: relative two-norm diff of data "Force" = 5.17e-01, limit = 5.00e-02, normalization = 2.09e+08, conv = false
---[precice] ERROR:  Send using sockets failed with system error: write: Broken pipe

``````

flap.inp (374 Bytes)
precice-config.xml (2.4 KB)

Hi,

You need to change the end time in the precice-config AND in the calculix .inp file. (Probably too with the openfoam case)
I think you forgot one of these

I have the same end time in all files; you can check files above.

You have configured a step of 0.1 in both CalculiX and preCICE, but an end time of 5 in CalculiX and 1 in preCICE (Max-Time-Windows=10, and 10*0.1=1)
The number of time windows must not be confused with max-iterations, set to 50, which configures the number of iterations per time window in the context of implicit coupling.