For the different types of co-simulations various coupling algorithms are available:
A transient particle code is coupled to a static structure model. The forces are time integrals or time averages and weigh a static structural model.
Synchronous time increment:
Both partners of the co-simulation use the identical time increment. Here, two methods can be distinguished.
- Minimal time step:
Both partner-codes accept a minimum time increment, which is continuously determined and synchronized between the codes.
- Master-slave concept:
The time increment is defined by only one of the partner-codes. The method may indeed lead to numerical instabilities in explicit codes, on the other they hand significantly reduce the computation time for implicit codes.
Asynchronous time increment
Each code uses the best, perhaps the largest time increment. This requires storing a time history, time interpolations and time integrations.
Also in this case, two variants are possible.
Each code is working at the optimum time for him increment.
The time increment of the slower code is adaptively adjusted by the computation time requirement of the faster solver in order to minimize interpolation errors with optimal utilization of the computer.