The static funnel is a method for getting converged static equilibrium simulations in Adams. They are particularly useful when a model struggles to converge in a normal static simulation. By using static funnels, you can dramatically increase the likelihood of convergence. This post will walk you through the process of setting up and running a static simulation with static funnels in Adams.

What is a Static Funnel?

If your model struggles to converge in a static simulation, you can try to run multiple static simulations in sequence. Each static simulation can have tighter and tighter convergence criteria. The first step can be so loose that it’s essentially guaranteed to converge. The next step can be tighter, and so on until the final step has the desired convergence criteria.

Setting up a Static Funnel

The best way to run a static funnel is with a scripted simulation. In the ribbon, go to Simulation>Setup>Create a new Simulation Script and place the static funnel wherever you would normally run a static simulation.

Example

Here is an example of a script that runs a static funnel:

EQUILIBRIUM/error=1.0E-1, imbalance=1.0E-1, maxit=500
SIMULATE/statics
EQUILIBRIUM/error=1.0E-2, imbalance=1.0E-2, maxit=50
SIMULATE/statics
EQUILIBRIUM/error=1.0E-3, imbalance=1.0E-3, maxit=50
SIMULATE/statics
EQUILIBRIUM/error=1.0E-4, imbalance=1.0E-4, maxit=50
SIMULATE/statics
EQUILIBRIUM/error=1.0E-5, imbalance=1.0E-5, maxit=50
SIMULATE/statics
EQUILIBRIUM/error=1.0E-6, imbalance=1.0E-6, maxit=50
SIMULATE/statics

This script runs six static simulations in sequence. Each simulation has a tighter convergence criteria for error and imbalance. Each simulation starts from the previous simulation’s converged state.

If one of the simulations fails to converge, the following simulation will start from the end of the last converged simulation. So, if the last iteration fails, but the second to last iteration’s criteria was good enough to proceed, then the simulation can continue.

Conclusion

Now you can stop fighting with your statics simulations and start actually studying dynamics!