Discussion Forum

Dear COMSOL users,

I have the following problem. I would like to fit a model of an electrolysis cell to experimental current-voltage-curves (CVCs) by finding some effective parameter values. The bias voltage is a global parameter in my model, and in the experimental data the output current is given as a function of bias voltage.

The problem is, that the model contains some very strong nonlinearities, and thus the solution is always achieved by multiplying the nonlinearities with a damping parameter, starting at a value of 10^-10 and gradually relaxing it to 1 in an auxiliary sweep. When I use the optimization module, in the very first step it relaxes the damping, but then, when it would try to calculate the model output for the bias voltage values given in the experimental data, it always wants to go from a damping value of 1, and of course, the model doesn't converge.

Can anybody help me at least in achieving that the optimization solver ramps the damping parameter for all bias voltage values?

In my opinion the cheapest solution would be to relax the damping, ramp the voltage, get the CVC (integral of the current density on the boundary calculated for all bias voltage values) and interpolate between the points of the calculated CVC for the experimental values. Might this be achievable somehow, too?