piezoelectric cantilever coupled with an external electric circuit

Hi Ivan,

we're still working on piezoelectric cantilever coupled with an external electric circuit. We obtain very good results in the case of open circuit. When we introduce a load resistance the piezoelectric material seems to not see the coupling with the circuit.

We built the circuit model in this way
- terminal in the physics "Piezoelectric Devices" on the upper surface of the piezoelectric material, option terminal: circuit
- Ground in the surface between the passive and the piezoelectric layer
- terminal + resistor + ground in the physics "Electrical Circuit", option terminal: terminal voltage

We create a force with the function "step" which grows slow from 0 to 1 and then remains constant for all the simulation. We expect that the potential increases when the force grows and decreases when the force is constant.
Moreover the peak voltage has to depend on the values of load resistance,

Theese two things does not happen.

What do you think?

We use version 4.3

Andrea, Alessandro e Giacomo