[FEMM] Radial force in axymmetric problem

["Fabio" <fmilanesi@xxxxxx>]

Hi, everyone.

I have used FEMM to simulate an air inductor for used to reduce short
circuit current.
I try calculate the force between turns using Lorentz force, force via
weighted stress tensor  an force via stress tensor ( contour ).
I get good results for z component of this force. Obviously the total r
force on one turn is zero for the axial symmetry but if a consider a small
part of turn there is a local radial force.
I try to calculate this force using the virtual work principle : F = dE/dr =
1/2* i^2* dL/dr.
First i calculate the inductance L0 of the circuit , then i give a small
displacement dr  to all turns on the external layer and i calculate again
the inductance L1.
Then i calculate the force F =  1/2* i^2*(L1-L0)/dr and divide for the
number of turns and for the length of one turn to get the force per unit of
lenght.
Now the question :
is there a faster way in order to  calculate radial force in postprocessor ?

Thanks and best regards
Fabio