Franci
Without knowing what your model looks like a general tip:
Normally for such a case you would use a prescribed displacement to a surface of the part that is supposed to move away from the snap and define a measure determining the reaction force required to achieve this displacement.
The graph results for this measure would show you the required force.
This analysis would of course require; Contact (for the snap connection) and large deformations, as well as results for a lot of output steps.
If you would post your model, somebody here is likely to complete it for you. You require an advanced simulate license for this.
Erik
