The stiffness varies with the angle θ. If the leaf spring is combined with others the following holds*.
Angle dependent linear stiffness:
Linear stiffness perpendicular to the drawing:
* If a folded leaf spring is used individually, the stiffness varies according some boundary conditions, see other Precision Point sheet.
Angle dependent stiffness of the folded leaf springs:
Combined radial stiffness:
Combined linear z stiffness:
Combined rotational stiffness:
Note that in the stiff direction of 1 folded leaf spring, the other is not stiff, so
only the unidirectional stroke can be used.