Can anyone explain to me why a bimorph has a metal in between the two piezo-layers?
Maybe it provides the common electrical connection to the far end of the bimorph cantilever.
No, I'm not sure which is why I say maybe.Are you sure? I've tried searching for it many places but I just can't find anything about it.
Piezo Systems said:Parallel Operation: Parallel operation refers to the case where the supply voltage is applied to each layer individually. This means accessing and attaching wires to each layer. A 2-layer bending element wired for parallel operation requires three wires (one attached to each outside electrode and one attached to the center shim), as shown in Figure-18. For the same motion, a 2-layer element poled for parallel operation needs only half the voltage required for series operation.
Piezo Systems said:The metal shim sandwiched between the two piezo layers provides mechanical strength and stiffness while shunting a small portion of the force.
Piezo Systems said:The brass shim reinforcement laminated between the two piezoelectric layers is an economical approach to producing a rugged actuator.