Actuator assemblies, mechanical assemblies including the actuator assemblies, and methods of fabricating the same are disclosed herein. The actuator assemblies include a piezoelectric element having a first side and a second side, a first electrode in electrical communication with the first side, and a second electrode in electrical communication with the second side. The first electrode includes a flexible, electrically conductive membrane. The mechanical assemblies include a first structure, which includes a first interface surface, a second structure, which includes a second interface surface, and the actuator assembly. The actuator assembly is configured to provide a motive force for relative motion between the first structure and the second structure. The methods include defining a first electrode on a first side of a piezoelectric element and defining a second electrode on a second side of the piezoelectric element. The first electrode includes a flexible, electrically conductive membrane.