Systematic design of displacement-amplifying mechanism for piezoelectric stacked actuators using topology optimization

Displacement-amplifying mechanisms can be systematically designed using topology optimization. Due to the special need of large displacement amplification for piezoelectric stacked actuators, the objective function should be formulated properly. Among output stroke, magnification factor and work ratio, magnification factor better describes the design goal of displacement amplifier and is thus adopted in this work. To depict the dynamic operation of displacement amplifier, undamped harmonic response is used in the formulation. The design problem is thus posed as a material distribution problem, which maximize the dynamic magnification factor by varying the thickness of 2-D domain. Plane stress solid is assumed for the design domain. Stiffness of the actuator and the workpiece is included in the analysis. The design problem is solved by Method of Moving Asymptotes or MMA. To show the viability of this design methodology, two examples of magnification mechanism for printer head driven at different excitation frequency are presented.