Production of high tip deflection in a piezoelectric bimorph laminar actuator by applying high voltage is limited by many physical constraints. Therefore, piezoelectric bimorph actuator with a rigid extension of non-piezoelectric material at its tip is used to increase the tip deflection of such an actuator. Research on this type of piezoelectric bending actuator is either limited to first order constitutive relations, which do not include non-linear behavior of piezoelectric element at high electric field, or limited to curve fitting techniques. Therefore, this paper considers high electric field, and analytically models tapered piezoelectric bimorph actuator with a rigid extension of non-piezoelectric material at its tip. The stillness, capacitance, effective tip deflection, block force, output strain energy, output energy density, input electrical energy and energy efficiency of the actuator are calculated analytically. The paper also discusses the multi-objective optimization of this type of actuator subjected to the mechanical and electrical constraints.
Piezoelectric bimorph laminar actuator of tapered width exhibits better performance for out-of-plane deflection
compared to the rectangular surface area, while consuming equal surface area. This paper contains electromechanical
analysis and modeling of a tapered width piezoelectric bimorph laminar actuator at high electric field
in static state. The analysis is based on the second order constitutive equations of piezoelectric material, assuming
small strain and large electric field to capture its behavior at high electric field. Analytical expressions
are developed for block force, output strain energy, output energy density, input electrical energy, capacitance
and energy efficiency at high electric field. The analytical expressions show that for fixed length, thickness, and
surface area of the actuator, how the block force and output strain energy gets improved in a tapered surface
actuator compared to a rectangular surface. Constant thickness, constant length and constant surface area of
the actuator ensure constant mass, and constant electrical capacitance. We consider high electric field in both
series and parallel electrical connection for the analysis. Part of the analytical results is validated with the
experimental results, which are reported in earlier literature.