Abstract
A laminated piezoelectric bimorph actuator with a graded compositional distribution of PZT was fabricated, and its deflection characteristics were evaluated. Using experimentally determined compositional dependency of elastic and piezoelectric properties in the PZT/Pt composites, the modified classical lamination theory and the finite element method were applied to find the optimum compositional profile that will give a lager deflection and smaller stress, simultaneously. The miniature bimorph-type graded actuator that consists of a composite internal-electrode (PZT/30vol%Pt) and three piezoelectric layers of different composition (PZT/0-20vol%Pt) were fabricated by powder stacking and sintering. The deflection was found to strongly depend on the composition distribution profile. Under an applied electric field of 100Vm^<-1>, the actuator with an optimum composition profile exhibited a curvature of up to 0.03m^<-1>, which is satisfactory performance for this kind of actuators. The stress generated on actuation was estimated to be as low as 0.4MPa, which is much smaller than those of conventional directly bonded actuators and will assure a long actuation life.
