Microstructural crystal morphology, which affects strongly on macroscopic electromechanical behaviors of polycrystalline piezoelectric ceramics, was analyzed using electron backscatter diffraction method. We coated piezoelectric ceramics with amorphous osmium to defend against electrification caused by electron beam, and measured crystal orientations of 140×120 µm 2 over region at 0.32 µm scanning interval. Then the obtained crystal orientations were applied to a multiscale finite element analysis to evaluate the relation with macroscopic mechanical and electrical properties. Especially, we investigated on finite element modeling conditions to sample crystal orientations, and presented a representative volume element of microstructure to compute the macroscopic homogenized properties and the microscopic localized responses.
Health monitoring system equipped with blood extraction pump is one of the important problems for new medical technology to support the advanced age society. In this paper, a new piezoelectric actuator for blood extraction pump was proposed to increase volumetric change in pump. We devised the geometry of piezoelectric actuator with some slits that allows the stretching and contracting deformation in in-plane direction to create large deflection in outof-plane direction. Focusing on a disc-type bimorph plate with some slits, the deformations under static electric load have been analyzed by finite element method with consideration of two geometric parameters, length l and width w of slits. The computational results indicated that the deformation of bimorph actuator changes from complex mode to single mode according to increase of slit length, and that single mode presents remarkable increase of deflection under surrounding-fixed condition. And then, a bimorph actuator with 4 slits l = 2.0, w = 0.5mm has been manufactured as an experiment. As a result, a developed actuator was proved to increase the deflection under dynamic electric load compared with a conventional bimorph actuator without slits.
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