大振幅下における圧電セラミックの力学的挙動 : 圧電セラミックトランスの場合(<小特集>セラミック材料小特集)
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概要
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Mechanical properties of piezoelectric ceramic transformers were investigated as an example of e dynamic behavior of piezoelectric ceramics under large amplitude operation. The static and dynamic strengths were measured on the driver and generator sections of the transformer. The difference in heat production between the sections was recognized, which proved to be derived from l orientation discrepancy between the poling and stressing directions. A large non-linearity common to the mechanical strength and the heat-generation phenomenon as found to be associated with the non-linearity in resonance characteristics of resonators. Mechanical fracture of piezoelectric ceramic transformers, which is the ultimate event under large amplitude stress, occurred mainly in the secondary portion. This phenomenon is understandable from the difference in static tensile strength between the primary and secondary portions. The mechanical strength of piezoelectric ceramics also depended on their grain size as in the case of other ceramics. The propagation path of the crack generated was transgranular or intergranular depending upon grain size. Griffith cracks were hardly observed in any specimen tested. The existence of etch pits, which may be due to dislocations, was discovered for the first time in piezoelectric ceramics. Strain-hardening was also recognized. From the above experimental results, a new model for the mechanical break-down mechanism in piezoelectric ceramics was proposed.
- 社団法人日本材料学会の論文
- 1981-10-15