Mechanical behavior of cyclically loaded PZT
- National Inst. of Standards and Technology, Gaithersburg, MD (United States)
- Seoul National Univ. (Korea, Republic of)
Uses of intelligent materials which involve the application of force or the generation of displacements will require the incorporation of some form of actuator material into the overall structure. Typically, these types of applications will result in the generation of cyclic loads on the actuator; depending upon the specific application, the frequency of the loading could be low, e.g., for positioning components, or relatively high, e.g., for damping out vibrations in machining tools. Nevertheless, the cyclic nature of the loading raises the specter of damage and, ultimately, failure arising from cyclic loading processes which would not be predicted by traditional mechanical properties test methods. It has been found that PZT loaded cyclically sometimes fails at loads below its nominal strength, as measured by traditional, monotonically increasing load tests. Damage mechanisms which come into play as a result of the cyclic loading conditions have been postulated as the reasons for this behavior. Recent work investigating the cyclic loading of a PZT-8 material at resonance frequency determined that microcracks were generated in the high stress region of the material. Recent results demonstrate that macrocrack extension appears to be accompanied by domain reorientation whereas microcracks can propagate around PZT grains without affecting the domains, (2) morphology and distribution of microcracks generated under different loading conditions can change dramatically that the qualitative mechanical response of PZT-8 to cyclic loading appears to be insensitive to grain morphology. The results presented imply that stresses generated at the tips of macrocracks are much larger than those at microcracks, that temperature strongly affects the rate of microcrack generation, and that wide distributions in grain size and the presence of large voids do not necessarily result in increased microcrack generation over that seen in 2 {micro}m grain size, small pore material.
- OSTI ID:
- 395250
- Report Number(s):
- CONF-940691-; ISBN 1-56676-171-9; TRN: IM9648%%373
- Resource Relation:
- Conference: 2. international conference on intelligent materials, Williamsburg, VA (United States), 5-8 Jun 1994; Other Information: PBD: 1994; Related Information: Is Part Of Second international conference on intelligent materials: Proceedings; Rogers, C.A.; Wallace, G.G. [eds.]; PB: 1410 p.
- Country of Publication:
- United States
- Language:
- English
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