Electromechanical behaviour of PZT with real domain structure

It is generally assumed that domain switching is the reason for non-linear hysteresis loops of piezoceramics. Although several published models allow to reproduce the experimentally observed hysteresis loops, they do not take into account the real domain structure and switching of domains. A model predicting the electromechanical behaviour considering the real domain structure and switching of these domains was developed. Using SFM the real structure of a 2 mol% lanthanum doped PZT was investigated and used for a finite element model. Each domain was modelled as a substructure with a different set of material parameters. The FE-analysis included the deformation and polarization induced by external loads as well as the remanent fields. Under loading each domain switched when its energy release rate exceeded a critical value. Using small loading steps only few domains switched at the same time so that the interaction of neighbouring domains could be investigated. The simulated remanent state was compared with the experimental remanent state from SFM and showed good agreements.