Piezoelectric materials exhibit hysteresis in the field-strain relation at
essentially all drive levels. Furthermore, this nonlinear relation is
dependent upon both prestresses and dynamic stresses generated during
employment of the materials. The accurate characterization of this nonlinear
and hysteretic material behavior is critical for material characterization,
device design, and model-based control design. In this talk, we will
discuss the characterization of hysteresis using the homogenized energy
model (HEM) framework. At the mesoscale, energy relations characterizing
field and stress-dependent 90 and 180 degree switching are used to develop
fundamental kernels or hysterons. Material and field nonhomogeneities are
subsequently incorporated by assuming that certain parameters are
manifestations of underlying densities. This yields a macroscopic model
that accurately characterizes the fundamental material behavior yet is
sufficiently efficient for optimization and control implementation.
Attributes of the model will be illustrated through comparison to
experimental data.