Modeling of piezoceramics and piezoelectric laminates addressing complete coupling and hysteresis behavior

Smart composite structures have the ability to actively react to environmental disturbance while maintaining or even improving system performance. Piezoelectric sensing and actuation of composite laminates is the most promising concept due to the static and dynamic control capabilities. Essential to the implementation of these smart composites is the development of effective analysis tools that can accurately address piezoelectric coupling effects, stress distributions and even hysteresis behavior under large actuation. This dissertation addresses each of these important topics.; A general framework is developed for the analysis of piezoelectric laminates with surface bonded and embedded sensors/actuators. The developed theory can account for the complete two-way coupling among piezoelectric, mechanical and thermal fields. The higher order theories are developed or used to address transverse shear effects and nonuniform distributions of temperature and electrical fields. The impact of various coupling effects and control authority of smart composite structures is investigated in detail.; To obtain accurate stress and strain predictions for laminated shells with arbitrary thickness, an improved shear deformation theory is developed. To accommodate the complexity of zigzag-like in-plane deformation through laminate thickness, in-plane displacement field is modeled using the superposition of overall first order shear deformation and layerwise functions. By imposing the interlaminar continuity, the number of structural variables is reduced and is independent of the number of layers. The developed theory is validated using available exact solutions and is further used in the analysis of piezoelectric laminates.; To model the significant piezoelectric nonlinearity exhibited under high electrical actuation, a hysteresis model is developed. The nonlinear material model is derived from a new form of elastic Gibbs free energy in terms of the state variables of strain and polarization. Higher order terms are used in the expression to capture ferroelectric nonlinearities. With the introduction of a new material constant, an explicit formulation governing the nonlinear constitutive relationship is obtained by using saturation polarization, remnant polarization, coercive electric field and linear piezoelectric coefficients. The developed nonlinear constitutive relations are applicable in the case of high stroke actuation to utilize the largest possible strain available in piezoceramics.