Active layered composites: A variable kinematics approach with stimulus expansion model for piezo-actuators and hydrogels

Active materials are often applied in the form of plate-like smart composites. Therein, they are combined with other (active or passive) materials that serve different purposes, such as providing mechanical counterpoints, protection against multi-field influences, or electrical functionality. Furthermore, sensoric layers can be included. For an enhanced description of the mechanical response of Soft-Hard Active-Passive Embedded Structures (SHAPES) in plate configuration, we combine two approaches: (i) A variable kinematics approach called sublaminate Generalized Unified Formulation (sGUF), which allows the choice of adequate kinematics for each physical layer, and (ii) the Stimulus-Expansion-Model (SEM) for description of active behavior. We present results for SHAPES with polymer gel layers and for piezo-ceramic layers. The current sGUF-SEM modeling approach has been protypically implemented along with a Navier-type solution. This allows the assessment of combinations of different passive and active materials inside plate-like composites. Excellent agreement with reference solutions from literature and/or from three-dimensional Finite Element simulations in commercial software tools has been found. The promising preliminary results presented in this work suggest further steps to be considered: the implementation of sGUF-SEM into more general numerical solution methods, such as Finite Element or Ritz methods, and the integration of the physics of additional active materials.