Finite element homogenization of active composites at different dimensional scales

In recent years, multiphase ceramic composites (porous ceramics, composites ceramics/ceramics, ceramics/crystals, ceramics with modified interface properties, nanocomposites, etc.) are widely used for industrial applications.... [ view full abstract ]

In recent years, multiphase ceramic composites (porous ceramics, composites ceramics/ceramics, ceramics/crystals, ceramics with modified interface properties, nanocomposites, etc.) are widely used for industrial applications. The simulation of active materials at various scale levels helps to enhance the technologies of directed change of the properties of these materials and provide a qualitative improvement of the transducers and devices characteristics.

Furthermore, it should be noted that modeling of micro- and nanomaterials and devices has some specific features. It is known that a range of nanomaterials have abnormal mechanical properties. Thus, the experimentally observed fact is the stiffness increases with reducing the sizes of nanoobjects. One of the factors that are responsible for this behavior of nanomaterials can be the surface effect. In connection to this, the main difficulty can consist in the extension of this approach to the nanoscale elements of active composites. Therefore, here it is logical to consider not only the mechanical surface effects, but also the surface effects of other coupled fields.

The present research concerns direct finite element modeling of such active composites as thermoelastic, piezoelectric and magnetoelectric mixture two-phase composites. The proposed technique is based on the models of micro- and nanoscale materials with surface and interface effects, the effective moduli method, the modelling of representative volumes, and the use of finite element technology. As examples, we investigate the porous piezoelectric ceramics, the composites of piezoceramics/crystallite types and the thermoelastic composites. For these materials we use models of representative volume with different types of connectivity, take into account for the heterogeneities near the interfaces and the surface effects. For numerical solution of static homogenization problems in representative volumes we used ANSYS and ACELAN-COMPOS finite element software. The computational results enabled us to estimate the influence of the micro- and nanostructures on the values of the effective moduli.