In recent decades the application of micro/nano electromechanical system for sophisticated energy harvesting devices have increased popularity. In order to design such a sophisticated devices, it is needed to know mechanical behavior of such a structures at micro/nano scale under various thermal condition. The thermal conductivity at nano scale can be reduced significantly at nanoscales. If the size of nanostructure is smaller than phonon mean free path they are scattered on interfaces and thermal conductivity is reduced .It is known that piezoelectric materials converts the mechanical energy into the electrical energy. This electro mechanical coupling is even more pronounced at nano scale where flexoelectric effect is present. Flexoelectricity is size dependent and requires strain gradients in order convert mechanical energy in to electrical. The miro/nano electromechanical systems work in different mutiphysical environment, therefore in order to ensure structural integrity of this sophisticated devices it is needed to have numerical models which take in to account size dependency and electro-thermo -mechanical interaction.  The nonlocal higher order heat conduction equation with incorporated size effects will be considered. Based on generalized heat conduction model and strain gradient elasticity theory with one microstructural length scale parameter the new model will be established. The interaction of thermal mechanical and electrical fields and influence of the size effect will be numerical modeled.

Acknowledgment: The financial support by the Science Grant Agency of the Slovak Republic through the grant VEGA-2/0084/24 is greatly acknowledged.