The establishment of coupled magneto-electro-thermo-elastic theory with the consideration of surface and non-local effects and its application in laminated nano-devices

A fully coupled linear two-dimensional (2D) magneto-electro-thermo-elastic (METE) laminated plate theory considering non-local and surface effects is established for the first time based on the principle of virtual work and Mindlin's theory. This theory is suitable in macro and micro scales, and these equations obtained are general and can be reduced to some cases at particular conditions. After theoretical and numerical validation, the performance of a nano-scaled energy harvester made of piezoelectric and piezomagnetic layers is studied by using of the 2D METE theory as a specific example. A critical thickness is obtained and numerical results show that surface effect plays key role on the size-dependent behavior, including the resonant frequency, output voltage, output power, and magneto-electric coupling coefficient. The present study may be useful to multi-field coupling analysis of size-dependent nanostructures.