Frequency analysis of sandwich plate with active SMA hybrid composite face-sheets and temperature dependent flexible core

In this research, a new finite element model is presented for frequency analysis of a sandwich plate with composite face sheets embedded with pre-strained SMA wires under thermal condition. Mechanical properties of a flexible core are considered temperature dependent. The mixed LW/ESL models in the framework of Carrera's Unified Formulation are employed in this study in order to increase the accuracy of the results with low computational cost. In this regard, the nonlinear strains are used for obtaining the thermal effects and also the effect of recovery stresses in the SMA wires. The constitutive equation proposed by Brinson is used for modeling the recovery stresses in the SMA wires. In this research, the total stiffness of the structure is categorized to essential and acquired stiffness types and results are more discussed. Results show that as the temperature increases, the natural frequencies of the classic sandwich plate decreases due to the degradation of the core's properties, while, by using the active SMA wires, the stiffness of the sandwich plate can be improved and therefore has a positive effect on the natural frequencies of the sandwich plate.