The effect of different foam structures on the thermo-mechanical vibration of MEE smart nano plates

Abstract

This study investigates the thermomechanical vibration behavior of magneto-electroelastic (MEE) functionally graded (FGM) smart nanoplates composed of CoFe₂O₄ and PZT-5H materials with different foam distribution patterns. The equations of motion were derived using higher-order shear deformation theory and nonlocal strain gradient theory within the framework of Hamilton's principle. The FGM nanoplates have a composition that gradually changes throughout the thickness, containing PZT-5H on the bottom surface and CoFe₂O₄ on the top surface. In this study, four different foam models uniform, symmetric, top-density, and bottom-density—were investigated; their effects on frequency and vibrational buckling behavior under temperature were studied. The results show that the highest thermal vibrational buckling resistance is obtained in the bottom foam structure, while the lowest resistance is observed in the uniform foam structure. Increasing the porosity ratio reduces both the fundamental frequency and the buckling temperature. The applied external electrical potential reduces the system rigidity and decreases the frequency due to the electro-elastic effect, while the magnetic field, conversely, increases rigidity and vibration resistance. Furthermore, nonlocal and size-effect parameters play a significant role in the dynamic response. Overall, it has been shown that the vibration performance of FGM-MEE smart structures can be improved by optimizing the foam structure, material transition, and multiple physical loadings. Such structures offer great potential for advanced technology applications such as spacecraft structural panels, high-temperature piezoelectric energy harvesters, magnetic field-controlled micro-actuators, smart sensor systems, and MEMS-based vibration dampers.