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Abstract
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The present study investigates free vibration and flutter instability analyses of a sandwich microbeam subjected to supersonic fluid flow. The microbeam comprises functionally graded (FG) porosity cores, with top and bottom sheets reinforced by carbon nanotubes (CNTs). Mechanical properties of FG porous-nanocomposite sandwich microbeam are determined using the rule of mixture and the Ashleby-Mori-Tanaka method. Euler-Bernoulli, Timoshenko, and Reddy beam theories are used while the modified couple stress theory (MCST) accounts for size effects. linearized piston theory and Pasternak foundation is considered to model supersonic fluid flow and elastic medium. In the analysis of free vibrations, natural frequencies and corresponding mode shapes are extracted and in flutter analysis, the variations in natural frequencies with respect to the aerodynamic pressure of the fluid flow are plotted to calculate the critical pressure. A parametric study is conducted to investigate the impact of various characteristics include the geometric properties porosity and distribution pattern of pores, mass fraction, type and distribution pattern of CNTs, length scale parameter, and boundary conditions. Based on the results, it can be concluded that using CNTs with smaller chiral indices leads to a maximum increase in the microbeam's natural frequencies and achieves the highest aeroelastic stability. The findings of this research can be utilized in the design and analysis of microturbines as well as equipment used in biomechanical engineering.
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