Size-dependent dynamics and instability of sandwich magnetorheological elastomer (MRE)-cored shells in presence of moving flow, based on modified first strain gradient theory

摘要

This paper is devoted to developing a comprehensive size-dependent modeling for dynamic and stability analysis of a sandwich micro-shell with magnetorheological elastomer (MRE) core, subjected to a moving fluid flow. The mathematical formulation of this model is conducted on the basis of Donnell's shell theory and modified first strain gradient theory (MFSGT). Additionally, perturbation pressure of the fluid flow is considered to model and add the effect of the existing fluid to the governing fluid-solid interaction (FSI) equations. After mathematical modeling, the obtained governing motion equations are solved analytically to attain the dynamic characteristics of the system namely imaginary and real parts of eigenvalues, frequencies and loss factors of the system. Verification study is implemented and thereafter the exact influences of the involved parameters such as length scale parameter, circumferential wave number, moving flow velocity, applied magnetic intensity to the smart core and MRE core thickness on the dynamic and stability response of the system are examined and discussed in detail for first three modes. The results show an excellent and considerable role of the MRE core properties on dynamic and stability control of the system. This effect could be detected in forms of diminishing some possible instabilities of various modes or expanding the stable region of the system. It is hopeful that, the analysis and acquired results may provide a data bank; helpful for increasing the knowledge about MRE-based sandwich structures and designing more adaptable and efficient systems benefiting from advanced and smart materials.