Stress-driven nonlocal elasticity for the instability analysis of fluid-conveying C-BN hybrid-nanotube in a magneto-thermal environment

The Eringen's strain-driven nonlocal differential model is well-established to exhibit inconsistencies when applied to bounded continua of applicative interest. The stress-driven nonlocal theory leads instead to well-posed nonlocal elastic formulations demonstrating stiffening structural responses. In the present article, using the stress-driven nonlocal model, a comprehensive analysis is conducted to explore the vibrational characteristics and critical divergence velocity of a hybrid-nanotube constructed by carbon (C) and boron nitride (BN) nanotubes conveying magnetic fluid. The impact of size-dependence, magnetic field and thermal medium on the dynamic behavior of the systems is included in the proposed model. The obtained governing equations of two-segment nanotubes are then examined using the finite element method. It is interestingly showed that the threshold of the divergence/flutter instability of the system would be enhanced by employing a hetero-nanotube instead of a nanotube composed of a uniform material. Furthermore, the results demonstrate that the configuration of the mode shapes may be dramatically changed for a nanotube conveying fluid. Therefore, the classical modes do no longer exist, and should not be considered in the dynamics of the system. It is also shown that by assuming a low temperature medium, the critical velocity increases by increasing the temperature and decreases in the case of high temperature.