Amirkabir University of Technology Amirkabir Journal of Mechanical Engineering 2008-6032 54 10 2022 12 22 The Effect of Magnetic Field and Fluid on the Primary and Secondary Frequency Response of Fluid-Conveying Carbon Nanotubes Using a Stress-Driven Nonlocal Integral Model The Effect of Magnetic Field and Fluid on the Primary and Secondary Frequency Response of Fluid-Conveying Carbon Nanotubes Using a Stress-Driven Nonlocal Integral Model 2315 2332 4996 10.22060/mej.2022.21144.7386 FA Ebrahim Mahmoudpour Department of mechanical engineering, Borujerd branch,Borujerd,Iran 0000-0002-3628-9833 Journal Article 2022 03 04 In this article, the nonlinear forced vibrations of carbon nanotubes conveying magnetic nanofluid under a longitudinal magnetic field have been investigated. Using Von Karman's nonlinear strain field and the Euler-Bernoulli beam theory, the equations governing the nonlinear vibrations of carbon nanotubes are extracted. Using the method of multiple scales, the frequency response in primary resonance, superharmonic resonance, and subharmonic resonance is obtained. In order to consider the effects of small size, a stress-driven non-local integral model has been used. In the end, the effect of magnetic fluid and magnetic field intensity on frequency response and force response has been investigated. From the results, it can be seen that the presence of a magnetic field causes the system's vibration amplitude to be unstable and have a limited cycle. In this condition, the vibration response is quasi-periodic. However, the presence of magnetic fluid causes the vibration amplitude to be stable and the time response to alternate; In such a way that the Poincaré diagram shows a point in the phase plane. In the primary resonance, with the presence of the longitudinal magnetic field, as the excitation amplitude increases, the frequency response curves include two sub-amplitudes. One is an asymptotic curve with a horizontal axis and the other is a closed curve. In this article, the nonlinear forced vibrations of carbon nanotubes conveying magnetic nanofluid under a longitudinal magnetic field have been investigated. Using Von Karman's nonlinear strain field and the Euler-Bernoulli beam theory, the equations governing the nonlinear vibrations of carbon nanotubes are extracted. Using the method of multiple scales, the frequency response in primary resonance, superharmonic resonance, and subharmonic resonance is obtained. In order to consider the effects of small size, a stress-driven non-local integral model has been used. In the end, the effect of magnetic fluid and magnetic field intensity on frequency response and force response has been investigated. From the results, it can be seen that the presence of a magnetic field causes the system's vibration amplitude to be unstable and have a limited cycle. In this condition, the vibration response is quasi-periodic. However, the presence of magnetic fluid causes the vibration amplitude to be stable and the time response to alternate; In such a way that the Poincaré diagram shows a point in the phase plane. In the primary resonance, with the presence of the longitudinal magnetic field, as the excitation amplitude increases, the frequency response curves include two sub-amplitudes. One is an asymptotic curve with a horizontal axis and the other is a closed curve. https://mej.aut.ac.ir/article_4996_e586a4f55fb43a540c2e9dab45e00f53.pdf