Stability analysis of a spinning soft-core sandwich beam with CNTs reinforced metal matrix nanocomposite skins subjected to residual stress

Abstract

The stability of a soft-cored spinning viscoelastic sandwich beam and carbon nanotubes (CNTs) reinforced metal matrix nanocomposites (MMNCs) skin subjected to residual stress have been investigated. The metal matrix nanocomposites (MMNCs) skins are symmetrical and isotropic. In addition, these skins reinforced with uniform and functionally graded (FG) distributions of carbon nanotubes (CNTs) are considered. The soft-core of the sandwich beam is deemed to be elastomeric and has internal damping of viscoelastic type. The skin layers of the sandwich beam are subject to residual stresses caused by the production process. Also, the effective material properties of skins are obtained using the rule of mixture (ROM) and Halpin-Tsai (H-T) micromechanics models. First, the governing equations of motion of a spinning viscoelastic sandwich beam are obtained using the Hamilton principle. Then, the sandwich beam's natural frequencies are calculated using the differential quadrature method (DQM). The effects of CNTs distribution, nanotube volume fraction, spinning speed, critical loading, the thickness of the core, axial force, and residual stress on the sandwich beam's natural frequency and stability regions are investigated. According to the results of this study, based on the sandwich beam's different spinning speeds, it is possible to estimate the optimal amount of core thickness to prevent instability, which can be very important in the design of spinning sandwich structures.