Vibrational characteristics of attached hemispherical-cylindrical ocean shell-structure reinforced by CNT nanocomposite with graded pores on two-parameter elastic foundations applicable in offshore components

Abstract

One of the essential simulations of offshore components of ocean and marine structures can be counted as a modeling of the interaction between the systems and soil's behavior on the dynamic of the offshore systems. Based on this, for the first time, the fundamental frequencies of the porous nanocomposite attached hemisphere-cylinder shell system (AHCSS), counted as ocean and marine offshore structures, reinforced by carbon nanotube (CNT) rested on the Winkler-Pasternak elastic foundations, added up as soil's behavior simulation, are investigated in this paper. In detail, to expand the effectiveness of the CNT along the matrix, eight distinct functionally graded (FG) forms besides uniform distributions are prepared. Also, two forms of porosity which are FG distributed along the FG-CNT nanocomposite, are realized to add the effect of the porosity on the nanocomposite. Addedly, the first shear deformation theory and Donnell's scheme are coupled to arrange the affiliations of the AHCSS. In addition, Hamilton's principle gets the central motion equations (CMEs) of the AHCSS. Then, the half-analytical procedure, named the generalized differential quadrature method, discretizes the CMEs. Finally, the eigenvalue method finds the frequencies of the porous nanocomposite AHCSS. Remarkably, various numerical samples are prepared and solved to indicate the effects of the Winkler-Pasternak foundations, boundary cases, porosity forms, FG-CNT models, and physical values on the frequencies of the porous nanocomposite AHCSS.