Thermomechanical nonlinear stability of pressure-loaded CNT-reinforced composite doubly curved panels resting on elastic foundations

Abstract

Nonlinear stability of nanocomposite spherical and cylindrical panels reinforced by carbon nanotubes (CNTs), resting on elastic foundations and subjected to uniform external pressure in thermal environments is investigated in this paper. CNTs are embedded into matrix phase through uniform distribution (UD) or functionally graded (FG) distribution, and effective properties of CNT-reinforced composite are estimated through an extended rule of mixture. Governing equations are based on classical shell theory taking geometrical nonlinearity, initial geometrical imperfection and panel-foundation interaction into consideration. Approximate solutions of deflection and stress functions are assumed to satisfy simply supported boundary conditions and Galerkin method is applied to obtain nonlinear load-deflection relation. Numerical examples show the effects of volume fraction and distribution type of CNTs, in-plane condition of edges, curvature of panel, thermal environments, elastic foundations and imperfection size on the nonlinear response and snap-through instability of the curved panels. The present study reveals that efficiency of CNT distribution type depends on curvature of panel and in-plane behavior of boundary edges, and bifurcation type buckling response of pressure-loaded panels may occur at elevated temperature.

Thermal postbuckling analysis of FG-CNTRC doubly curved panels with elastically restrained edges using Reddy's higher order shear deformation theory

“…It is recognized from Eqs. (25) and (26) that if q = 0 the thermally loaded panels will be deflected at the onset of heating and, in general, no bifurcation buckling occurs. Especially, bifurcation buckling response may occurs for imperfect panels when imperfection size µ satisfies a special condition predicted from Eq.…”

“…Postbuckling behavior of FG-CNTRC doubly curved panels with freely movable edges under external pressure is studied by Shen and Xiang [24] making use of HSDT, asymptotic solutions and a perturbation technique. Trang and Tung [25,26] presented analytical investigations on the nonlinear stability of thin and first order shear deformable FG-CNTRC doubly curved panels under external pressure taking into account the effects of elastic foundations and tangential constraints of boundary edges. Thermal stability of composite and nanocomposite curved panels is a complicated problem.…”

Nonlinear response of doubly curved sandwich panels with CNT-reinforced composite core and elastically restrained edges subjected to external pressure in thermal environments

“…The idea of optimal distribution of CNTs motivates the concept of functionally graded carbon nanotube reinforced composite (FG-CNTRC) [3] in which CNTs are embedded into the matrix in such a way that their volume is varied in the thickness direction of structure according to functional rules. Shen's propositional work [3] stimulated subsequent investigations on the static and dynamic responses of FG-CNTRC structures [4][5][6][7][8][9][10][11][12][13]. Based on a higher order shear deformation theory (HSDT) and a twostep perturbation approach, Shen and coworkers [14][15][16] investigated the postbuckling of pressure-loaded doubly curved panels made of functionally graded (FG) material, CNTRC and graphene-reinforced composite (GRC).…”

“…As an extension of previous works [9,10], this paper aims to analyze the effects of tangential edge constrains, preexisting thermal environments and elastic foundations on the nonlinear stability response of doubly curved sandwich panels with FG-CNTRC core layer subjected to uniform external pressure. Formulations are based on the first order shear deformation theory taking into account geometrical imperfection, von Kármán-Donnell nonlinearity and interactive pressure from elastic foundations.…”

Band gap manipulation of viscoelastic functionally graded phononic crystal

“…Unlike most nanomaterials, whose mechanical properties are homogeneous in macroscale [12], functionally graded materials (FGMs), first applied in aerospace structures, are deliberately manufactured to have mechanical properties with continuous spatial variations [13,14]. Recently, the concept of FGM has been introduced into the carbon nanotube-reinforced composites and some nonlinear mechanical characteristics were studied [15,16]. Nowadays, FGMs are applied widely in various structures as members or coatings [17].…”