Linear Static Behavior of Damaged Laminated Composite Plates and Shells

Abstract

A mathematical scheme is proposed here to model a damaged mechanical configuration for laminated and sandwich structures. In particular, two kinds of functions defined in the reference domain of plates and shells are introduced to weaken their mechanical properties in terms of engineering constants: a two-dimensional Gaussian function and an ellipse shaped function. By varying the geometric parameters of these distributions, several damaged configurations are analyzed and investigated through a set of parametric studies. The effect of a progressive damage is studied in terms of displacement profiles and through-the-thickness variations of stress, strain, and displacement components. To this end, a posteriori recovery procedure based on the three-dimensional equilibrium equations for shell structures in orthogonal curvilinear coordinates is introduced. The theoretical framework for the two-dimensional shell model is based on a unified formulation able to study and compare several Higher-order Shear Deformation Theories (HSDTs), including Murakami’s function for the so-called zig-zag effect. Thus, various higher-order models are used and compared also to investigate the differences which can arise from the choice of the order of the kinematic expansion. Their ability to deal with several damaged configurations is analyzed as well. The paper can be placed also in the field of numerical analysis, since the solution to the static problem at issue is achieved by means of the Generalized Differential Quadrature (GDQ) method, whose accuracy and stability are proven by a set of convergence analyses and by the comparison with the results obtained through a commercial finite element software.

Comparison of small scale effect theories for buckling analysis of nanobeams

“…3 (carbon atoms are demonstrated in darker color in SiCNT structure). Nanotubes have been modeled as plate, shell, rod, and beam in literature [23][24][25][26][27][28][29][30] to make bending [31,32], buckling [33] , vibration [34] analyses possible theoretically. In this paper, nanotubes are modeled as cylindrical beam by using Euler-Bernoulli beam model.…”

Effect of Curvilinear Reinforcing Fibers on the Linear Static Behavior of Soft-Core Sandwich Structures

“…As far as two-dimensional domains are concerned, the present approach can be easily generalized as shown in [23,117]. In these circumstances, the grid distribution (63) is applied along the main directions α 1 , α 2 by specifying the number of discrete points as I N , I M , respectively.…”

“…Advanced composite materials are mainly developed to design stiffer and lighter structures, characterized by an improved and more efficient mechanical behavior. Among them, fiber-reinforced media [1][2][3][4], laminated and sandwich composites [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24], Functionally Graded Materials (FGMs) [25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40][41], nanocomposites [42][43][44][45][46] and metamaterials [47][48][49][50]…”

Stress distributions in nanocomposite sandwich cylinders reinforced by aggregated carbon nanotube

“…These structures usually consist of a thick low strength core and two thin stiff outer face sheets. The face sheets have been designed to resist the applied loads and the core layer is employed to stabilize the structure and to withstand shear loads . Due to the high strength‐to‐weight ratio and corrosive resistances of sandwich structures, they are widely used in various industrial applications such as aerospace, automobile, and biomechanics .…”