Z.X. Lei

Buckling of FG-CNT reinforced composite thick skew plates resting on Pasternak foundations based on an element-free approach

Buckling behavior of functionally graded carbon nanotube (FG-CNT) reinforced composite thick skew plates is studied. The element-free IMLS-Ritz method is used to obtain the buckling solutions to this problem. The first-order shear deformation theory (FSDT) is employed for formulation of the energy functional to incorporate the effects of transverse shear deformation and rotary inertia. Using the IMLS approximation in the field variables and minimizing the energy functional via the Ritz procedure, a discretized eigenvalue equation of the problem is derived. The buckling solution can be obtained through solving this eigenvalue problem. The numerical stability of the IMLS-Ritz method is validated through convergence studies. The accuracy of the IMLS-Ritz results is examined by comparing with the known solutions. Close agreement is found from the comparison study. Besides, parametric studies are conducted for various types of CNTs distributions, CNT ratios, aspect ratios, plate geometries and thickness-to-height ratios under different boundary conditions.

Meshless modeling of geometrically nonlinear behavior of CNT-reinforced functionally graded composite laminated plates

A geometrically nonlinear analysis of carbon nanotube reinforced functionally graded (CNTR-FG) composite laminated plates is presented. Single-walled carbon nanotubes (SWCNTs) are selected as reinforcement and the effective material properties of CNTR-FG plates are assumed to be graded through the thickness direction in each layer. The two-dimensional displacement fields of the plates are approximated by a set of meshless kernel particle functions. For the purpose of eliminating shear locking, a stabilized conforming nodal integration scheme is employed to evaluate the system bending stiffness, and the membrane and shear terms are calculated by the direct nodal integration method. Parametric studies are conducted to investigate the effect of various types of CNT distribution, CNT volume fraction, plate aspect ratio and boundary conditions on the nonlinear responses of CNTR-FG laminated plates. Moreover, the effects of the number of layers and lamination angle are also investigated.

Free vibration analysis of FG-CNT reinforced composite straight-sided quadrilateral plates resting on elastic foundations using the IMLS-Ritz method

The vibration behavior was investigated of thin-to-moderately thick functionally graded carbon nanotube (FG-CNT) reinforced composite quadrilateral plates resting on elastic foundations. In the study, transverse shear and rotatory inertia were incorporated through first-order shear deformation theory. The improved moving least-squares-Ritz method was employed to derive the eigenvalue equation of the plate vibration. The study examined the effects of the elastic Winkler medium, CNT ratios, distributions of CNTs, boundary conditions, side angles, thickness-to-width ratios, and the relative plate aspect ratios on the vibration response of the FG-CNT reinforced composite plates. A set of vibration frequencies and mode shapes for the FG-CNT reinforced composite quadrilateral plates is presented. Additionally, a comprehensive parametric study and vivid mode shape plots demonstrate details of the vibration spectrum of the FG-CNT reinforced composite plates.