Development of Matched Interface and Boundary Method for Buckling Analysis of Plates with Various Interfaces

Buckling problems of plates with interfaces caused by step changes in thickness, internal line supports and line hinges under uni-axial and bi-axial in-plane compressive loads are solved by using the matched interface and boundary (MIB) method. In view of buckling problems of plates, new MIB algorithms and their interpolation formulations are developed to deal with various interfaces. A number of examples are taken to examine the accuracy and convergence of the present algorithms. Numerical results are compared with the existing solutions to validate the applicability of these algorithms to the title problems. Numerical analysis shows that on the whole, MIB and its interpolation formulation are equivalent, and they are highly accurate and efficient approaches for buckling analysis of plates with various interfaces.

Vibration characteristics of functionally graded carbon nanotube reinforced composite rectangular plates on Pasternak foundation with arbitrary boundary conditions and internal line supports

This paper presents the first known vibration characteristics of moderately thick functionally graded carbon nanotube reinforced composite rectangular plates on Pasternak foundation with arbitrary boundary conditions and internal line supports on the basis of the firstorder shear deformation theory. Different distributions of single walled carbon nanotubes (SWCNTs) along the thickness are considered. Uniform and other three kinds of functionally graded distributions of carbon nanotubes along the thickness direction of plates are studied. The solutions carried out using an enhanced Ritz method mainly include the following three points: Firstly, create the Lagrange energy function by the energy principle; Secondly, as the main innovation point, the modified Fourier series are chosen as the basic functions of the admissible functions of the plates to eliminate all the relevant discontinuities of the displacements and their derivatives at the edges; Lastly, solve the natural frequencies as well as the associated mode shapes by means of the Ritz-variational energy method. In this study, the influences of the volume fraction of CNTs, distribution type of CNTs, boundary restrain parameters, location of the internal line supports, foundation coefficients on the natural frequencies and mode shapes of the FG-CNT reinforced composite rectangular plates are presented.

Frequency optimization of laminated composite plates with different intermediate line supports

This paper deals with frequency optimization of symmetrically laminated 4-layered angle-ply plates with one or two different intermediate line supports. The design objective is the maximization of the fundamental frequency and the design variable is the fiber orientation in the layers. The first order shear deformation theory and nine-node isoparametric finite element model are used for finding the natural frequencies of laminates. The modified feasible direction method is used for the optimization routine. For this purpose, a program based on FORTRAN is used. Finally, the numerical analysis is carried out to investigate the effects of location of the internal line supports, plate aspect ratios and boundary conditions on the optimal designs and the results are compared.