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Volume 5, Number 6, November 2018

Mechanical buckling of a rectangular functionally graded plate is obtained in the current paper using a refined higher-order shear and normal deformation theory. The impact of transverse normal strain is considered. The material properties are microscopically inhomogeneous and vary continuously based on a power law form in spatial direction. Navier\'s procedure is applied to examine the mechanical buckling behavior of a simply supported FG plate. The mechanical critical buckling subjected to uniaxial and biaxial compression loads are determined. The numerical investigation are compared with the numerical results in the literature. The influences of geometric parameters, power law index and different loading conditions on the critical buckling are studied.

Key Words
functionally graded plates; a refined higher-order normal and shear deformation theory; Navier\'s procedure; mechanical buckling analysis

A.M. Zenkour and M.H. Aljadani: Department of Mathematics, Faculty of Science, King Abdulaziz University, Jeddah 21589, Saudi Arabia
A.M. Zenkour: Department of Mathematics, Faculty of Science, Kafrelsheikh University, Kafrelsheikh 33516, Egypt
M.H. Aljadani: Department of Mathematics, Jamoum University College, Umm Al-Qura University, Makkah 21421, Saudi

The present paper focuses on the development of a model for simulating the thermoelectric behavior of CNTs/CFRP Organic Matrix Composite (OMC) laminates for aeronautical applications. The model is developed within the framework of the thermodynamics of irreversible processes and implemented into commercial ABAQUS Finite Element software and validated by comparison with experimental thermoelectric tests on two types of composites materials, namely Type A with Carbon Nanotubes (CNT) and Type B without CNT. A simplified model, neglecting heat conduction, is also developed for simplifying the identification process. The model is then applied for FEM numerical simulation of the thermoelectric response of aircraft panel structures subjected to electrical loads, in order to discuss the potential danger coming from electrical solicitations. The structural simulations are performed on quasi-isotropic stacking sequences (QI) [45/-45/90/0]s using composite materials of type A and type B and compared with those obtained on plates made of metallic material (aluminum). For both tested cases-transit of electric current of intermediate intensity (9A) and electrical loading on panels made of composite material-higher heating intensity is observed in composites materials with respect to the corresponding metallic ones.

Key Words
CNTs/CFRP laminates; thermoelectric behavior; numerical simulations, temperature field

Yueguo Lin: Department of Design and Manufacture of Aircrafts, Civil Aviation University of China, CAUC, 2898, Road
Jinbei, District Dongli, 300300 Tianjin, China
Marie Christine Lafarie-Frenot, Marco Gigliotti: Institut Pprime, CNRS – ENSMA – Université de Poitiers, Département Physique et Mécanique de Matériaux,
ENSMA – Téléport 2 – 1, Avenue Clément Ader, BP 40109, 86961 Futuroscope Chasseneuil Cedex, France
Jinbo Bai: CentraleSupélec, Université Paris-Saclay 3 rue Joliot-Curie, 91190 Gif-sur-Yvette, France

This work has the objective to analyze multibody mechanisms of inflatable structures for manned space applications. The focus is on the evaluation of the main characteristics of MaxFlex, a new module of MSC Adams including the effect of nonlinear flexible bodies. MaxFlex integrates the nonlinear Finite Element Analysis (FEA) of Nastran-SOL400-and the Adams multibody capabilities in one unique solver, providing an improvement concerning the concept and technology based on the co-simulation among solvers. MaxFlex converts the equations of motion of the nonlinear FEA into phase-space form and discretizes them according to the multibody system integrator framework. The numerical results deal with an inflatable manned space module having rigid components and a flexible coating made of Kevlar. This paper is a preliminary assessment of the computational capabilities of the software and does not provide realistic guidelines for the actual design of the structure. The analysis leads to some recommendations related to the main issues to consider in a nonlinear simulation including both rigid and flexible components. The results underline the importance of realistic deployment times and applied forces. Also, a proper structural modeling is necessary, but can lead to excessive computational overheads.

Key Words
multibody; MSC Adams MaxFlex; nonlinear; inflatable structures

Marco Petrolo, Giorgio Governale and Erasmo Carrera: MUL2 Group, Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129, Torino, Italy
Daniele Catelani: MSC Software srl, Via Santa Teresa 12, 10121 Torino, Italy

Bending, buckling and free vibration responses of functionally graded (FG) higher-order beams resting on two parameter (Winkler-Pasternak) elastic foundation are studied using a new inverse hyperbolic beam theory. The material properties of the beam are graded along the thickness direction according to the power-law distribution. In the present theory, the axial displacement accounts for an inverse hyperbolic distribution, and the transverse shear stress satisfies the traction-free boundary conditions on the top and bottom surfaces of the beams. Hamilton\'s principle is employed to derive the governing equations of motion. Navier type analytical solutions are obtained for the bending, bucking and vibration problems. Numerical results are obtained to investigate the effects of power-law index, length-to-thickness ratio and foundation parameter on the displacements, stresses, critical buckling loads and frequencies. Numerical results by using parabolic beam theory of Reddy and first-order beam theory of Timoshenko are specially generated for comparison of present results and found in excellent agreement with each other.

Key Words
inverse hyperbolic beam theory; FG beam; displacements; stresses; critical buckling load; frequencies, Winkler-Pasternak elastic foundation

Atteshamuddin S. Sayyad: Department of Civil Engineering, SRES\'s Sanjivani College of Engineering, Savitribai Phule Pune University,
Kopargaon-423601, Maharashtra, India
Yuwaraj M. Ghugal: Department of Applied Mechanics, Government Engineering College, Karad-415124, Maharashtra, India

In this paper the hygro-thermo-mechanical vibration and buckling behavior of embedded FG nanoplates are investigated. The Eringen\'s and Gurtin-Murdoch theories are applied to study the small scale and surface effects on frequencies and critical buckling loads. The effective material properties are modeled using Mori-Tanaka homogenization scheme. On the base of RPT and HSDPT plate theories, the Hamilton\' s principle is employed to derive governing equations. Using iterative and GDQ methods the governing equations are solved and the influence of different parameters on natural frequencies and critical buckling loads are studied.

Key Words
nanomechanics; rectangular plate; hygro-thermo-mechanical; surface effect; generalized differential quadrature method; high shear deformation plate theory; thermal loading; elastic medium; nonlocal; neutral axis

Department of Mechanical Engineering, Faculty of Engineering, Imam Khomeini International University,

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