Wave propagation in functionally graded composite cylinders reinforced by aggregated carbon nanotube

Rasool Moradi-Dastjerdi 국제구조공학회 2016 Structural Engineering and Mechanics, An Int'l Jou Vol.57 No.3

This work reports wave propagation in the nanocomposite cylinders that reinforced by straight single-walled carbon nanotubes based on a mesh-free method. Moving least square shape functions have been used for approximation of displacement field in weak form of motion equation. The straight carbon nanotubes (CNTs) are assumed to be oriented in specific or random directions or locally aggregated into some clusters. In this simulation, an axisymmetric model is used and also the volume fractions of the CNTs and clusters are assumed to be functionally graded along the thickness. So, material properties of the carbon nanotube reinforced composite cylinders are variable and estimated based on the Eshelby-Mori-Tanaka approach. The effects of orientation, aggregation and volume fractions of the functionally graded clusters and CNTs on dynamic behavior of nanocomposite cylinders are studied. This study results show that orientation and aggregation of CNTs have significant effects on the effective stiffness and dynamic behaviors.

Dynamic analysis of functionally graded nanocomposite plates reinforced by wavy carbon nanotube

Rasool Moradi-Dastjerdi,Hamed Momeni-Khabisi 국제구조공학회 2016 Steel and Composite Structures, An International J Vol.22 No.2

In this paper, free vibration, forced vibration, resonance and stress wave propagation behavior in nanocomposite plates reinforced by wavy carbon nanotube (CNT) are studied by a mesh-free method based on first order shear deformation theory (FSDT). The plates are resting on Winkler-Pasternak elastic foundation and subjected to periodic or impact loading. The distributions of CNTs are considered functionally graded (FG) or uniform along the thickness and their mechanical properties are estimated by an extended rule of mixture. In the mesh-free analysis, moving least squares (MLS) shape functions are used for approximation of displacement field in the weak form of motion equation and the transformation method is used for imposition of essential boundary conditions. Effects of CNT distribution, volume fraction, aspect ratio and waviness, and also effects of elastic foundation coefficients, plate thickness and time depended loading are examined on the vibrational and stresses wave propagation responses of the nanocomposite plates reinforced by wavy CNT.

Thermoelastic static and vibrational behaviors of nanocomposite thick cylinders reinforced with graphene

Rasool Moradi-Dastjerdi,Kamran Behdinan 국제구조공학회 2019 Steel and Composite Structures, An International J Vol.31 No.5

Current paper deals with thermoelastic static and free vibrational behaviors of axisymmetric thick cylinders reinforced with functionally graded (FG) randomly oriented graphene subjected to internal pressure and thermal gradient loads. The heat transfer and mechanical analyses of randomly oriented graphene-reinforced nanocomposite (GRNC) cylinders are facilitated by developing a weak form mesh-free method based on moving least squares (MLS) shape functions. Furthermore, in order to estimate the material properties of GRNC with temperature dependent components, a modified Halpin-Tsai model incorporated with two efficiency parameters is utilized. It is assumed that the distributions of graphene nano-sheets are uniform and FG along the radial direction of nanocomposite cylinders. By comparing with the exact result, the accuracy of the developed method is verified. Also, the convergence of the method is successfully confirmed. Then we investigated the effects of graphene distribution and volume fraction as well as thermo-mechanical boundary conditions on the temperature distribution, static response and natural frequency of the considered FG-GRNC thick cylinders. The results disclosed that graphene distribution has significant effects on the temperature and hoop stress distributions of FG-GRNC cylinders. However, the volume fraction of graphene has stronger effect on the natural frequencies of the considered thick cylinders than its distribution.

Transient heat transfer analysis of functionally graded CNT reinforced cylinders with various boundary conditions

Rasool Moradi-Dastjerdi,Gholamhassan Payganeh 국제구조공학회 2017 Steel and Composite Structures, An International J Vol.24 No.3

In this work, transient heat transfer analysis of functionally graded (FG) carbon nanotube reinforced nanocomposite (CNTRC) cylinders with various essential and natural boundary conditions is investigated by a mesh-free method. The cylinders are subjected to thermal flux, convection environments and constant temperature faces. The material properties of the nanocomposite are estimated by an extended micro mechanical model in volume fraction form. The distribution of carbon nanotube (CNT) has a linear variation along the radial direction of axisymmetric cylinder. In the mesh-free analysis, moving least squares shape functions are used for approximation of temperature field in the weak form of heat transform equation and the transformation method is used for the imposition of essential boundary conditions. Newmark method is applied for solution time depended problem. The effects of CNT distribution pattern and volume fraction, cylinder thickness and boundary conditions are investigated on the transient temperature field of the nanocomposite cylinders.

Big data in nanocomposites: ONN approach and mesh-free method for functionally graded carbon nanotube-reinforced composites

Mostafa Jalal,Rasool Moradi-Dastjerdi,Morteza Bidram 한국CDE학회 2019 Journal of computational design and engineering Vol.6 No.2

In this paper, the concept of big data in composite materials for design purpose with focus on functionally graded carbon nanotube reinforced composites (FG-CNTRC) has been addressed through mesh-free method and an optimized neural network (ONN) approach. With this regard, mesh-free method as a robust technique was used to analyze the FG-CNTRC for vibrational frequency. The applied nanocompos-ite is made of aggregated single-walled carbon nanotubes (CNTs) that are embedded in an isotropic polymer as matrix. The material properties are estimated based on the Eshelby–Mori–Tanaka approach. Then a new multi-step approach was used to find optimized neural network for accurate modeling of the nanocomposite which can be used for later goals of optimization and design. Computational time and accuracy of various algorithms were investigated and compared for big data modeling of nanocomposite to come up with the optimal model. Comparative study of the results was carried out to examine and compare the accuracy of the developed ONN model relative to mesh-free method. Furthermore, a comprehensive parametric study was also performed to investigate the effect of geometrical dimensions, CNT distribution and volume fraction on vibrational frequency of the nanocomposite.

Thermal buckling resistance of a lightweight lead-free piezoelectric nanocomposite sandwich plate

Behdinan, Kamran,Moradi-Dastjerdi, Rasool Techno-Press 2022 Advances in nano research Vol.12 No.6

The critical buckling temperature rise of a newly proposed piezoelectrically active sandwich plate (ASP) has been investigated in this work. This structure includes a porous polymeric layer integrated between two piezoelectric nanocomposite layers. The piezoelectric material is made of a passive polymeric material that is activated by lead-free nanowires (NWs) of zinc oxide (ZnO) embedded inside the matrix. In both nanocomposite layers and porous core, functional graded (FG) patterns have been considered for the distributions of ZnO NWs and voids, respectively. By adopting a higher-order theory of plates, the governing equations of thermal buckling are obtained. This set of equations is then treated using an extended mesh-free solution. The effects of plate dimensions, porosity states, and the nanowire parameters have been investigated on the critical buckling temperature rises of the proposed lightweight ASPs with different boundary conditions. The results disclose that the use of porosities in the core and/or mixing ZnO NWs in the face sheets substantially arise the critical buckling temperatures of the newly proposed active sandwich plates.