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Nonlinear vibration analysis of sandwich plates with honeycomb core and graphene nanoplatelet‑reinforced face‑sheets

Mohammad‑Rezaei Bidgoli E., Arefi Mohammad

Archives of Civil and Mechanical Engineering

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2023

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Vol. 23, no. 1

art. no. e56, 2023

EN

This paper studies nonlinear vibration analysis of a graphene nanoplatelets’ composite sandwich. The core and two face-sheets of composite sandwich plate are fabricated from a honeycomb material and graphene nanoplatelet (GNP) reinforcements, respectively. Displacement field of sandwich plate is developed based on first-order shear deformation theory. Geometric nonlinearity is accounted in the constitutive relations based on von-Karman assumptions. After derivation of the governing partial differential motion equations through Hamilton’s principle, Galerkin’s approach is used to reduce them into a nonlinear equation of motion in terms of transverse defection. The nonlinear frequency is found based on linear frequency and initial conditions, analytically. The nonlinear-to-linear frequency ratio is computed based on significant input parameters of honeycomb structure and graphene nanoplatelets such as thickness-to-length and thickness-to-height ratios, angle of honeycomb, various distribution, weigh fraction and geometric characteristics of graphene nanoplatelets. Before presentation of full numerical results, the comprehensive comparative study is presented for verifcation of the derivation and solution method.

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Enhanced thermal conductivity of graphene nanoplatelets epoxy composites

Jarosinski L., Rybak A., Gaska K., Kmita G., Porebska R., Kapusta C.

Materials Science Poland

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2017

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Vol. 35, No. 2

382--389

EN

Efficient heat dissipation from modern electronic devices is a key issue for their proper performance. An important role in the assembly of electronic devices is played by polymers, due to their simple application and easiness of processing. The thermal conductivity of pure polymers is relatively low and addition of thermally conductive particles into polymer matrix is the method to enhance the overall thermal conductivity of the composite. The aim of the presented work is to examine a possibility of increasing the thermal conductivity of the filled epoxy resin systems, applicable for electrical insulation, by the use of composites filled with graphene nanoplatelets. It is remarkable that the addition of only 4 wt.% of graphene could lead to 132 % increase in thermal conductivity. In this study, several new aspects of graphene composites such as sedimentation effects or temperature dependence of thermal conductivity have been presented. The thermal conductivity results were also compared with the newest model. The obtained results show potential for application of the graphene nanocomposites for electrical insulation with enhanced thermal conductivity. This paper also presents and discusses the unique temperature dependencies of thermal conductivity in a wide temperature range, significant for full understanding thermal transport mechanisms.

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Polyamide 1010/Polythioamide Blend Reinforced with Graphene Nanoplatelet for Automotive Part Application

Kausar A.

Advances in Materials Science

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2017

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Vol. 17, nr 3(53)

24--36

EN

Novel polythioamide (PTA) was prepared and blended with polyamide 1010 (PA1010). Based on morphology, molecular weight, polydispersity index, thermal, and shear stress behavior, PA1010/PTA (90:10) blend was opted as matrix for graphene nanoplatelet (GNP) reinforcement. Inclusion of functional GNP resulted in crumpled gyroid morphology. T0 (502°C) of PA1010/PTA/GNP was increased by 145°C than unfilled blend (357°C). Limiting oxygen index measurement indicated better non-flammability of PA1010/PTA/GNP1-3 nanocomposites (53-55%) relative to PA1010/PTA1-3 (41-48%). PA1010/PTA/GNP1-3 also attained V-0 rating in UL94. Furthermore, PA1010/PTA/GNP3 nanocomposite revealed optimum tensile strength (40 MPa), impact strength (1.9 MPa), and flexural modulus (1373 MPa) to manufacture automotive part.

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Thermoplastic elastomers containing 2D nanofillers: montmorillonite, graphene nanoplatelets and oxidized graphene platelets

Paszkiewicz S., Pawelec I., Szymczyk A., Rosłaniec Z.

Polish Journal of Chemical Technology

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2015

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Vol. 17, nr 4

74--81

EN

This paper presents a comparative study on which type of platelets nanofiller, organic or inorganic, will affect the properties of thermoplastic elastomer matrix in the stronger manner. Therefore, poly(trimethylene terephthalate-block-poly(tetramethylene oxide) copolymer (PTT-PTMO) based nanocomposites with 0.5 wt.% of clay (MMT), graphene nanoplatelets (GNP) and graphene oxide (GO) have been prepared by in situ polymerization. The structure of the nanocomposites was characterized by transmission electron microscopy (TEM) in order to present good dispersion without large aggregates. It was indicated that PTT-PTMO/GNP composite shows the highest crystallization temperature. Unlike the addition of GNP and GO, the introduction of MMT does not have great effect on the glass transition temperature of PTMO-rich soft phase. An addition of all three types of nanoplatelets in the nanocomposites caused the enhancement in tensile modulus and yield stress. Additionally, the cyclic tensile tests showed that prepared nanocomposites have values of permanent set slightly higher than neat PTT-PTMO.