scholarly journals FEM micromechanical modeling of nanocomposites with carbon nanotubes

2021 ◽  
Vol 60 (1) ◽  
pp. 342-351
Author(s):  
Małgorzata Chwał ◽  
Aleksander Muc
Keyword(s):  
Mechanical Properties ◽  
Elastic Properties ◽  
Fem Analysis ◽  
Micromechanical Modeling ◽  
Elastic Behavior ◽  
Material Constants ◽  
Numerical Predictions ◽  
Micromechanical Models ◽  
The Impact

Abstract Mechanical properties of carbon nanotube (CNT)-based nanocomposites are broadly discussed in the literature. The influence of CNT arrangements on the elastic properties of nanocomposites based on the finite-element method (FEM) and representative volume element (RVE) approach is presented here. This study is an application of RVE modeling in the characterization of elastic behavior of CNT polymer nanocomposites. Our main contribution is the analysis of the impact of a nanotube arrangement on the elastic properties of nanocomposite to comprehensively determine the material constants. While most of the articles are focused on one distribution, not all material constants are determined. Our FEM analysis is compared with micromechanical models and other results from the literature. The current work shows that nanotube arrangements lead to different results of elastic properties. The analytical micromechanical models are consistent with the numerical results only for axial Young’s modulus and Poisson’s ratio, whereas other elastic constants are lower than the numerical predictions. The results of these studies indicate that FEM can predict nanocomposite mechanical properties with good accuracy. This article is helpful and useful to comprehensively understand the influence of CNT arrangements on the elastic properties of nanocomposites.

Estimation of Mechanical Properties of Al/Cu Compound Layer Formed by Impact Welding

2005 ◽  
Vol 502 ◽  
pp. 455-460 ◽  
Author(s):  
Hidefumi Date ◽  
Masatoshi Futakawa ◽  
Masaaki Naka
Keyword(s):  
Mechanical Properties ◽  
Numerical Simulation ◽  
Tensile Test ◽  
Strain Curve ◽  
Fem Analysis ◽  
Compound Layer ◽  
Joint Interface ◽  
Material Constants ◽  
Impact Welding ◽  
The Impact

The impact welding of aluminum onto copper was carried out using a gas gun and the mechanical properties of Al/Cu joint were investigated by tensile tests and micro hardness indentation tests. The strength measured by tensile test decreased with increasing of the impact velocity. The results of the tensile test suggested that it was necessary to make a microscopic survey of the joint interface. Then, the inverse analysis with FEM analysis was applied to the load and depth curves measured by the indentation technique to identify the material constants in the constitutive equations of aluminum, copper and the compound layer. In addition, the numerical simulation for the tensile test was carried out using the identified material constants of aluminum, copper and the compound layer. The nominal stress-strain curve of the compound layer obtained by the numerical simulation showed the typical feature of brittle material. The ultimate tensile stress of the compound layer was about 1.2 GPa and ten times larger than that of aluminum. It was concluded that the bonding strength of Al/Cu joint was dependent on the integrity of the compound layer.

scholarly journals Development of Green Insulation Boards from Kenaf Fibres Part 1: Development and Characterization of Mechanical Properties

2011 ◽  
Vol 462-463 ◽  
pp. 1343-1348
Author(s):  
Sameer Adnan Ibraheem ◽  
Aidy Ali ◽  
Abdan Khalina
Keyword(s):  
Mechanical Properties ◽  
Elastic Properties ◽  
Optimal Performance ◽  
Fibre Content ◽  
Kenaf Fibre ◽  
Fourth Type ◽  
Kenaf Fibres

The purpose of this study was to develop effective green insulation boards fabricated from polyurethane (PU) reinforced with Kenaf fibres. Biocomposites having three different weight contents (40/60, 50/50 and 60/40 Kenaf / PU weight %) were manufactured. A fourth type was made from 60/40 NaOH-treated Kenaf / PU weight %. The results show that the elastic properties increased with Kenaf fibre content. The optimal performance was observed at a weight of 50% Kenaf fibres. In addition, kenaf fibres treated with NaOH exhibited significantly improved mechanical properties.

scholarly journals Imaging-Based Biomarkers: Characterization of Post-Kawasaki Vasculitis in Infants and Hypertension Phenotype in Rat Model

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
Roch Listz Maurice ◽  
Nagib Dahdah ◽  
Johanne Tremblay
Keyword(s):  
Mechanical Properties ◽  
Arterial Wall ◽  
Turning Point ◽  
Aortic Wall ◽  
Brown Norway ◽  
Carotid Stiffness ◽  
Old Rats ◽  
The Impact

Background. Investigating the mechanical properties of the arteries is essential in cardiovascular diseases. Recent imaging modalities allow mapping mechanical properties within the arterial wall.Aims. We report the potential ofimaging-based biomarker(ImBioMark) to investigate the effect of aging on the rat. We also present preliminary data with ImBioMark characterizing vascular sequelae of Kawasaki disease (KD) in young humans.Methods. We investigatedin vivothe effect of aging on male Brown Norway (BN) rats' (n=5) carotid stiffness. In a second experiment, the impact of KD on the ascending aorta (AA) was examined in KD children (n=2) aged 13 ± 1.41 years old compared to KD-free children (n=5) aged 13.13 ± 0.18 years old.Results. The stiffness of BN's carotid artery was three times stiffer in the old rats, with a turning point at 40 weeks old (P=0.001). KD had a very significant impact on the AA stiffness with strain estimates of 2.39 ± 0.51% versus 4.24 ± 0.65% in controls (P<0.001).Conclusion. ImBioMark phenotypes hypertension in rat models noninvasivelyin vivowithout resorting to euthanasia. Quantifying aortic wall remodeling is also feasible in humans. Future investigations target human cardiovascular disease.

Analysis of the Scatter of the Elastic Properties in Conventionally Cast Nickel Base Superalloys: Quantification, Modeling and Evaluation of the Impact on Gas Turbine Blade Design

2014 ◽  
Author(s):  
Andrea Riva ◽  
Andrea Bessone
Keyword(s):  
Gas Turbine ◽  
Young’S Modulus ◽  
Elastic Properties ◽  
Young's Modulus ◽  
Turbine Blades ◽  
Mode Shapes ◽  
Elastic Behavior ◽  
Nickel Base Superalloys ◽  
Nickel Base ◽  
The Impact

Cast nickel-base superalloys elastic properties have a very large scatter, mainly because of the coarse grain microstructure and in-grain anisotropy. This high dispersion must be taken into account in the design of gas turbine blades, in particular when evaluating phenomena directly linked to the elastic behavior, such as blades vibration. This source of elastic properties scatter becomes even more important on specimens for material characterization because of their inferior size, which entails a lesser number of grains (i.e. a larger scatter). In this paper a model aimed to quantify such scatter is proposed. The performances of the model in predicting the standard deviation of the Young’s modulus (and consequently of the eigenfrequencies) are also shown, both for tested specimens and blades excited on clamps. Finally, a sensitivity FEM modal analysis is performed in order to evaluate how the elastic property dispersion might affect the blade eigenfrequencies and the relative mode shapes, with particular emphasis on the case of a specific region of a geometrically complex component affected by an anomalous Young’s modulus. Besides, the influence of the blade mass is evaluated through both experimental clamp impact tests and FEM analyses. The effect on blades of such source of scatter is then compared to the effect of the elastic properties dispersion. ANSYS program has been used for the simulations.

Characterization of Mechanical and Thermal Properties of PP/Mineral Composites

2014 ◽  
Vol 1025-1026 ◽  
pp. 241-245 ◽  
Author(s):  
Ľudmila Dulebová ◽  
Emil Spišák ◽  
Branislav Duleba ◽  
František Greškovič ◽  
Tomasz Garbacz
Keyword(s):  
Mechanical Properties ◽  
Thermal Analysis ◽  
Mechanical And Thermal Properties ◽  
Screw Extruder ◽  
Twin Screw ◽  
Pp Composites ◽  
Mineral Fillers ◽  
The Impact ◽  
Properties Of Composites

The paper presents the impact of the use of fillers on the mechanical properties of composites with polymeric matrix from polypropylene (PP). Two main types of mineral fillers - talc and calcium carbonate - were used for experiments. PP composites of different percentage filler in matrix PP were compounded with twin-screw extruder and then injection molding. Properties of composites were investigated by tensile test and thermal analysis. Tensile strength was performed to determine and compare the mechanical properties of the unfilled PP and filled PP with various percentages of fillers. Thermal analysis by thermogravimetric was performed on the tested materials - weight loss, glass transition temperature, thermal decomposition, melting temperature.

scholarly journals Aluminum Matrix Composites with Weak Particle Matrix Interfaces: Effective Elastic Properties Investigated Using Micromechanical Modeling

Materials ◽  
2021 ◽  
Vol 14 (20) ◽  
pp. 6083
Author(s):  
Aharon Farkash ◽  
Brigit Mittelman ◽  
Shmuel Hayun ◽  
Elad Priel
Keyword(s):  
Elastic Properties ◽  
Effective Properties ◽  
Aluminum Matrix ◽  
Unit Cell ◽  
Micromechanical Modeling ◽  
Aluminum Matrix Composites ◽  
Matrix Composites ◽  
Element Analysis ◽  
Effective Elastic Properties ◽  
The Impact

The impact of weak particle-matrix interfaces in aluminum matrix composites (AMCs) on effective elastic properties was studied using micromechanical finite-element analysis. Both simplified unit cell representations (i.e., representative area or volume elements) and “real” microstructure-based unit cells were considered. It is demonstrated that a 2D unit cell representation provides accurate effective properties only for strong particle-matrix bond conditions, and underpredicts the effective properties (compared to 3D unit cell computations) for weak interfaces. The computations based on real microstructure of an Al–TiB2 composite fabricated using spark plasma sintering (SPS) show that, for weak interfaces, the effective elastic properties under tension are different from those obtained under compression. Computations show that differences are the result of the local stress and strain fields, and contact mechanics between particles and the matrix. Preliminary measurements of the effective elastic properties using the ultrasonic pulse-echo technique and compression experiments support the trends observed in computational analysis.

Elastic response of Carbon Black reinforced polyester based composites using micromechanical models: Role of interphase

2022 ◽  
pp. 239779142110701
Author(s):  
Mehdi Karevan
Keyword(s):  
Carbon Black ◽  
Thermal Studies ◽  
Elastic Response ◽  
Elastic Behavior ◽  
Analytical Prediction ◽  
Morphological Studies ◽  
Micromechanical Models ◽  
The Impact ◽  
Carbon Based

Carbon-based reinforcements have been widely reported in improving mechanical properties of polymers. However, still few studies exist on the incorporation of the interphase as a result of the interfacial interactions into analytical prediction tools. To better understand the effect of interfacial interphase, this study compares and correlates the experimental mechanical response of polyester based composites filled with carbon black (CB) with the elastic behavior obtained from the micromechanical models. Mold cast composites of polyester reinforced with 0 wt%–10 wt% of CB were fabricated. To determine the length of cooperative rearranging region (CRR) as a measure of the interphase, thermal studies focusing on the variations in the specific heat capacity or the relaxation strength of the composites around the glass transition temperature ( Tg) range were performed using a thermodynamical model. Micromechanical models such as the Halpin-Tsai and Tandon-Weng were used to determine the Young’s modulus with respect to the CB wt% and diameter as well as the interphase thickness and modulus. The results exhibited the sensitivity of the models to the existence of the interphase as a secondary mechanism, which was correlated to the cross-link density and interfacial bonding. The impact results showed the decrease in the impact resistance upon the addition of higher filler loadings ascribed to the destroyed bonding at the interface and CBs agglomeration confirmed by morphological studies. The research results can be further utilized in the explanation of the changes in the elastic response of carbon-based reinforced thermosetting composites emphasizing the key role of interphase.

scholarly journals Elastic Properties of a Polyimide Film Determined by Brillouin Scattering and Mechanical Techniques

1993 ◽  
Vol 308 ◽  
Author(s):  
R. Sai Kumar ◽  
Ivan K. Schuller ◽  
Sudha S. Kumar ◽  
A. Fartash ◽  
M. Grimsditch
Keyword(s):  
Elastic Properties ◽  
Brillouin Scattering ◽  
Direct Determination ◽  
Polyimide Film ◽  
Complete Characterization ◽  
Elastic Behavior ◽  
Complete Determination ◽  
Vibrating Membrane

ABSTRACTWe discuss here the complete determination of the elastic properties of a polyimide film using two experimental techniques. One technique employs the polymer film as a vibrating membrane and allows a direct determination of the ’macroscopic’ biaxial modulus. Brillouin scattering, which measures the elastic properties on a ∼ 100 μ scale, allows for a complete characterization of the elastic behavior. The results obtained by the two techniques are in agreement within the reported error bars.

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