The Young's modulus of high-aspect-ratio carbon/carbon nanotube composite microcantilevers by experimental and modeling validation

2015 ◽  
Vol 106 (11) ◽  
pp. 111908 ◽  
Author(s):  
Peng Zhou ◽  
Xiao Yang ◽  
Liang He ◽  
Zhimeng Hao ◽  
Wen Luo ◽  
...  
e-Polymers ◽  
2011 ◽  
Vol 11 (1) ◽  
Author(s):  
Vadoud Molajavadi ◽  
Hamid Garmabi

AbstractThe Halpin-Tsai equations were used for the composites with low level content of reinforcements, which contain lamellar shape, high modulus and high aspect ratio. These characteristics of reinforcements were taken into consideration to simplify the Halpin-Tsai equations. The effect of different parameters on the longitudinal Young’s modulus of well aligned polymer/clay nanocomposites was investigated for both exfoliated and intercalated microstructures. It was shown that the applied simplification had negligible effect on the prediction of the Halpin-Tsai model. For the intercalated structures with a high number of platelets per stack (n), increase in the gallery spacing did not influence the predicted modulus values. In an intercalated structure, the surface area of a stack, as the interface of fillermatrix, is n times lower than that of the exfoliated state. By considering the effect of the degree of exfoliation in the proposed model, a new equation was developed to predict the modulus enhancement in the nanocomposites filled with Montmorillonite (MMT). The theoretical predictions were supported by the experimental results.


2021 ◽  
Vol 25 (4) ◽  
pp. 114-125
Author(s):  
Qusay W. Ahmed ◽  
◽  
Dhia A. Alazawi ◽  
Hussein B. Mohammed ◽  
◽  
...  

A three-dimensional finite element (FE) model for single-walled carbon nanotubes with armchair and zigzag shapes is proposed in this paper (SWCNTs). Nodes are positioned at the locations of carbon atoms to design the FE models. And three-dimensional elastic beam components are used to model the bonds between them. The effect of the diameter length/diameter ratio on the diameter length/diameter ratio, cross sectional aspect ratio and number of elements on the Young’s modulus of SWCNTs has been considered herein. From the conducted experiments it can be observed that, the larger tube diameter can lead to higher Young’s modulus for carbon nanotubes. Such that, maximum elastic modulus for the armchair and the zigzag models has be obtained to be 1.0285TPa and 1.0396TPa when the diameters for the armchair and the zigzag models were 2.034nm and 1.957nm respectively. Increasing the length/diameter ratio has led the Young’s modulus to be increased for armchair and zigzag models such that its values can reach 1.0451TPa and 1.0191TPa respectively. The cross sectional aspect ratio of SWCNTs showed an inversely proportional effect on the elastic modulus in this work. As a result of rising the cross sectional aspect ratio to be2, the Young's modulus for armchair and zigzag models has decreased to 0.7991TPa and 0.8873TPa, accordingly. The change in geometry has been observed to be a defect and it is in general can decrease the modulus of elasticity. The number of elements in the armchair model considered as prominent factor that increases the young’s modulus to be 1.0280TPa when the number of element is 10836. In zigzag model, the number of element has no effect on the elastic modulus since the number of nodes that exposed to the applied load is fixed in this case. The findings showed that the proposed FE model may be useful for studying carbon nanotube mechanical action in the future.


Materials ◽  
2020 ◽  
Vol 13 (17) ◽  
pp. 3749
Author(s):  
Jianjun Gao ◽  
Jian Luo ◽  
Haibin Geng ◽  
Kai Cui ◽  
Zhilong Zhao ◽  
...  

High aspect ratio tungsten nanowires have been prepared by selective dissolution of Nickel-aluminum-tungsten (NiAl−W) alloys which were directionally solidified at growth rates varying from 2 to 25 μm/s with a temperature gradient of 300 K·cm−1. Young’s modulus and electrical resistivity of tungsten nanowires were measured by metallic mask template method. The results show that the tungsten nanowires with uniform diameter and high aspect ratio are well aligned. The length of tungsten nanowires increases with prolongation of etching time, and their length reaches 300 μm at 14 h. Young’s modulus of tungsten nanowires is estimated by Hertz and Sneddon models. The Sneddon model is proper for estimating the Young’s modulus, and the value of calculating Young’s modulus are 260–460 GPa which approach the value of bulk tungsten. The resistivity of tungsten nanowires is measured and fitted with Fuchs−Sondheimer (FS) + Mayadas−Shatzkes (MS) model. The fitting results show that the specific resistivity of W nanowires is a litter bigger than the bulk W, and its value decreases with decreasing diameter.


Lab on a Chip ◽  
2011 ◽  
Vol 11 (10) ◽  
pp. 1831 ◽  
Author(s):  
Davor Copic ◽  
Sei Jin Park ◽  
Sameh Tawfick ◽  
Michael F. L. De Volder ◽  
A. John Hart

Author(s):  
Ping-Hei Chen ◽  
Cheng-Hao Yang ◽  
Chien-Ying Tsai ◽  
Tien-Li Chang ◽  
Wei-Cheng Hsu ◽  
...  

2021 ◽  
Author(s):  
Hui Cao ◽  
Wenke Chen ◽  
Zhiyuan Rui ◽  
Changfeng Yan

Abstract Metal nanomaterials exhibit excellent mechanical properties compared with corresponding bulk materials and have potential applications in various areas. Despite a number of studies of the size effect on Cu nanowires mechanical properties with square cross-sectional, investigations of them in rectangular cross-sectional with various sizes at constant volume are rare, and lack of multifactor coupling effect on mechanical properties and quantitative investigation. In this work, the dependence of mechanical properties and deformation mechanisms of Cu nanowires/nanoplates under tension on cross-sessional area, aspect ratio of cross-sectional coupled with orientation were investigated using molecular dynamics simulations and the semi-empirical expressions related to mechanical properties were proposed. The simulation results show that the Young’s modulus and the yield stress sharply increase with the aspect ratio except for the <110>{110}{001} Cu nanowires/nanoplates at the same cross-sectional area. And the Young’s modulus increases while the yield stress decreases with the cross-sectional area of Cu nanowires. However, both of them increase with the cross-sectional area of Cu nanoplates. Besides, the Young’s modulus increases with the cross-sectional area at all the orientations. The yield stress shows a mildly downward trend except for the <111> Cu nanowires with increased cross-sectional area. For the Cu nanowires with a small cross-sectional area, the surface force increases with the aspect ratio. In contrast, it decreases with the aspect ratio increase at a large cross-sectional area. At the cross-sectional area of 13.068 nm2, the surface force decreases with the aspect ratio of the <110> Cu nanowires while it increases at other orientations. The surface force is a linearly decreasing function of the cross-sectional area at different orientations. Quantitative studies show that Young’s modulus and yield stress to the aspect ratio of the Cu nanowires satisfy exponent relationship. In addition, the main deformation mechanism of Cu nanowires is the nucleation and propagation of partial dislocations while it is the twinning-dominated reorientation for Cu nanoplates.


Author(s):  
Mohsen Motamedi ◽  
AH Naghdi ◽  
SK Jalali

Composite materials have become popular because of high mechanical properties and lightweight. Aluminum/carbon nanotube is one of the most important metal composite. In this research, mechanical properties of aluminum/carbon nanotube composite were obtained using molecular dynamics simulation. Then, effect of temperature on stress–strain curve of composite was studied. The results showed by increasing temperature, the Young’s modulus of composite was decreased. More specifically increasing the temperature from 150 K to 620 K, decrease the Young’s modulus to 11.7%. The ultimate stress of composite also decreased by increasing the temperature. A continuum model of composite was presented using finite element method. The results showed the role of carbon nanotube on strengthening of composite.


2014 ◽  
Vol 1752 ◽  
pp. 59-63
Author(s):  
Junyoung Lim ◽  
Maryam Jalali ◽  
Stephen A. Campbell

ABSTRACTElectrophoretic deposition enables the rapid deposition of single wall carbon nanotube films at room temperature. An accurate, reproducible film thickness can be obtained by controlling electric field strength, suspension concentration, and time. To investigate the electrical and mechanical properties of such films, we recorded electric resistance and Young’s modulus using I-V characterization and a nanoindenter, respectively. The measured resistivity of the films varied from 2.14 × 10-3 to 7.66 × 10-3 Ω·cm, and the Young’s modulus was 4.72 to 5.67 GPa, independent of film thickness from 77 to 134 nm. These results indicated that the mechanical and electrical properties of film are comparable with previously reported methods such as layer by layer deposition even though we achieved much higher deposition rates. We also measured the film mass density which is usually unrecorded even though it is an important parameter for MEMS/NEMS device actuation. The film density was found with conventional thickness measurement and Rutherford backscattering spectrometry. It varied from 0.12 to 0.54 g/cm3 as the film thickness increased. This method could be extended to applications of CNT films for flexible electronics or high frequency RF MEMS devices.


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