Surface effect on size dependent Young’s modulus of nanowires: Exponentially decreased surface elasticity model

2022 ◽  
Vol 307 ◽  
pp. 131001
Author(s):  
Jiangang Li ◽  
Xiao Lei ◽  
Jianhua Ding ◽  
Zhixiang Gao ◽  
Hua Wang ◽  
...  
Keyword(s):  
Young’S Modulus ◽  
Surface Effect ◽  
Young's Modulus ◽  
Surface Elasticity ◽  
Size Dependent

Size-Dependent Elastic Behavior of Silicon Nanofilms: Molecular Dynamics Study

2009 ◽  
Author(s):  
Hamed Sadeghian ◽  
Johannes F. L. Goosen ◽  
Andre Bossche ◽  
Barend J. Thijsse ◽  
Fred van Keulen
Keyword(s):  
Molecular Dynamics ◽  
Surface Energy ◽  
Young’S Modulus ◽  
Size Dependence ◽  
Young's Modulus ◽  
Surface Elasticity ◽  
Elastic Behavior ◽  
Continuum Approach ◽  
Size Dependent ◽  
Embedded Atom

In this paper, the size-dependence of the elastic behavior of silicon nanofilms terminated by (100) surfaces is studied by means of molecular dynamics with the modified embedded atom method (MEAM). The results indicate that the (100) surfaces undergo 2×1 reconstruction, which significantly influences the mechanical properties of ultra-thin films. The simulations are carried out at room temperature and structural relaxation is performed. The effective Young’s modulus, in extensional mode, is determined for different thicknesses. The surface energy, surface stress and surface elasticity of layers near the surfaces (non-bulk layers) in the thin silicon films are obtained. The surface properties of nanofilms of a few layers are shown to deviate from thicker films, suggesting a size-dependence of surface parameters and, especially, surface energy. Finally, the results of a recently developed semi-continuum approach are compared with the molecular dynamics results. Below 3 nm, there is a difference between the effective Young’s modulus, calculated by the semi-continuum approach and that provided by MD, suggesting that the continuum approach can no longer provide accurate results.

scholarly journals Effect of Nanopores on Mechanical Properties of the Shape Memory Alloy

Micromachines ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 529
Author(s):  
Chunzhi Du ◽  
Zhifan Li ◽  
Bingfei Liu
Keyword(s):  
Mechanical Properties ◽  
Constitutive Model ◽  
Shape Memory ◽  
Young’S Modulus ◽  
Residual Strain ◽  
Surface Effect ◽  
Young's Modulus ◽  
Strain Curve ◽  
Stress Strain ◽  
Strength Limit

Nanoporous Shape Memory Alloys (SMA) are widely used in aerospace, military industry, medical and health and other fields. More and more attention has been paid to its mechanical properties. In particular, when the size of the pores is reduced to the nanometer level, the effect of the surface effect of the nanoporous material on the mechanical properties of the SMA will increase sharply, and the residual strain of the SMA material will change with the nanoporosity. In this work, the expression of Young’s modulus of nanopore SMA considering surface effects is first derived, which is a function of nanoporosity and nanopore size. Based on the obtained Young’s modulus, a constitutive model of nanoporous SMA considering residual strain is established. Then, the stress–strain curve of dense SMA based on the new constitutive model is drawn by numerical method. The results are in good agreement with the simulation results in the published literature. Finally, the stress-strain curves of SMA with different nanoporosities are drawn, and it is concluded that the Young’s modulus and strength limit decrease with the increase of nanoporosity.

Size- and temperature-dependent Young's modulus and size-dependent thermal expansion coefficient of thin films

2016 ◽  
Vol 18 (31) ◽  
pp. 21508-21517 ◽  
Author(s):  
Xiao-Ye Zhou ◽  
Bao-Ling Huang ◽  
Tong-Yi Zhang
Keyword(s):  
Thin Films ◽  
Thermal Expansion ◽  
Young’S Modulus ◽  
Thermal Expansion Coefficient ◽  
Expansion Coefficient ◽  
Material Properties ◽  
Essential Role ◽  
Young's Modulus ◽  
Temperature Dependent ◽  
Size Dependent

Surfaces of nanomaterials play an essential role in size-dependent material properties.

Size-Dependent Young's Modulus of the FCC Metallic Films

2012 ◽  
Vol 499 ◽  
pp. 76-79
Author(s):  
Ming Li ◽  
G.H. Su
Keyword(s):  
Young’S Modulus ◽  
Elastic Deformation ◽  
Young's Modulus ◽  
Energy Curve ◽  
Fundamental Parameter ◽  
Deformation Capacity ◽  
Metallic Films ◽  
Size Dependent ◽  
Simulation Results ◽  
Young Equation

Young's modulus is one of the most fundamental parameter to depict the elasticity of a given material. It determines the basic elastic deformation capacity of a structure under a bear load. When the diameter of nanocrystals is in the scale of several nanometers, the Young's modulus is quite different from that of bulk. In order to determine elastic deformation capacity of nanocrystals, it is necessary to study the size dependent Young's modulus. Based on above consideration, a simple thermodynamic model is developed for size dependent Young's modulus of nanocrystals according to the “universal” binding energy curve and Laplace-Young equation. According to this model, the Young's modulus of several FCC metallic films is predicted and the Young's modulus increases with the size reduction. The prediction is agreed with computer simulation results.

Modeling of Piezoelectric Bimorph Nano-Actuators With Surface Effects

2013 ◽  
Vol 80 (6) ◽  
Author(s):  
Chunli Zhang ◽  
Chuanzeng Zhang ◽  
Weiqiu Chen
Keyword(s):  
Effective Properties ◽  
Surface Effect ◽  
Surface Elasticity ◽  
Driving Voltage ◽  
Two Dimensional ◽  
Piezoelectric Bimorph ◽  
Simply Supported ◽  
Size Dependent ◽  
Spring Force ◽  
Plate Type

Two-dimensional (2D) equations of piezoelectric bimorph nano-actuators are presented which take account of the surface effect. The surface effect of the bimorph structure is treated as a surface layer with zero thickness. The influence on the plate's overall properties resulted from the surface elasticity and piezoelectricity is modeled by a spring force exerting on the boundary of the bulk core. Using the derived 2D equations, the anti-parallel piezoelectric bimorph nano-actuators of both cantilever and simply supported plate type are investigated theoretically. Numerical results show that the effective properties and the deflections of the antiparallel bimorph nano-actuators are size-dependent. The deflection at the resonant frequency achieves nearly 50 times as that under the static driving voltage.

scholarly journals Mechanical Researches on Young's Modulus of SCS Nanostructures

2009 ◽  
Vol 2009 ◽  
pp. 1-6 ◽  
Author(s):  
Qinhua Jin ◽  
Tie Li ◽  
Ping Zhou ◽  
Yuelin Wang
Keyword(s):  
Young’S Modulus ◽  
Surface Effect ◽  
Young's Modulus ◽  
Tensile Tests ◽  
Testing Methods ◽  
Bending Tests ◽  
Resonance Test ◽  
Experimental Errors ◽  
The Difference ◽  
Experimental Researches

Nanostructures of SingleCrystalSilicon (SCS) with superior electrical, mechanical, thermal, and optical properties are emerging in the development of novel nanodevices. Mechanical properties especially Young's modulus are essential in developing and utilizing such nanodevices. In this paper, experimental researches including bending tests, resonance tests, and tensile tests on Young' s modulus of nanoscaled SCS are reviewed, and their results are compared. It was found that the values ofEmeasured by different testing methods cannot match to each other. As the differences cannot be explained as experimental errors, it should be understood by taking surface effect into account. With a simplified model, we qualitatively explained the difference inEvalue measured by tensile test and by resonance test for Si nanobeams.

Size-dependent effective Young’s modulus of silicon nitride cantilevers

2009 ◽  
Vol 94 (23) ◽  
pp. 233108 ◽  
Author(s):  
Khashayar Babaei Gavan ◽  
Hidde J. R. Westra ◽  
Emile W. J. M. van der Drift ◽  
Warner J. Venstra ◽  
Herre S. J. van der Zant
Keyword(s):  
Silicon Nitride ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Size Dependent

CONTINUUM SHELL MODEL FOR BUCKLING OF ARMCHAIR CARBON NANOTUBES UNDER COMPRESSION OR TORSION

2014 ◽  
Vol 06 (01) ◽  
pp. 1450006 ◽  
Author(s):  
A. N. ROY CHOWDHURY ◽  
C. M. WANG ◽  
S. J. A. KOH
Keyword(s):  
Carbon Nanotubes ◽  
Shell Model ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Twist Angle ◽  
Md Simulations ◽  
Torsional Stiffness ◽  
Size Dependent ◽  
Bond Order Potential ◽  
Double Walled Carbon Nanotubes

Molecular dynamics (MD) simulations are performed using adaptive intermolecular reactive bond order potential to analyze single-walled and double-walled carbon nanotubes. These carbon nanotubes were analyzed for buckling under compression and under torsion. The MD simulations create a comprehensive database for the critical buckling loads/strains and critical buckling torques/twist angles for armchair SWCNTs and DWCNTs of varying diameters and lengths. Using MD results as a computational benchmark, an equivalent thick shell model of CNT is proposed, which is amenable for analysis using a commercially available software ABAQUS. Based on our MD results, an empirical equation that describes the size-dependent Young's modulus for a single-walled carbon nanotube is established. Buckling analysis of CNT under compression and under torsion are performed with the equivalent shell model using size-dependent Young's modulus, Poisson's ratio = 0.19 and shell thickness h = 0.066 nm. We show that the equivalent shell model gives good estimate of critical buckling load/strain and critical buckling torque with respect to the MD results. Variation of critical twist angle with length of CNT, predicted by the shell model is in good qualitative agreement with MD simulation. However, the equivalent shell model underestimates the critical twist angle by 30% because the continuum shell model overestimates torsional stiffness of CNT compared to an atomistic model of CNT. The equivalent shell model is less computational intensive to implement as compared with MD. Its accuracy for predicting the buckling states for long carbon nanotubes allows it to be used for moderately long CNTs under compression/torsion, in-lieu of MD simulations.

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