scholarly journals An Auxetic System Based on Interconnected Y-Elements Inspired by Islamic Geometric Patterns

Symmetry ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 865
Author(s):  
Teik-Cheng Lim
Keyword(s):  
Young’S Modulus ◽  
Young's Modulus ◽  
Limited Range ◽  
Geometrical Parameters ◽  
Full Extension ◽  
Geometric Patterns ◽  
The North ◽  
Spiral Spring ◽  
Elastically Restrained ◽  
Deformation Models

A 2D mechanical metamaterial exhibiting perfectly auxetic behavior, i.e., Poisson’s ratio of , is proposed in this paper drawing upon inspiration from an Islamic star formed by circumferential arrangement of eight squares, such as the one found at the exterior of the Ghiyathiyya Madrasa in Khargird, Iran (built 1438–1444 AD). Each unit of the metamaterial consists of eight pairs of pin-jointed Y-shaped rigid elements, whereby every pair of Y-elements is elastically restrained by a spiral spring. Upon intermediate stretching, each metamaterial unit resembles the north dome of Jameh Mosque, Iran (built 1087–1088 AD), until the attainment of the fully opened configuration, which resembles a structure in Agra, India, near the Taj Mahal. Both infinitesimal and finite deformation models of the effective Young’s modulus for the metamaterial structure were established using strain energy approach in terms of the spiral spring stiffness and geometrical parameters, with assumptions to preserve the eight-fold symmetricity of every metamaterial unit. Results indicate that the prescription of strain raises the effective Young’s modulus in an exponential manner until full extension is attained. This metamaterial is useful for applications where the overall shape of the structure must be conserved in spite of uniaxial application of load, and where deformation is permitted under limited range, which is quickly arrested as the deformation progresses.

scholarly journals Modifying the dissolved-in-water type natural gas field simulation model based on the distribution of estimated Young's modulus for the Kujukuri region, Japan

2015 ◽  
Vol 372 ◽  
pp. 417-419
Author(s):  
T. Nakagawa ◽  
R. Matsuyama ◽  
M. Adachi ◽  
S. Kuroshima ◽  
T. Ogatsu ◽  
...  
Keyword(s):  
Natural Gas ◽  
Simulation Model ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Water Type ◽  
Gas Field ◽  
The North ◽  
Chiba Prefecture ◽  
Field Simulation ◽  
Yield Value

Abstract. A simulation model, which covers the part of Southern-Kanto natural gas field in Chiba prefecture, was developed to perform studies and make predictions of land subsidence. However, because large differences between simulated and measured subsidence occurred in the northern modeled area of the gas field, the model was modified with an estimated Young's modulus distribution. This distribution was estimated by the yield value distribution and the correlation of yield value with Young's modulus. Consequently, the simulated subsidence in the north area was improved to some extent.

Investigation of Effect of Geometrical Parameters of Vertically Aligned Carbon Nanotubes on their Mechanical Properties

2014 ◽  
Vol 894 ◽  
pp. 355-359 ◽  
Author(s):  
Oleg. A. Ageev ◽  
Oleg I. Ilin ◽  
Alexei S. Kolomiytsev ◽  
Marina V. Rubashkina ◽  
Vladimir A. Smirnov ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Bending Stiffness ◽  
Geometrical Parameters ◽  
Vertically Aligned Carbon Nanotubes ◽  
Force Microscopy ◽  
Aligned Carbon Nanotubes ◽  
Vertically Aligned ◽  
Experimental Researches

In the work the results of experimental researches of geometric and mechanical parameters of vertically aligned carbon nanotubes (VACNT) by atomic force microscopy (AFM) and nanoindentation are presented. Here is also shown the influence of diameter and length of the carbon nanotube on the value of bending stiffness and Young's modulus of nanotubes. The analysis of the experimental researches shows that the magnitude of bending stiffness significantly increases with the increasing of the diameter of the nanotubes and decreases with increasing length of the CNT. Diameter and length of the carbon nanotubes also have the most significant influence on Young's modulus of CNTs. The obtained results can be used to develop the processes of formation of micro-and nanoelectronic elements based on the VACNT.

Vibration Propagation Characteristics of Binary Periodic Sandwich Panels

2012 ◽  
Vol 226-228 ◽  
pp. 172-175 ◽  
Author(s):  
Pei Pei Ge ◽  
Gui Lan Yu
Keyword(s):  
Band Gap ◽  
Young’S Modulus ◽  
Frequency Band ◽  
Vibration Isolation ◽  
Young's Modulus ◽  
Low Frequency ◽  
Sandwich Panels ◽  
Geometrical Parameters ◽  
The Finite Element Method ◽  
Steel Cylinder

By using the finite element method, the band structures of the periodic hollow cylinder sandwich panels are investigated, and the influences of the material and geometrical parameters on the band gap are discussed in detail. The results show that The Young's modulus of panel and the coated layer have the greatest influences on the band gap of binary periodic hollow steel cylinder sandwich panels. The smaller the Young's modulus, the lower the frequency band gap. The material and geometrical parameters of the core have important influences on the lower edges of the band gap. Thicker and higher hollow steel cylinder with large density is favorable to gain a wide low-frequency band gap. The work presented will provide a theoretical guidance in the vibration isolation research.

scholarly journals Estimating Young’s Modulus of Single-Walled Zirconia Nanotubes Using Nonlinear Finite Element Modeling

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Ibrahim Dauda Muhammad ◽  
Mokhtar Awang ◽  
Othman Mamat ◽  
Ku Zilati Ku Shaari
Keyword(s):  
Finite Element ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Reaction Force ◽  
Cubic Phase ◽  
Geometrical Parameters ◽  
Element Analysis ◽  
Axial Tensile ◽  
Energy Equivalence ◽  
Element Approach

The single-walled zirconia nanotube is structurally modeled and its Young’s modulus is valued by using the finite element approach. The nanotube was assumed to be a frame-like structure with bonds between atoms regarded as beam elements. The properties of the beam required for input into the finite element analysis were computed by connecting energy equivalence between molecular and continuum mechanics. Simulation was conducted by applying axial tensile strain on one end of the nanotube while the other end was fixed and the corresponding reaction force recorded to compute Young’s modulus. It was found out that Young’s modulus of zirconia nanotubes is significantly affected by some geometrical parameters such as chirality, diameter, thickness, and length. The obtained values of Young’s modulus for a certain range of diameters are in agreement with what was obtained in the few experiments that have been conducted so far. This study was conducted on the cubic phase of zirconia having armchair and zigzag configuration. The optimal diameter and thickness were obtained, which will assist in designing and fabricating bulk nanostructured components containing zirconia nanotubes for various applications.

scholarly journals Sliding Interaction for Coated Asperity with Power-Law Hardening Elastic-Plastic Coatings

Materials ◽  
2019 ◽  
Vol 12 (15) ◽  
pp. 2388
Author(s):  
Bin Zhao ◽  
Hanzhang Xu ◽  
Xiqun Lu
Keyword(s):  
Friction Coefficient ◽  
Yield Strength ◽  
Young’S Modulus ◽  
Contact Force ◽  
Young's Modulus ◽  
Contact Forces ◽  
Geometrical Parameters ◽  
Asperity Contact ◽  
Strength Ratio ◽  
Modulus Ratio

Sliding between asperities occurs inevitably in the friction pair, which affects the efficiency and reliability in both lubricated and non-lubricated conditions. In this work, the contact parameters in the coated asperity sliding process are studied, and the universal expressions of the average contact force and the friction coefficient are obtained. The effect of the interference between asperities, the material and geometrical parameters including the Young’s modulus ratio and yield strength ratio of the coating and substrate, and the hardening exponent and thickness of the coating on the average contact forces and friction coefficient is considered. It shows both normal and tangential contact forces increase with the increasing interference, increasing Young’s modulus ratio, decreasing yield strength ratio, and decreasing coating thickness; while the trend is different for the effect of the hardening exponent of the coating. The normal force increases and the tangential force decreases as the hardening exponent increases. Based on this, the influence of these parameters on the effective friction coefficient is obtained further. It reveals that the friction coefficient increases as the interference and Young’s modulus ratio enlarge and decreases as the yield strength ratio, the coating’s hardening exponent, and thickness increase. The universal expressions for the contact force and friction coefficient in the sliding process are obtained. This work might give some useful results to help choose the optimum coatings for specific substrates to reduce friction in cases where the asperity contact exists, especially in the focused field of the journal bearing in the marine engine under poor lubrication conditions.

Estimation of Cell Young’s Modulus of Adherent Cells Probed by Optical and Magnetic Tweezers: Influence of Cell Thickness and Bead Immersion

2006 ◽  
Vol 129 (4) ◽  
pp. 523-530 ◽  
Author(s):  
Alain Kamgoué ◽  
Jacques Ohayon ◽  
Philippe Tracqui
Keyword(s):  
Young’S Modulus ◽  
External Force ◽  
Elasticity Modulus ◽  
Young's Modulus ◽  
Magnetic Tweezers ◽  
Cell Stiffness ◽  
Cell Cortex ◽  
Geometrical Parameters ◽  
Adherent Cells ◽  
Cell Thickness

A precise characterization of cell elastic properties is crucial for understanding the mechanisms by which cells sense mechanical stimuli and how these factors alter cellular functions. Optical and magnetic tweezers are micromanipulation techniques which are widely used for quantifying the stiffness of adherent cells from their response to an external force applied on a bead partially embedded within the cell cortex. However, the relationships between imposed external force and resulting bead translation or rotation obtained from these experimental techniques only characterize the apparent cell stiffness. Indeed, the value of the estimated apparent cell stiffness integrates the effect of different geometrical parameters, the most important being the bead embedding angle 2γ, bead radius R, and cell height h. In this paper, a three-dimensional finite element analysis was used to compute the cell mechanical response to applied force in tweezer experiments and to explicit the correcting functions which have to be used in order to infer the intrinsic cell Young’s modulus from the apparent elasticity modulus. Our analysis, performed for an extensive set of values of γ, h, and R, shows that the most relevant parameters for computing the correcting functions are the embedding half angle γ and the ratio hu∕2R, where hu is the under bead cell thickness. This paper provides original analytical expressions of these correcting functions as well as the critical values of the cell thickness below which corrections of the apparent modulus are necessary to get an accurate value of cell Young’s modulus. Moreover, considering these results and taking benefit of previous results obtained on the estimation of cell Young’s modulus of adherent cells probed by magnetic twisting cytometry (MTC) (Ohayon, J., and Tracqui, P., 2005, Ann. Biomed. Eng., 33, pp. 131–141), we were able to clarify and to solve the still unexplained discrepancies reported between estimations of elasticity modulus performed on the same cell type and probed with MTC and optical tweezers (OT). More generally, this study may strengthen the applicability of optical and magnetic tweezers techniques by insuring a more precise estimation of the intrinsic cell Young’s modulus (CYM).

Mechanical properties of FeAlSi powders prepared by mechanical alloying from different initial feedstock materials

2019 ◽  
Vol 107 (2) ◽  
pp. 207 ◽  
Author(s):  
Jaroslav Čech ◽  
Petr Haušild ◽  
Miroslav Karlík ◽  
Veronika Kadlecová ◽  
Jiří Čapek ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Mechanical Alloying ◽  
Young’S Modulus ◽  
Milling Time ◽  
Young's Modulus ◽  
Element Model ◽  
X Ray Diffraction ◽  
X Ray ◽  
Powder Particles ◽  
Complete Homogenization

FeAl20Si20 (wt.%) powders prepared by mechanical alloying from different initial feedstock materials (Fe, Al, Si, FeAl27) were investigated in this study. Scanning electron microscopy, X-ray diffraction and nanoindentation techniques were used to analyze microstructure, phase composition and mechanical properties (hardness and Young’s modulus). Finite element model was developed to account for the decrease in measured values of mechanical properties of powder particles with increasing penetration depth caused by surrounding soft resin used for embedding powder particles. Progressive homogenization of the powders’ microstructure and an increase of hardness and Young’s modulus with milling time were observed and the time for complete homogenization was estimated.

Degradation of Rocks, Through Cracking Caused by Differential Thermal Expansion, in Relation to Nuclear Waste Repositories

1981 ◽  
Vol 6 ◽  
Author(s):  
J.R. Mclaren ◽  
R.W. Davidge ◽  
I. Titchell ◽  
K. Sincock ◽  
A. Bromley
Keyword(s):  
Thermal Expansion ◽  
Grain Boundary ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Crack Density ◽  
Granitic Rocks ◽  
Multiphase Materials ◽  
Thermal Expansion Behaviour ◽  
Waste Repositories ◽  
Expansion Behaviour

ABSTRACTHeating to temperatures up to 500°C, gives a reduction in Young's modulus and increase in permeability of granitic rocks and it is likely that a major reason is grain boundary cracking. The cracking of grain boundary facets in polycrystalline multiphase materials showing anisotropic thermal expansion behaviour is controlled by several microstructural factors in addition to the intrinsic thermal and elastic properties. Of specific interest are the relative orientations of the two grains meeting at the facet, and the size of the facet; these factors thus introduce two statistical aspects to the problem and these are introduced to give quantitative data on crack density versus temperature. The theory is compared with experimental measurements of Young's modulus and permeability for various rocks as a function of temperature. There is good qualitative agreement, and the additional (mainly microstructural) data required for a quantitative comparison are defined.

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