Mechanical properties of lipid bilayers: a note on the Poisson ratio

Soft Matter ◽  
2019 ◽  
Vol 15 (44) ◽  
pp. 9085-9092 ◽  
Author(s):  
M. Mert Terzi ◽  
Markus Deserno ◽  
John F. Nagle
Keyword(s):  
Mechanical Properties ◽  
Lipid Bilayers ◽  
Poisson Ratio ◽  
Simulation Data

Experimental and simulation data are brought to bear on the Poisson ratio to answer the question, just how soft are biomembranes?

scholarly journals Evaluation Method of Granite Multiscale Mechanical Properties Based on Nanoindentation Technology

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Man Lei ◽  
Fa-ning Dang ◽  
Haibin Xue ◽  
Mingming He
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Uniaxial Compression ◽  
Compression Test ◽  
Evaluation Method ◽  
Poisson Ratio ◽  
Nanoindentation Test ◽  
Uniaxial Compression Test ◽  
Displacement Curve ◽  
Mineral Contents

In order to study the mechanical properties of granite at the micro- and nanoscale, the load-displacement curve, residual indentation information, and component information of the quartz, feldspar, and mica in granite were obtained using a nanoindentation test, a scanning electron microscope (SEM), and X-ray diffraction (XRD). The elastic modulus and the hardness of each component of the granite were obtained through statistical analysis. Treating rock as a composite material, the relation between the macro- and microscopic mechanical properties of rock was established through the theory of micromechanical homogenization. The transition from micromechanical parameters to macromechanical parameters was realized. The equivalent elastic modulus and Poisson’s ratio of the granite were obtained by the Self-consistent method, the Dilute method, and the Mori-Tanaka method. Compared with the elastic modulus and the Poisson ratio of granites measured by a uniaxial compression test and the available data, the applicability of the three methods were analyzed. The results show that the elastic modulus and hardness of the quartz in the granite is the largest, the feldspar is the second, the mica is the smallest. The main mineral contents in granite were analyzed using the semiquantitative method by XRD and the rock slice identification test. The elastic modulus and the Poisson ratio of granite calculated by three linear homogenization methods are consistent with those of the uniaxial compression test. After comparing the calculation results of the three methods, it is found that the Mori-Tanaka method is more suitable for studying the mechanical properties of rock materials. This method has an important theoretical significance and practical value for studying the quantitative relationship between macro- and micromechanical indexes of brittle materials. The research results provide a new method and an important reference for studying the macro-, micro-, and nanomechanical properties of rock.

Main-chain liquid-crystal elastomers versus side-chain liquid-crystal elastomers: similarities and differences in their mechanical properties

Soft Matter ◽  
2018 ◽  
Vol 14 (31) ◽  
pp. 6449-6462 ◽  
Author(s):  
D. Rogez ◽  
S. Krause ◽  
P. Martinoty
Keyword(s):  
Mechanical Properties ◽  
Liquid Crystal ◽  
Main Chain ◽  
Poisson Ratio ◽  
Side Chain ◽  
Similarities And Differences ◽  
Liquid Crystal Elastomers

The shear and Young moduli, the poly-domain to mono-domain transition, the Poisson ratio and the supercritical or subcritical nature of main-chain and side-chain liquid-crystal elastomers are characterized with various mechanical experiments.

Determination of Mechanical Properties of Thin Film on Silicon Wafer

2003 ◽  
Author(s):  
Enboa Wu ◽  
Albert J. D. Yang ◽  
Ching-An Shao ◽  
C. S. Yen
Keyword(s):  
Thin Film ◽  
Mechanical Properties ◽  
Thermal Expansion ◽  
Young’S Modulus ◽  
Silicon Wafer ◽  
Coefficient Of Thermal Expansion ◽  
Young's Modulus ◽  
Poisson Ratio ◽  
Bulk State

Nondestructive determination of Young’s modulus, coefficient of thermal expansion, Poisson ratio, and thickness of a thin film has long been a difficult but important issue as the film of micrometer order thick might behave differently from that in the bulk state. In this paper, we have successfully demonstrated the capability of determining all these four parameters at one time. This novel method includes use of the digital phase-shifting reflection moire´ (DPRM) technique to record the slope of wafer warpage under temperature drop condition. In the experiment, 1-um thick aluminum was sputtered on a 6-in silicon wafer. The convolution relationship between the measured data and the mechanical properties was constructed numerically using the conventional 3D finite element code. The genetic algorithm (GA) was adopted as the searching tool for search of the optimal mechanical properties of the film. It was found that the determined data for Young’s modulus (E), Coefficient of Thermal Expansion (CTE), Poisson ratio (ν), and thickness (h) of the 1.00 um thick aluminum film were 104.2Gpa, 38.0 ppm/°C, 0.38, and 0.98 um, respectively, whereas that in the bulk state were measured to be E=71.4 Gpa, CTE=23.0 ppm/°C, and ν=0.34. The significantly larger values on the Young’s modulus and the coefficient of thermal expansion determined by this method might be attributed to the smaller dislocation density due to the thin dimension and formation of the 5-nm layer of Al2O3 formed on top of the 1-um thick sputtered film. The Young’s Modulus and the Poisson ratio of this nano-scale Al2O3 film were then determined. Their values are consistent with the physical intuition of the microstructure.

In Plane Mechanical Properties of Tetrachiral and Antitetrachiral Hybrid Metastructures

2017 ◽  
Vol 84 (8) ◽  
Author(s):  
Huimin Li ◽  
Yongbin Ma ◽  
Weibin Wen ◽  
Wenwang Wu ◽  
Hongshuai Lei ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Strain Energy ◽  
Energy Analysis ◽  
Poisson Ratio ◽  
Theoretical Models ◽  
Uniaxial Tensile ◽  
Geometrical Parameters ◽  
Element Simulation ◽  
Ring Rotation ◽  
Anisotropic Mechanical Properties

A novel tetrachiral and antitetrachiral hybrid metastructure is proposed, and its in-plane mechanical properties are studied through strain energy analysis. Based on rigid ring rotation assumption, the analytical expression for the in-plane modulus of anisotropic tetrachiral and antitetrachiral hybrid metastructure is derived, and in-plane tensile experimental test and finite element simulation are performed and compared with the theoretical models. The corresponding in-plane anisotropic mechanical properties can be tuned with three independent dimensionless geometrical parameters, and effects of dimensionless geometrical parameters on the in-plane mechanical properties are studied systematically. Finally, an innovative tetrachiral and antitetrachiral hybrid metastructure stent is designed, and its mechanical behaviors under uniaxial tensile loading are investigated. It is found that the designed tetrachiral and antitetrachiral hybrid stent shows negative Poisson ratio properties, and the axial and circumferential deformation can be controlled through adjusting the spacing of unit cell along axial and circumferential directions.

Thrust Force Modeling of the Flagella-Like Swimming Micro-Robot

2013 ◽  
Vol 461 ◽  
pp. 930-941
Author(s):  
Ling Wang ◽  
Bai Chen ◽  
Peng Wang ◽  
Sun Chen ◽  
Qian Yun Zhu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Cross Section ◽  
Thrust Force ◽  
Rectangular Cross Section ◽  
Helix Angle ◽  
Simulation Data ◽  
Force Modeling ◽  
Macro Scale ◽  
Micro Robot ◽  
Resistive Force Theory

In this paper, helix tails with rectangular cross-section were designed for propelling a kind of flagella-like swimming robot. CFD (Computational Fluid Dynamics) software was applied to analyze the major influencing factors of the robots mechanical properties. It is revealed that the thrust reaches the maximum when the helix tails cross-section width is 0.36 times the diameter. Meanwhile, the helix tails should be designed according to the requirements with the largest diameter, close to but less than 45° helix angle and multi-turns under the limitation of the workspace. Combining these simulation data with the derivation process of Resistive Force Theory, the models for the mechanical properties simulation of the swimming robot were revised, and the explicit empirical formula of propulsive force is obtained. This model lays a good foundation for the robots motion control as well as unified mathematical description for macro-scale and micro-scale robots.

Mechanical Properties of Rocks Used for the Construction of Vehicular Bridges Supported by Pier Masonry

2012 ◽  
Vol 535-537 ◽  
pp. 1881-1888 ◽  
Author(s):  
Gustavo Mendoza-Chavez ◽  
Luis Horacio Martínez-Mártinez ◽  
David Joaquin Delgado-Hernandez ◽  
David De León Escobedo ◽  
Elia Mercedes Alonso Guzmán ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Risk Assessment ◽  
Mechanical Behavior ◽  
Poisson Ratio ◽  
Friction Angle ◽  
Masonry Structure ◽  
Stone Masonry ◽  
Wide Availability ◽  
Density Values ◽  
Ongoing Project

In Mexico, since the early stages of the civilization, the stone masonry has assumed an important role in construction due to the wide availability of this kind of material. Masonry is a material composed by bricks, carved or even rubble stones jointed without (dry joint) or with mortar (mortar joints); which is principally formed with sand, water and cementitiuos materials. The research presented in this paper deals with the procedure of obtaining the mechanical properties of rocks placed on piers of four vehicular bridges located in the south of the state of Mexico, these mechanical properties are compressive strength, modulus of elasticity, Poisson ratio, Cohesion and Internal friction Angle of the rocks as independent units, also are reported the Density values. All of these properties are necessary to conduct further research regarding the mechanical behavior of the pier as a structure since this piece of research is part of an ongoing project concerning risk assessment of vehicular bridges developed in Mexico. The identified rocks in masonry were volcanic igneous materials such as dacites, basalts, rhyolites, andesites and rusted andesites. The materials with the highest and the lowest mechanical properties are the basalt and the dacite respectively. It is recommended to use the dacite’s properties in order to perform a conservative analysis of the mechanical behavior of any masonry structure, located near the selected sample studied herein.

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