scholarly journals Influence of Poisson’s Ratio on the Stress vs. Settlement Behavior of Shallow Foundations in Unsaturated Fine-Grained Soils

2016 ◽  
pp. 71-79
Author(s):  
Won Taek Oh ◽  
Sai K. Vanapalli
Keyword(s):  
Poisson’S Ratio ◽  
Unsaturated Soils ◽  
Shallow Foundations ◽  
Poisson's Ratio ◽  
Degree Of Saturation ◽  
Elastic Continuum ◽  
Fine Grained ◽  
Linear Elastic ◽  
Settlement Behavior ◽  
The Relationship

Poisson’s ratio is typically assumed to be constant for both saturated and unsaturated soils. However, the back-calculated Poisson’s ratio using the relationship between elastic and shear modulus (i.e. the equation for homogeneous, isotropic and linear elastic continuum) published in the literature showed that the Poisson’s ratio is not constant but decreases with the degree of saturation (or increasing suction). In the present study, more focused investigations are undertaken to study the influence of Poisson’s ratio on the stress vs. settlement (SVS) behaviour of shallow foundations in an unsaturated fine-grained (UFG) soil. The FEA are carried out using the software, SIGMA/W (GeoStudio 2007) to better understand the SVS behavior taking account of the influence of Poisson’s ratio for different matric suction values and compared with the model footing tests conducted in an UFG soil. Several suggestions are made with respect to the influence of Poisson’s ratio on the SVS behavior of shallow foundations in the UFG soils based on the results of this study.

The Model for Calculating Elastic Modulus and Poisson's Ratio of Coal Body

2013 ◽  
Vol 6 (1) ◽  
pp. 36-43 ◽  
Author(s):  
Ai Chi ◽  
Li Yuwei
Keyword(s):  
Elastic Modulus ◽  
Poisson’S Ratio ◽  
Fractured Rock ◽  
Rock Block ◽  
Poisson's Ratio ◽  
Linear Elastic ◽  
Study Results ◽  
The Face ◽  
Block Face ◽  
Coal Rock

Coal body is a type of fractured rock mass in which lots of cleat fractures developed. Its mechanical properties vary with the parametric variation of coal rock block, face cleat and butt cleat. Based on the linear elastic theory and displacement equivalent principle and simplifying the face cleat and butt cleat as multi-bank penetrating and intermittent cracks, the model was established to calculate the elastic modulus and Poisson's ratio of coal body combined with cleat. By analyzing the model, it also obtained the influence of the parameter variation of coal rock block, face cleat and butt cleat on the elastic modulus and Poisson's ratio of the coal body. Study results showed that the connectivity rate of butt cleat and the distance between face cleats had a weak influence on elastic modulus of coal body. When the inclination of face cleat was 90°, the elastic modulus of coal body reached the maximal value and it equaled to the elastic modulus of coal rock block. When the inclination of face cleat was 0°, the elastic modulus of coal body was exclusively dependent on the elastic modulus of coal rock block, the normal stiffness of face cleat and the distance between them. When the distance between butt cleats or the connectivity rate of butt cleat was fixed, the Poisson's ratio of the coal body initially increased and then decreased with increasing of the face cleat inclination.

scholarly journals Modelling the elastic mechanical properties of bioactive glass-derived scaffolds

2020 ◽  
Vol 6 (1) ◽  
pp. 50-56
Author(s):  
Francesco Baino ◽  
Elisa Fiume
Keyword(s):  
Elastic Properties ◽  
Poisson’S Ratio ◽  
Mechanical Performance ◽  
Solid Material ◽  
Poisson's Ratio ◽  
Predictive Capability ◽  
Shear Moduli ◽  
Wide Range ◽  
Constitutive Parameters ◽  
The Relationship

AbstractPorosity is known to play a pivotal role in dictating the functional properties of biomedical scaffolds, with special reference to mechanical performance. While compressive strength is relatively easy to be experimentally assessed even for brittle ceramic and glass foams, elastic properties are much more difficult to be reliably estimated. Therefore, describing and, hence, predicting the relationship between porosity and elastic properties based only on the constitutive parameters of the solid material is still a challenge. In this work, we quantitatively compare the predictive capability of a set of different models in describing, over a wide range of porosity, the elastic modulus (7 models), shear modulus (3 models) and Poisson’s ratio (7 models) of bioactive silicate glass-derived scaffolds produced by foam replication. For these types of biomedical materials, the porosity dependence of elastic and shear moduli follows a second-order power-law approximation, whereas the relationship between porosity and Poisson’s ratio is well fitted by a linear equation.

scholarly journals Estimation of the Poisson’s Rate of the Intact Rock in the Function of the Rigidity

2019 ◽  
Author(s):  
Benedek A. Lógó ◽  
Balázs Vásárhelyi
Keyword(s):  
Poisson’S Ratio ◽  
Experimental Error ◽  
Limit Equilibrium ◽  
Material Constant ◽  
Friction Angle ◽  
Intact Rock ◽  
Poisson's Ratio ◽  
Mechanical Parameters ◽  
Linear Elastic ◽  
Rock Types

Although Poisson’s ratio is one of the basic rock mechanical parameters, it is less investigated than the other parameters. It can be assumed, that this material constant depends on the rigidity of the rock, among the others. The goal of this research is to find a theoretical relationship between the rigidity of the intact rock and Poisson’s ratio. It was assumed that there is a connection between the internal friction angle (or cohesion) and rigidity of the isotropic, linear elastic material, using the Mohr-Coulomb theory. Based on these equations from different published limit equilibrium, six different equations were compared. It is published that the rigidity value is equal (within the experimental error) to the Hoek-Brown material constant (mi) which value is well-known for many different rock types. Plotting the published Poisson’s ratio in the function of the rigidity of the intact rock the optimal connection was chosen.

Poisson’s Ratio Characteristic Curve of Unsaturated Soils

2021 ◽  
Vol 147 (1) ◽  
pp. 04020149
Author(s):  
Sannith Kumar Thota ◽  
Toan Duc Cao ◽  
Farshid Vahedifard
Keyword(s):  
Poisson’S Ratio ◽  
Unsaturated Soils ◽  
Characteristic Curve ◽  
Poisson's Ratio

Study on a New Testing Method of the Elastic Modulus and Poisson's Ratio by Using Brazilian Disk Test

2013 ◽  
Vol 347-350 ◽  
pp. 1199-1202
Author(s):  
Fei Wu ◽  
Shi Ming Dong
Keyword(s):  
Elastic Modulus ◽  
Poisson’S Ratio ◽  
Vertical Direction ◽  
Test Method ◽  
Poisson's Ratio ◽  
Theoretical Formula ◽  
Brazilian Disk ◽  
Total Displacement ◽  
The Relationship ◽  
Poissons Ratio

In order to develop a new test method of the elastic modulus and Poissons ratio, based on the theoretical analysis of the Brazilian disk diametrically loaded by a pair of forces, the relationship is obtained between the total displacement of one point on the vertical direction of the load line and the applied force as well as the elastic modulus and Poissons ratio. The strain gauges with different length are used to measure the displacement of the corresponding point, and then the displacement is employed to calculate the elastic modulus and Poisson's ratio by using the theoretical formula. The proposed method can provide a new approach to estimate the elastic modulus and Poissons ratio by using Brazilian disk splitting tests.

The Effect of Fiber Microstructure on the Observed Poisson’s Ratio of Tendon and Ligament Tissue

2008 ◽  
Author(s):  
Shawn P. Reese ◽  
Steve A. Maas ◽  
Heath A. Henninger ◽  
Jeffrey A. Weiss
Keyword(s):  
Poisson’S Ratio ◽  
Collagen Fiber ◽  
Poisson's Ratio ◽  
Fiber Direction ◽  
Exact Nature ◽  
Tendon Tissue ◽  
Element Analysis ◽  
The Relationship ◽  
Poisson's Ratios ◽  
Poisson’S Ratios

During tensile testing along the predominant collagen fiber direction, ligament and tendon tissue exhibit large Poisson’s ratios ranging from 1.3 in capsular ligament to 2.98 in flexor tendon [1][2]. Although the microstructure of these tissues (especially fiber crimp) has been characterized, the relationship between microstructure and Poisson’s ratio is relatively unexplored. There has been debate regarding the exact nature of the characteristic crimp within tendon fibers, however the two views most present in the literature are that of planar crimp and helical crimp. The aim of this study was to perform a finite element analysis on prototypical models of fibril bundles for both forms of crimp under tensile loading conditions. It was hypothesized that planar crimp alone would be insufficient for generating large Poisson’s ratios, and that some other microstructure (such as a helix) would be required.

scholarly journals First-Principle Studies on the Mechanical and Electronic Properties of AlxNiyZrz (x = 1~3, y = 1~2, z = 1~6) Alloy under Pressure

Materials ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 4972
Author(s):  
Xiaoli Yuan ◽  
Weikang Li ◽  
Peng Wan ◽  
Mi-An Xue
Keyword(s):  
Electronic Properties ◽  
Young’S Modulus ◽  
Poisson’S Ratio ◽  
Young's Modulus ◽  
Central Force ◽  
Poisson's Ratio ◽  
Electron Effective Mass ◽  
Superconducting Material ◽  
Pressure Scale ◽  
The Relationship

The elastic and electronic properties of AlxNiyZrz (AlNiZr, Al2NiZr6, AlNi2Zr, and Al5Ni2Zr) under pressure from 0 to 50 GPa have been investigated by using the density function theory (DFT) within the generalized gradient approximation (GGA). The elastic constants Cij (GPa), Shear modulus G (GPa), Bulk modulus B (GPa), Poisson’s ratio σ, Young’s modulus E (GPa), and the ratio of G/B have been studied under a pressure scale to 50 GPa. The relationship between Young’s modulus of AlxNiyZrz is Al5Ni2Zr > AlNiZr > Al2NiZr6 > AlNi2Zr, which indicates that the relationship between the stiffness of AlxNiyZrz is Al5Ni2Zr > AlNiZr > Al2NiZr6 > AlNi2Zr. The conditions are met at 30 and 50 GPa, respectively. What is more, the G/B ratios for AlNiZr, AlNi2Zr, Al2NiZr6, and Al5Ni2Zr classify these materials as brittle under zero pressure, while with the increasing of the pressure the G/B ratios of AlNiZr, AlNi2Zr, Al2NiZr6, and Al5Ni2Zr all become lower, which indicates that the pressure could enhance the brittle properties of these materials. Poisson’s ratio studies show that AlNiZr, AlNi2Zr, and Al2NiZr6 are all a central force, while Al5Ni2Zr is a non-central force pressure scale to 50 GPa. The energy band structure indicates that they are all metal. The relationship between the electrical conductivity of AlxNiyZrz is Al2NiZr6 > Al5Ni2Zr > AlNi2Zr > AlNiZr. What is more, compared with Al5Ni2Zr, AlNi2Zr has a smaller electron effective mass and larger atom delocalization. By exploring the elastic and electronic properties, they are all used as a superconducting material. However, Al5Ni2Zr is the best of them when used as a superconducting material.

Modified SFG Model for Unsaturated Soils

2011 ◽  
Vol 243-249 ◽  
pp. 2627-2633
Author(s):  
Min Liu ◽  
Cheng Gang Zhao ◽  
Yan Liu
Keyword(s):  
Unsaturated Soils ◽  
Void Ratio ◽  
Degree Of Saturation ◽  
Modified Model ◽  
Model Based ◽  
Different Types ◽  
Volumetric Model ◽  
Yield Surfaces ◽  
The Relationship

SFG model has some advantages that it is more flexible in modeling different types of unsaturated soils than most other models in the literature. However, there are some shortages in SFG model. Firstly, it did not take account the influence of degree of saturation on the deformation of soil. Additionally, the SWCC that was adopted in the SFG model is relatively simple and cannot reflect the relationship between the current void ratio and the degree of saturation. This paper firstly presents the modified model based on the SFG model. The modified model adds the degree of saturation into the volumetric model for unsaturated soils. In addition, it adopts a SWCC that can reflect the influence of current void ratio. The new yield surfaces are proposed. These new yield surfaces are not only the function of suction and mean net stress, but also the function of the current degree of saturation and void ratio of soil. The modified SFG model can model more types of the behaviors of unsaturated soils and is more reasonable than SFG model.

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