### Rigorous connection between physical properties of porous

son s ratio to have a positive value this coefficient is positive for most geological materials and we will as- sume in this paper that (a) As a remark we emphasize that (2) is assumed for the Poisson s ratio of the solid constituent/grain of the porous material. Although the effective Poisson s ratio

Get Price### Determination of Effective Elastic Properties of

theory is the poroelastic theory which assumes the significant portions of the pores and cracks are connected. for a microcracked solid as β= Nl. 2 (1) (no crack) material with Young s modulus E 0 and Poisson s ratio

Get Price### Micromechanical Analysis of Dynamic Behavior of

Both conventional and negative Poisson s ratio foams exhibit dispersion of acoustic waves as well as cut-off frequencies at which the group velocity tends to zero. This macroscopic behavior is attributed to micro-vibration of the foam cell ribs. The purpose of this article is to develop a micromechanical model of the cut-off frequency.

Get Price### The effect of microcracking upon the Poisson s ratio for

Microcracking-elasticity theories typically relate a decrement in elastic moduli to the number density N and the mean microcrack radius 〈a〉. In this paper four microcracking-modulus theories are rewritten in terms of the macroscopic observable parameters of Young s modulus and Poisson s ratio eliminating the specific dependence on the difficult to measure microscopic quantitiesN and

Get Price### P-SV wave propagation in heterogeneous media Velocity

P-wave velocity of 6 000 m/s the P-wave half-wavelength is 1 800 m and the S-wave half-wavelength is 1 000 m for a Poisson s ratio v = 0.25. Consequently a good choice for the grid spacing is around 100 m. t is chosen to give a causal signal which is approximately zero for negative time

Get Price### Effects of size and surface on the auxetic behaviour of

Oct 12 2016 · The coupling between deformations along the sample s loading and its lateral directions is governed by the Poisson s ratio which is defined as the negative ratio of the lateral normal strain to

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Poisson s ratio of porous and microcracked solids Theory and application to oxide superconductors journal November 1995 Dunn Martin L. Ledbetter Hassel Journal of Materials Research Vol. 10 Issue 11

Get Price### Polynomial relations for quasi-static mechanical

Employing the proposed quasi-static method Young s modulus Poisson s ratio and loss factor are measured for a poroelastic foam. The measured elastic properties are used in the Biot poroelasticity theory to predict the sound absorption coefficient of the foam. The prediction is finally compared with a standing wave tube measurement.

Get Price### Determination of Effective Elastic Properties of

cracked solid can be obtained by () ()()() 0 0 11 1 22 2 k k ij ij ijkl kl ij ijkl kl i ij j k ij PM M nbs V PP σσσσσ σ σ == = Δ ∑ (8) where P0 ()σij is the potential of a matrix material without cracks which has the following expression for an isotropic (no crack) material with Young s modulus E0 and Poisson s ratio

Get Price### Surface Ripples of Polymeric Nanofibers under Tension The

Poisson s ratios of the core and shell layers are assumed close to that of compressible and incompressible materials respectively.

Get Price### differential scheme for elastic properties of rocks with

A rigorous stable fixed-point is obtained for Poisson s ratio ν c of dry porous media where the location of this fixed-point depends only on the shape of the voids being added. Fixed-points occur at for spheres and ν c ≃πα/18 for cracks where α is the aspect ratio of penny-shaped cracks.

Get Price### Correlation between Poisson s ratio and porosity in porous

Feb 01 2006 · An innovative percolation model for the Poisson s ratio porosity dependence of isotropic and homogeneous porous solids was presented. This model proposed on the basis of the percolation models for

Get Price### Correlation between mechanical and conductive properties

of porous/microcracked metals Igor Sevostianov THEORETICAL AND APPLIED MECHANICS vol. 28-29 pp. Belgrade 2002 to pore aspect ratios and Poisson s ratio of the virgin material. For a solid with many pores (analyzed in the framework of the

Get Price### Blatz-Ko hyperelastic model for nonlinear finite element

Compared with the almost incompressibility of solid rubber the porosity of the foam material allows very large volume-reduced deformations and therefore has good energy absorption. At the small strain condition (less than 5 ) the material shows linear elasticity with Poisson s ratio of 0.3 or so.

Get Price### Correlation between Poisson s ratio and porosity in porous

Usually Poisson s ratio for porous materials is cal- u0001 u0002 fE culated according to Equation 1 from the Young s and pc − p E = E0 for p ≤ pc (2) shear modulus experimental data. Therefore the same pc approach was used for the experimental data investi- gated in our previous works 1 2 .

Get Price### Surface Ripples of Polymeric Nanofibers under Tension The

Poisson s ratios of the core and shell layers are assumed close to that of compressible and incompressible materials respectively.

Get Price### The effect of microcracking upon the Poisson s ratio for

Microcracking-elasticity theories typically relate a decrement in elastic moduli to the number density N and the mean microcrack radius 〈a〉. In this paper four microcracking-modulus theories are rewritten in terms of the macroscopic observable parameters of Young s modulus and Poisson s ratio eliminating the specific dependence on the difficult to measure microscopic quantitiesN and

Get Price### Rigorous connection between physical properties of porous

son s ratio to have a positive value this coefficient is positive for most geological materials and we will as- sume in this paper that (a) As a remark we emphasize that (2) is assumed for the Poisson s ratio of the solid constituent/grain of the porous material. Although the effective Poisson s ratio

Get Price### Factors determining Poisson s ratio Semantic Scholar

ABSTRACT Poisson s ratio is determined by two independent factors i.e. the solid rock and dry or wet cracks. The former is influenced by the constituent mineral composition. The higher Poisson s ratio of the rock solid is the higher is Poisson s ratio of the rock.

Get Price### Porosity-dependence of Effective Mechanical Properties of

New models for the elastic properties (Young s and shear moduli bulk modulus and Poisson s ratio) of two-phase pore-solid composites are developed using the differential effective medium approach Porosity-dependence of Effective Mechanical Properties of Pore-solid Composite Materials

Get Price### Deformation mechanisms Negative Poisson s ratio materials

Poisson s ratio in materials is governed by the following aspects of the microstructure the presence of rotational degrees of freedom non-affine deformation kinematics or anisotropic structure. Several structural models are examined.

Get Price### differential scheme for elastic properties of rocks with

A rigorous stable fixed-point is obtained for Poisson s ratio ν c of dry porous media where the location of this fixed-point depends only on the shape of the voids being added. Fixed-points occur at for spheres and ν c ≃πα/18 for cracks where α is the aspect ratio of penny-shaped cracks.

Get Price### (PDF) NEGATİF POİSSON ORANINA SAHİP (AUXETIC)

Ledbetter H. and Lei M. (1991) Poisson s Ratio of Porous and Microcracked Solids Bandaj ile Sarılmış yara İltihaplanmış Yara Şişer Yara İyileşir Theory and Application to Oxide Superconductors Journal of Materials Research 6 2253–2255.

Get Price### Dynamic Pressurization Method for Measuring

Poisson s ratio of the solid is known or can be estimated. The analysis of the DP experiment is based on the theory developed by Biot 21 and discussed in detail by Coussy 22 . The application of the theory to problems of the are Young s modulus and Poisson s ratio for the drained porous solid.

Get Price### Cracked media Poisson s ratio and the structure of the

unchanged. This dependence of Poisson s ratio on crack aspect ratio was previously noted by Hyndman (1979). Figure 3 illustrates the increase in Poisson s ratio for a thin-cracked material (d = 0.001) as a function of porosity while Fig. 4 shows the decrease in Poisson s ratio for a thick-cracked material (d = 0.1). Note the difference in

Get Price### Rigorous connection between physical properties of porous

son s ratio to have a positive value this coefficient is positive for most geological materials and we will as- sume in this paper that (a) As a remark we emphasize that (2) is assumed for the Poisson s ratio of the solid constituent/grain of the porous material. Although the effective Poisson s ratio

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