Combined effect of pores concavity and aspect ratio on the elastic properties of a porous material

2018 ◽  
Vol 134 ◽  
pp. 161-172 ◽  
Author(s):  
Fengjuan Chen ◽  
Igor Sevostianov ◽  
Albert Giraud ◽  
Dragan Grgic
Keyword(s):  
Aspect Ratio ◽  
Porous Material ◽  
Elastic Properties ◽  
Combined Effect

Micromechanics-based analyses of short fiber-reinforced composites with functionally graded interphases

2019 ◽  
Vol 54 (8) ◽  
pp. 1031-1048 ◽  
Author(s):  
Yang Yang ◽  
Qi He ◽  
Hong-Liang Dai ◽  
Jian Pang ◽  
Liang Yang ◽  
...  
Keyword(s):  
Aspect Ratio ◽  
Elastic Properties ◽  
Effective Properties ◽  
Micromechanical Model ◽  
Short Fiber ◽  
Functionally Graded ◽  
Fiber Reinforced Composites ◽  
Reinforced Composites ◽  
Fiber Reinforced ◽  
The Matrix

A micromechanical model for short fiber-reinforced composites (SFRCs) with functionally graded interphases and a systematic prediction scheme to determine the effective properties are presented. The matrix and the fibers are regarded to be linear elastic, isotropic, and homogeneous. Fibers are assumed to be ellipsoids coated perfectly by functionally graded interphases, which is supposed to be formed chemically or physically by the constituents near the interface. First, to analyze the grading interphase effect, layer-wise concept is followed to divide the functionally graded interphases into multi-homogeneous sub-layers. Next, to take the effect of functionally graded interphases into account, a combination of multi-inclusion method and Mori–Tanaka method is applied to predict effective elastic properties of this unidirectional SFRCs with respect to the content and aspect ratio of the inclusions. By employing coordinate transformation, spatially elastic moduli are obtained. Finally, Voigt homogenization scheme is used to obtain the overall, averaged, symmetrical elastic properties of the SFRCs. Numerical examples and analyses demonstrate the applicability of the proposed method and indicate the influences of graded interphase, orientation, and aspect ratio of inclusions as well as properties and contents of the constituents on the overall properties of SFRCs.

Combined Effect of Polishing on Surface Morphology and Elastic Properties of a Commercial Dental Restorative Resin Composite

2012 ◽  
Vol 4 (1) ◽  
pp. 126-134 ◽  
Author(s):  
Marco Salerno ◽  
Niranjan Patra ◽  
Sanjay Thorat ◽  
Giacomo Derchi ◽  
Alberto Diaspro
Keyword(s):  
Surface Morphology ◽  
Elastic Properties ◽  
Resin Composite ◽  
Combined Effect ◽  
Dental Restorative

Modeling squirt dispersion and attenuation in fluid-saturated rocks using pressure dependency of dry ultrasonic velocities

Geophysics ◽  
2012 ◽  
Vol 77 (3) ◽  
pp. WA157-WA168 ◽  
Author(s):  
Osni Bastos de Paula ◽  
Marina Pervukhina ◽  
Dina Makarynska ◽  
Boris Gurevich
Keyword(s):  
Aspect Ratio ◽  
Elastic Properties ◽  
Elastic Moduli ◽  
Pore Space ◽  
Geometrical Parameters ◽  
Laboratory Measurements ◽  
Significant Linear Trend ◽  
Aspect Ratios ◽  
Pressure Dependency ◽  
Dispersion And Attenuation

Modeling dispersion and attenuation of elastic waves in fluid-saturated rocks due to squirt flow requires the knowledge of a number of geometrical parameters of the pore space, in particular, the characteristic aspect ratio of the pores. These parameters are usually inferred by fitting measurements on saturated rocks to model predictions. To eliminate such fitting and thus make the model more predictive, we propose to recover the geometrical parameters of the pore space from the pressure dependency of elastic moduli on dry samples. Our analysis showed that the pressure dependency of elastic properties of rocks (and their deviation from Gassmann’s prediction) at ultrasonic frequencies is controlled by the squirt flow between equant, stiff, and so-called intermediate pores (with aspect ratios between [Formula: see text]). Such intermediate porosity is expected to close at confining pressures of between 200 and 2000 MPa, and thus cannot be directly obtained from ultrasonic experiments performed at pressures below 50 MPa. However, the presence of this intermediate porosity is inferred from the significant linear trend in the pressure dependency of elastic properties of the dry rock and the difference between the bulk modulus of the dry rock computed for spherical pores and the measured modulus at 50 MPa. Moreover, we can infer the magnitude of the intermediate porosity and its characteristic aspect ratio. Substituting these parameters into the squirt model, we have computed elastic moduli and velocities of the water-saturated rock and compared these predictions against laboratory measurements of these velocities. The agreement is good for a number of clean sandstones, but not unexpectedly worse for a broad range of shaley sandstones. Our predictions showed that dispersion and attenuation caused by the squirt flow between compliant and stiff pores may occur in the seismic frequency band. Confirmation of this prediction requires laboratory measurements of elastic properties at these frequencies.

scholarly journals Experimental Study of Pool Effect of Shear, Flexure and Torsion on SFRC Beams

2020 ◽  
Vol 9 (6) ◽  
pp. 233-236
Keyword(s):  
Experimental Study ◽  
Reinforced Concrete ◽  
Aspect Ratio ◽  
Steel Fiber ◽  
Concrete Beams ◽  
Fiber Reinforced Concrete ◽  
Combined Effect ◽  
Bending Stress ◽  
Steel Fiber Reinforced Concrete ◽  
Specific Fraction

Flexural, torsional, compressive and shear behavior of Steel Fiber Reinforced Concrete (SFRC) is already studied individually but none has studied the performance of SFRC beams under a combined effect of more than one state i.e. tension, flexure, torsion, compression and shear in general by now. In this study M20 grade of concrete beams under composite behavior of flexure, shear and torsion with different compositions of fibers mix were investigated. The dimensions of specimen beams was 100 mm x 100 mm x 500 mm and straight cylindrical fibers of length 0.28 mm and aspect ratio 100 were mixed. A total of 48 specimen were casted and tested such that for every percentage of fiber and each torsion value three beams were tested. Hence there are four torsion values 0, 61.75, 119.41 and 176.53 N-m are applied (4x3x4=48) It was found during study that ultimate bending stress and deflection increases due to increase in torsion where as the ductility reduced with the torsion enhancement for a specific fraction of fiber content.

scholarly journals A Novel Approach of Heat Rate Enhancement in Rectangular Channels with Thin Porous Layer at the Channel Walls

Sci ◽  
2021 ◽  
Vol 3 (4) ◽  
pp. 42
Author(s):  
Mohamad Ziad Saghir
Keyword(s):  
Reynolds Number ◽  
Aspect Ratio ◽  
Porous Material ◽  
Heat Rate ◽  
Reynolds Numbers ◽  
Heat Extraction ◽  
Metallic Foam ◽  
Novel Approach ◽  
Rectangular Channels ◽  
Porous Strip

Heat transfer enhancement is a topic of great interest nowadays due to its different applications in industries. A porous material also known as metallic foam plays a major role in heat enhancement at the expense of pressure drop. The flow in channels demonstrates the usefulness of this technology in heat extraction. In our current study, a porous strip attached to the walls of the channels is proposed as an alternative for heat enhancement. The thickness of the porous strip was varied for different Reynolds numbers. By maintaining a laminar regime and using water as a fluid, we determined an optimum thickness of porous material leading to the highest performance evaluation criterion. In our current study, with the aspect ratio being the porous strip thickness over the channel width, an aspect ratio of 0.2 is found to be the alternative. A 40% increase in heat enhancement is detected in the presence of a porous strip when compared to a clear channel case for a Reynolds number equal to 200, which improves further as the Reynolds number increases accordingly.

scholarly journals Novel Approach of Heat Rate Enhancement in a Rectangular Channels with Thin Porous Layer at the Channel Walls

2021 ◽  
Author(s):  
M. Z. Saghir
Keyword(s):  
Reynolds Number ◽  
Aspect Ratio ◽  
Porous Material ◽  
Heat Rate ◽  
Heat Extraction ◽  
Metallic Foam ◽  
Novel Approach ◽  
Rectangular Channels ◽  
Porous Strip ◽  
Drop Flow

Heat enhancement is a topic of great interest nowadays due to its different application in industries. Porous material also known as metallic foam plays a major role in heat enhancement at the expenses of pressure drop. Flow in channels demonstrate the usefulness of this technology in heat extraction. In our current study, a porous strip attached to the channels walls is proposed as an alternative for heat enhancement. The thickness of the porous strip was varied for different Reynolds number. By maintaining laminar regime and using water as fluid, we determined an optimum thickness of porous material leading to the highest performance evaluation criterion. In our current study with the aspect ratio being the porous strip thickness over the channel width, an aspect ratio of 0.2 is found to be the alternative. A 40% increase in heat enhancement is detected in the presence of porous strip when compared to a clear channel case for a Reynolds number equal to 200 and improve further as the Reynolds number increase accordingly.

Using laboratory data to understand how pore aspect ratio influences elastic parameters and AVO

Geophysics ◽  
2021 ◽  
pp. 1-50
Author(s):  
Kamal Moravej ◽  
Alison Malcolm
Keyword(s):  
Aspect Ratio ◽  
Elastic Properties ◽  
Wave Velocity ◽  
Selective Laser Sintering ◽  
Laboratory Data ◽  
Physical Models ◽  
P Wave ◽  
S Wave ◽  
Water Saturated ◽  
The Impact

Pore geometry is an important parameter in reservoir characterization that affects the permeability of reservoirs and can also be a controlling factor on the impact of pressure and saturation on reservoirs elastic properties. We use SLS (Selective Laser Sintering) 3D printing technology to build physical models to experimentally investigate the impacts of pore aspect ratio on P-, and S- wave velocities and amplitude variation with offset (AVO). We printed six models to study the effects of the pore aspect ratio of prolate and oblate pore structures on elastic properties and AVO signatures. We find that the P-wave velocity is reduced by decreasing the pore aspect ratio (flatter pore structure), whereas the shear wave velocity is less sensitive to the pore aspect ratio. This effect is reduced when the samples are water saturated. We present new experimental and processing techniques to extract realistic AVO signatures from our experimental data and show that the pore aspect ratio has similar effects on AVO as fluid compressibility. This shows that not considering the pore aspect ratio in AVO analysis can lead to misleading interpretations. We further show that these effects are reduced in water-saturated samples.

The Combined Effect of Axial Velocity Density Ratio and Aspect Ratio on Compressor Cascade Performance

1981 ◽  
Vol 103 (1) ◽  
pp. 247-255 ◽  
Author(s):  
U. Stark ◽  
H. Hoheisel
Keyword(s):  
Aspect Ratio ◽  
Velocity Distribution ◽  
Axial Velocity ◽  
Density Ratio ◽  
Combined Effect ◽  
Experimental Investigations ◽  
Compressor Cascade ◽  
Pressure Distributions ◽  
Contraction Ratio ◽  
Axial Velocity Distribution

The paper describes theoretical and experimental investigations on the combined effect of axial velocity density ratio (AVDR) and aspect ratio (AR) on compressor cascade performance in incompressible and compressible flow. The results presented demonstrate that it is the aspect ratio that defines the axial velocity distribution through the cascade at a given wall shape and contraction ratio. It is further shown that it is, in turn, the axial velocity distribution that decisively determines the local values of pressure distributions as well as the cascade overall parameters like turning angles and loss coefficients.

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