Simulation of Elastic Properties Using a Proposed Model for Gas Shales

2021 ◽  
Author(s):  
F.M. Lechuga Lagos ◽  
A. Aquino Lopez ◽  
S. Vega
Keyword(s):  
Elastic Properties ◽  
Proposed Model ◽  
Gas Shales

scholarly journals An Efficient Approach of Predicting the Elastic Property of Hydrating Cement Paste

2021 ◽  
Vol 8 ◽  
Author(s):  
Baoyu Ma ◽  
Guansuo Dui ◽  
Zhenglin Jia ◽  
Bo Yang ◽  
Chunyan Yang ◽  
...  
Keyword(s):  
Elastic Properties ◽  
Cement Paste ◽  
Volume Fraction ◽  
Solid Volume Fraction ◽  
Empirical Method ◽  
Elastic Behavior ◽  
Engineering Practice ◽  
Proposed Model ◽  
Hydration Model ◽  
Semi Empirical

Although elastic properties of hydrating cement paste are crucial in concrete engineering practice, there are only a few widely available models for engineers to predict the elastic behavior of hydrating cement paste. Therefore, in this paper, we derive an analytical model to efficiently predict the elastic properties (e.g., Young’s modulus) of hydrating cement paste. Notably, the proposed model provides the prediction of hydration, percolation, and homogenization of the cement paste, enabling the study of the early age elasticity evolution in cement paste. A hydration model considering the mineral composition and the initial w/c ratio was used, while the percolation threshold was calculated adopting a phenomenological semi-empirical method describing the effects of the solid volume fraction and the w/c ratio. An efficient mixing rule based on the degree of solid connectivity was then adopted to calculate the elastic properties of the hydrating cement paste. Moreover, for ordinary Portland cement, a simplified model was built using Powers’ hydration model. The obtained modeling results are following experimental data and other numerical results available in the literature.

Effective Transverse Elastic Properties of Composites Containing Two Types of Continuous Fibers

2007 ◽  
Vol 23 (4) ◽  
pp. 309-318
Author(s):  
P. J. Lin
Keyword(s):  
Elastic Properties ◽  
Current Approach ◽  
Two Phase ◽  
Reinforced Composite ◽  
Proposed Model ◽  
Three Phase ◽  
Local Solutions ◽  
Rigid Fibers ◽  
Interaction Problem ◽  
Properties Of Composites

AbstractBased the previously published model on the two-dimensional micromechanical fiber interaction framework of two-phase composites, effective transverse elastic properties of composites containing two types of randomly located yet unidirectionally aligned circular fibers are studied in this paper. Approximate local solutions for the interaction problem of two randomly located circular fibers of different elastic properties are presented. A fiber-reinforced composite material containing two extreme types of inclusions, voids and rigid fibers, is also investigated. Comparison with Hashin's variational bounds and Mori-Tanaka method, the current approach provides reasonably accurate predictions for three-phase composites. Finally, numerical simulation examples are implemented to demonstrate the capability of the proposed model.

Predicting subsurface CO2 movement: From laboratory to field scale

Geophysics ◽  
2012 ◽  
Vol 77 (3) ◽  
pp. M27-M37 ◽  
Author(s):  
Ranjana Ghosh ◽  
Mrinal K. Sen
Keyword(s):  
Elastic Properties ◽  
Carbonate Rocks ◽  
Water Saturation ◽  
Time Lapse ◽  
Carbonate Reservoir ◽  
S Wave ◽  
Permeability Enhancement ◽  
Proposed Model ◽  
Porosity And Permeability ◽  
Frequency Dependent Model

Finding an appropriate model for time-lapse seismic monitoring of [Formula: see text]-sequestered carbonate reservoir poses a great challenge because carbonate-rocks have varying textures and highly reactive rock-fluid system. We introduced a frequency-dependent model based on Eshelby’s inclusion and differential effective medium (DEM) theory that can account for heterogeneity in microstructure of rocks and squirt flow. We showed that the estimated velocities from the modified DEM theory match well with the laboratory measurements (ultrasonic) of velocities of carbonate rocks saturated with [Formula: see text]-rich water. The theory predicts significant decrease in saturated P- and S-wave velocities in the seismic frequency band as a consequence of porosity and permeability enhancement by the process of chemical dissolution of carbonates with the saturating fluid. The study also showed the combined effect of chemical reaction and free [Formula: see text] saturation on the elastic properties of rock. We observed that the velocity dispersion and attenuation increased from complete gas saturation to water saturation. The proposed model can be used to invert geophysical measurements to detect changes in elastic properties of a carbonate reservoir and interpret the extent of [Formula: see text] movement with time. These are the key elements to ensure that sequestration will not damage underground geologic formation and [Formula: see text] storage is secure and environmentally acceptable.

Elastic Properties of Zr50Cu43Ag7 Bulk Metallic Glass Using Pseudopotential Theory

2016 ◽  
Vol 1141 ◽  
pp. 232-235
Author(s):  
Chaudhari Prakruti ◽  
Payal N. Chauhan ◽  
R.H. Joshi ◽  
Nisarg K. Bhatt ◽  
Brijmohan Y. Thakore
Keyword(s):  
Metallic Glass ◽  
Bulk Metallic Glass ◽  
Elastic Properties ◽  
Young Modulus ◽  
Pseudopotential Theory ◽  
Transverse Modes ◽  
Local Field Correction ◽  
Proposed Model ◽  
Model Pseudopotential ◽  
Good Agreement

Using Hubbard-Beeby approach for phonon dynamics, in conjunction with our recently proposed model pseudopotential; phonon frequencies for longitudinal and transverse modes are computed and associated elastic properties of technologically important Zr-based Zr50Cu43Ag7 bulk metallic glass (BMG) are evaluated. Five different forms of the static local field correction functions, viz., Hartree etal. (H), Taylor et al. (T), Ichimaru and Utsumi et al. (IU), Farid et al. (F) and Sarkar et al. (S) are employed to investigate the influence of the screening effect on the vibrational dynamics of Zr50Cu43Ag7 BMG. Results for bulk modulus, modulus of rigidity, Poisson's ratio, Young modulus, propagation velocity of elastic waves and dispersion curves are studied. The theoretical computations are found to be in good agreement with the available experimental results, which confirms the use of our model pseudopotential to study elastic properties of such a glassy system.

Design of a New Testing Fixture for Tangential Stress Measurements in Pipes

2017 ◽  
Author(s):  
Abdennour Seibi ◽  
Majdi Chaari ◽  
Ahmed Temani ◽  
Mehdi Mokhtari ◽  
Charles Taylor
Keyword(s):  
Finite Element ◽  
Tensile Test ◽  
Contact Pressure ◽  
Elastic Properties ◽  
Ring Width ◽  
Orientation Angle ◽  
Gauge Length ◽  
Uniaxial Tensile ◽  
Width Ratio ◽  
Proposed Model

Experimental estimation of acurate material properties are key elements to the design of machine components and structures. In general, the elastic properties were determined using uniaxial tensile tests regardless of the final shape of the product including pipes, which exhibit different elastic properties in the longitudinal and tangential directions due to their manufacturing process. Several attempts have been made to estimate the mechanical properties of pipes along their longitudinal directions including ASTM D2290 and exhibited inconsistent results; thereby, calling for further design and analysis. This paper, therefore, presents various design alternatives to the ring hoop tensile test adopted in the ASTM D2290 standard through finite element modeling. The design optimization consisted of varying the ring width, dogbone width, dogbone gauge length, and the spacing between the two D-blocks to obtain the optimum values of the varying parameters that provide uniform normal stress across the cross-sectional area of the dogbone and more representative mechanical response. Finite element results revealed that the proposed dogbone sample design has an optimum length to width ratio of 4 with an orientation angle between 75° to 105° with respect to the horizontal axis. The proposed model was compared to adopted test methods such as ASTM D2290 and resulted in comparable stress contours uniformity across the dogbone gauge length but different contact pressure values. it was also found that the contact pressure for the ASTM ring hoop tensile test is higher than that for the proposed model by 22%.

A New Inverse Analysis Method for Identifying the Elastic Properties of Thin Films Considering Thickness and Substrate Effects Simultaneously

2017 ◽  
Vol 09 (07) ◽  
pp. 1750096 ◽  
Author(s):  
Nadia Chakroun ◽  
Aymen Tekaya ◽  
Hedi Belhadjsalah ◽  
Tarek Benameur
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Elastic Properties ◽  
Analysis Method ◽  
Innovative Methodology ◽  
Proposed Model ◽  
Indentation Tests ◽  
Reverse Analysis ◽  
Dimensional Analysis Method

This paper presents an innovative methodology for the measurement of the mechanical properties of thin films. The purpose is to identify the elastic properties of thin film materials considering the effects of thickness and substrate simultaneously. The new approach is based on the Dimensional Analysis Method (DAM) and the Finite Element Method (FEM) to develop the model’s explicit form. Using the reverse analysis method, numerical indentation tests were carried out to obtain the Young’s modulus of the film. Therefore, the identified film modulus was completely consistent with the input modulus, which ensures the reliability and the effectiveness of the proposed method. Moreover, a case study of TiN nanocoating deposited on Zr-Based Metallic Glasses was considered to validate the proposed model. This model is useful for thin film materials and can be used in different technological applications.

Impacts of nanopore structure and elastic properties on stress-dependent permeability of gas shales

2015 ◽  
Vol 26 ◽  
pp. 1663-1672 ◽  
Author(s):  
Rui Zhang ◽  
Zhengfu Ning ◽  
Feng Yang ◽  
Xin Wang ◽  
Huawei Zhao ◽  
...  
Keyword(s):  
Elastic Properties ◽  
Gas Shales ◽  
Nanopore Structure ◽  
Stress Dependent

Structure and Interaction of Protamine by Dark Field Electron Microscopy

1976 ◽  
Vol 34 ◽  
pp. 160-161
Author(s):  
D.P. Bazett-Jones ◽  
F.P. Ottensmeyer
Keyword(s):  
Electron Microscopy ◽  
Dark Field ◽  
Amino Acid Sequences ◽  
Dimensional Structure ◽  
3 Dimensional ◽  
Field Electron ◽  
Proposed Model ◽  
Field Electron Microscopy ◽  
Dark Field Electron ◽  
Positively Charged

It has been shown for some time that it is possible to obtain images of small unstained proteins, with a resolution of approximately 5Å using dark field electron microscopy (1,2). Applying this technique, we have observed a uniformity in size and shape of the 2-dimensional images of pure specimens of fish protamines (salmon, herring (clupeine, Y-l) and rainbow trout (Salmo irideus)). On the basis of these images, a model for the 3-dimensional structure of the fish protamines has been proposed (2).The known amino acid sequences of fish protamines show stretches of positively charged arginines, separated by regions of neutral amino acids (3). The proposed model for protamine structure (2) consists of an irregular, right-handed helix with the segments of adjacent arginines forming the loops of the coil.

Electron Microscopy and image reconstruction reveal the structural basis for spectrin's elastic properties

1992 ◽  
Vol 50 (1) ◽  
pp. 510-511
Author(s):  
Amy M. McGough ◽  
Robert Josephs
Keyword(s):  
Electron Microscopy ◽  
Elastic Properties ◽  
Conformational Changes ◽  
Quaternary Structure ◽  
Three Dimensional ◽  
Membrane Skeleton ◽  
Projection Algorithm ◽  
Structural Basis ◽  
Iterative Approximation ◽  
Membrane Skeletons

The remarkable deformability of the erythrocyte derives in large part from the elastic properties of spectrin, the major component of the membrane skeleton. It is generally accepted that spectrin's elasticity arises from marked conformational changes which include variations in its overall length (1). In this work the structure of spectrin in partially expanded membrane skeletons was studied by electron microscopy to determine the molecular basis for spectrin's elastic properties. Spectrin molecules were analysed with respect to three features: length, conformation, and quaternary structure. The results of these studies lead to a model of how spectrin mediates the elastic deformation of the erythrocyte.Membrane skeletons were isolated from erythrocyte membrane ghosts, negatively stained, and examined by transmission electron microscopy (2). Particle lengths and end-to-end distances were measured from enlarged prints using the computer program MACMEASURE. Spectrin conformation (straightness) was assessed by calculating the particles’ correlation length by iterative approximation (3). Digitised spectrin images were correlation averaged or Fourier filtered to improve their signal-to-noise ratios. Three-dimensional reconstructions were performed using a suite of programs which were based on the filtered back-projection algorithm and executed on a cluster of Microvax 3200 workstations (4).

The buckling of thin EM specimens

1990 ◽  
Vol 48 (4) ◽  
pp. 850-851
Author(s):  
A.R. Thölén
Keyword(s):  
Electron Microscope ◽  
Elastic Properties ◽  
Crystal Surface ◽  
Specimen Surface ◽  
Radius Of Curvature ◽  
Thin Foils ◽  
Thin Electron ◽  
Regular Patterns

Thin electron microscope specimens often contain irregular bend contours (Figs. 1-3). Very regular bend patterns have, however, been observed around holes in some ion-milled specimens. The purpose of this investigation is twofold. Firstly, to find the geometry of bent specimens and the elastic properties of extremely thin foils and secondly, to obtain more information about the background to the observed regular patterns.The specimen surface is described by z = f(x,y,p), where p is a parameter, eg. the radius of curvature of a sphere. The beam is entering along the z—direction, which coincides with the foil normal, FN, of the undisturbed crystal surface (z = 0). We have here used FN = [001]. Furthermore some low indexed reflections are chosen around the pole FN and in our fcc crystal the following g-vectors are selected:

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