Modeling the viscoplastic behaviour of clays during consolidation: application to Berthierville clay in both laboratory and field conditions

2001 ◽  
Vol 38 (3) ◽  
pp. 484-497 ◽  
Author(s):  
Yun Tae Kim ◽  
S Leroueil
Keyword(s):  
Strain Rate ◽  
Effective Stress ◽  
Soft Clay ◽  
Field Conditions ◽  
Combined Processes ◽  
Natural Clay ◽  
Viscoplastic Strain ◽  
Proposed Model ◽  
The Difference ◽  
Predicted Values

To analyze the effects of strain rate and viscoplastic strain on consolidation of natural clay, this paper presents a nonlinear viscoplastic model in which viscoplastic behaviour is modeled by a unique effective stress (σ'v) – viscous strain (εv) – viscous strain rate (ε·v) relationship. The proposed model can consider the effects of strain rate and viscoplastic strain on consolidation, to take into account the difference in strain rate between laboratory and field conditions, and the combined processes of generation and dissipation of pore pressure during consolidation. This model can also predict the behaviour of clay during stepwise loading, constant rate of strain, and relaxation of effective stress. The predicted values using numerical analysis are compared with measured values in laboratory tests and in situ, under an embankment built on soft clay at Berthierville, Quebec. It is possible to estimate the consolidation behaviour of natural clay with reasonable accuracy using the proposed nonlinear viscoplastic model.Key words: consolidation, soft clay, strain rate, viscoplastic, relaxation.

A Simple Effective Stress Approach for Modeling Rate-Dependent Strength of Soft Clay

2018 ◽  
Vol 140 (4) ◽  
Author(s):  
Jiang Tao Yi ◽  
Yu Ping Li ◽  
Shan Bai ◽  
Yong Fu ◽  
Fook Hou Lee ◽  
...  
Keyword(s):  
Strain Rate ◽  
Effective Stress ◽  
Large Strain ◽  
Soft Clay ◽  
Yield Locus ◽  
Submarine Landslides ◽  
Fine Grained ◽  
Rate Dependent ◽  
Modified Cam Clay ◽  
Free Falling

This paper proposes a simple effective stress method for modeling the strain rate-dependent strength behavior that is experienced by many fine-grained soils in offshore events when subjected to rapid, large strain, undrained shearing. The approach is based on correlating the size of the modified Cam-Clay yield locus with strain rate, i.e., yield locus enlarging or diminishing dependent on the strain rate. A viscometer-based method for evaluating the needed parameters for this approach is provided. The viscometer measurements showed that strain rate parameters are largely independent of water content and agree closely with data from a previous study. Numerical analysis of the annular simple shear situation induced by the viscometer shows remarkable agreement with the experimental data provided the remolding-induced strength degradation effect is accounted for. The proposed method allows offshore foundation installation processes such as dynamically installed offshore anchors, free-falling penetrometer, and submarine landslides to be more realistically analyzed through effective stress calculations.

Modelling the combined effect of strain rate and temperature on one-dimensional compression of soils

2008 ◽  
Vol 45 (12) ◽  
pp. 1765-1777 ◽  
Author(s):  
L. Laloui ◽  
S. Leroueil ◽  
S. Chalindar
Keyword(s):  
Strain Rate ◽  
Yield Stress ◽  
Effective Stress ◽  
Void Ratio ◽  
Coupled Model ◽  
One Dimensional ◽  
The Third ◽  
Proposed Model ◽  
Effects Of Temperature ◽  
Advanced Model

Strain rate and temperature have important effects on the behaviour of soils. The present paper enhances the thermoviscoplastic modelling of soils by taking advantage of the most recent understanding of the effects of temperature and strain rate on soils. In particular, modelling of the evolution of the vertical yield stress at any void ratio is made possible with the use of an advanced model for the dependence of vertical yield stress on temperature, as well as the use of the unique effective stress–strain – strain rate concept. The first part of the paper presents an overview of the experimental and constitutive theoretical works performed on the effects of strain rate and temperature. The second part describes a strain rate and temperature coupled model, and the third part deals with the numerical validation of the proposed model.

Thermoelectric Power of the Liquid Sn—Te Alloy

1982 ◽  
Vol 37 (10) ◽  
pp. 1127-1131 ◽  
Author(s):  
D. H. Kurlat ◽  
M. Rosen
Keyword(s):  
Thermoelectric Power ◽  
Hard Sphere ◽  
Stoichiometric Composition ◽  
Band Model ◽  
Liquid Alloys ◽  
Sphere Approximation ◽  
The Difference ◽  
Predicted Values ◽  
Experimental Values ◽  
Two Band Model

The Seebeck coefficient (S) of Sni1-x- Tex liquid alloys was measured as a function of concentration and temperature. For 0 ≦ x <0.45 the behaviour is metallic; S values are small and negative, rising linearly with temperature. The predicted values of Ziman's theory when using the hard sphere approximation disagree with the experimental ones. The change in sign occurs for 0.45. For x = 0.5 (stoichiometric composition) the thermoelectric power decreases linearly with temperature. This fact is explained assuming a two-band model. For x ≧ 0.6 the liquid alloy becomes more semiconducting and presents a maximum in the isotherms of S for x = 0.65. For the excess tellurium concentration range we have calculated the difference EF - EV and γ/kB, assuming a S(1/T) law. The experimental values are compared with those of Dancy and Glazov.

Modeling and simulation of saturated double rotor induction machine

2018 ◽  
Vol 37 (3) ◽  
pp. 1139-1165
Author(s):  
Koosha Choobdari Omran ◽  
Ali Mosallanejad
Keyword(s):  
Temperature Effects ◽  
Power Efficiency ◽  
Reactive Power ◽  
Induction Machine ◽  
Transient Behavior ◽  
State Equations ◽  
Content Type ◽  
Proposed Model ◽  
The Difference ◽  
Park Transformation

Purpose Double rotor induction machine (DRIM) is a particular type of induction machine (IM) that has been introduced to improve the parameters of the conventional IM. The purpose of this study is to propose a dynamic model of the DRIM under saturated and unsaturated conditions by using the equations obtained in this paper. Also, skin and temperature effects are considered in this model. Design/methodology/approach First, the DRIM structure and its performance will be briefly reviewed. Then, to realize the DRIM model, the mathematical equations of the electrical and mechanical part of the DRIM will be presented by state equations in the q-d axis by using the Park transformation. In this paper, the magnetizing fluxes saturation is included in the DRIM model by considering the difference between the amplitudes of the unsaturated and saturated magnetizing fluxes. The skin and temperature effects are also considered in this model by correcting the rotor and stator resistances values during operation. Findings To evaluate the effects of the saturation and skin effects on DRIM performance and validate the model, the machine is simulated with/without consideration of saturation and skin effects by the proposed model. Then, the results, including torque, speed, stator and rotor currents, active and reactive power, efficiency, power factor and torque-speed characteristic, are compared. In addition, the performance of the DRIM has been investigated at different speed conditions and load variations. The proposed model is developed in Matlab/Simulink for the sake of validation. Originality/value This paper presents an understandable model of DRIM with and without saturation, which can be used to analyze the steady-state and transient behavior of the motor in different situations.

scholarly journals Investigating the Temporal Effect of User Preferences with Application in Movie Recommendation

2017 ◽  
Vol 2017 ◽  
pp. 1-10 ◽  
Author(s):  
Wen-Jun Li ◽  
Qiang Dong ◽  
Yan Fu
Keyword(s):  
Rapid Development ◽  
User Preferences ◽  
Mobile Internet ◽  
Smart Devices ◽  
Data Sets ◽  
Rating Data ◽  
Temporal Effect ◽  
Proposed Model ◽  
Target User ◽  
The Difference

As the rapid development of mobile Internet and smart devices, more and more online content providers begin to collect the preferences of their customers through various apps on mobile devices. These preferences could be largely reflected by the ratings on the online items with explicit scores. Both of positive and negative ratings are helpful for recommender systems to provide relevant items to a target user. Based on the empirical analysis of three real-world movie-rating data sets, we observe that users’ rating criterions change over time, and past positive and negative ratings have different influences on users’ future preferences. Given this, we propose a recommendation model on a session-based temporal graph, considering the difference of long- and short-term preferences, and the different temporal effect of positive and negative ratings. The extensive experiment results validate the significant accuracy improvement of our proposed model compared with the state-of-the-art methods.

A Simple Constitutive Model for Prediction of Single-Peak Flow Curves Under Hot Working Conditions

2016 ◽  
Vol 138 (2) ◽  
Author(s):  
Roxana Baktash ◽  
Hamed Mirzadeh
Keyword(s):  
Flow Stress ◽  
Strain Rate ◽  
Peak Flow ◽  
Rate Sensitivity ◽  
Peak Strain ◽  
Flow Curves ◽  
Hollomon Parameter ◽  
Proposed Model ◽  
Stress Coefficient ◽  
Hollomon Equation

The hot flow stress of a typical stainless steel was modeled by the Hollomon equation, a modified form of the Hollomon equation, and another modified form based on the Fields–Backofen equation. The coupled effect of the deformation temperature and strain rate was also taken into account in the proposed formulae by consideration of the Zener–Hollomon parameter or dependency of the constants on temperature. The modified Fields–Backofen equation was found to be appropriate for prediction of flow stress, in which the incorporation of peak strain and consideration of temperature dependencies of the strain rate sensitivity and the stress coefficient were found to be beneficial. Moreover, the simplicity of the proposed model justifies its applicability for expressing hot flow stress characterizing dynamic recrystallization (DRX).

Dynamic Hardness of MCrAlY Abradable Seal Coating

2021 ◽  
Vol 1035 ◽  
pp. 591-595
Author(s):  
Dan Guo ◽  
Jian Ming Liu ◽  
De Ming Zhang ◽  
Xin Zhang ◽  
Tong Liu
Keyword(s):  
Strain Rate ◽  
Split Hopkinson Pressure Bar ◽  
Hopkinson Pressure Bar ◽  
Dynamic Hardness ◽  
Mcraly Coating ◽  
Static Hardness ◽  
Split Hopkinson ◽  
The Difference ◽  
Pressure Bar ◽  
Abradable Coatings

The purpose of this investigation is to study the dynamic hardness of MCrAlY abradable coatings under different strain rates. A dynamic indentation device based on the split Hopkinson pressure bar system (SHPB) was used. The results show that the hardness of MCrAlY coating increased with the increase of the strain rate, which has a positive strain rate effect. In addition, the difference of the static hardness of MCrAlY coating prepared by HVOF and LPPS was only 4%, while the difference in dynamic hardness was 16%.

Diagnosis of infertility from adenomyosis and endometriosis through entroxon based intelligent water drop back propagation neural networks

2022 ◽  
pp. 1-9
Author(s):  
P. Vijayalakshmi ◽  
K. Muthumanickam ◽  
G. Karthik ◽  
S. Sakthivel
Keyword(s):  
Clustering Algorithm ◽  
Water Drop ◽  
Back Propagation ◽  
Back Propagation Neural Network ◽  
Uterine Wall ◽  
Health Issues ◽  
Testing Dataset ◽  
Proposed Model ◽  
Fuzzy C Means Clustering ◽  
The Difference

Adenomyosis is an abnormality in the uterine wall of women that adversely affects their normal life style. If not treated properly, it may lead to severe health issues. The symptoms of adenomyosis are identified from MRI images. It is a gynaecological disease that may lead to infertility. The presence of red dots in the uterus is the major symptom of adenomyosis. The difference in the extent of these red dots extracted from MRI images shows how significant the deviation from normality is. Thus, we proposed an entroxon-based bio-inspired intelligent water drop back-propagation neural network (BIWDNN) model to discover the probability of infertility being caused by adenomyosis and endometriosis. First, vital features from the images are extracted and segmented, and then they are classified using the fuzzy C-means clustering algorithm. The extracted features are then attributed and compared with a normal person’s extracted attributes. The proposed BIWDNN model is evaluated using training and testing datasets and the predictions are estimated using the testing dataset. The proposed model produces an improved diagnostic precision rate on infertility.

Assessment of the Efficiency of Aliquat 336+Rice Bran Oil for Separation of Acrylic Acid from Aqueous Solution Using Reactive Extraction

2018 ◽  
Vol 16 (9) ◽  
Author(s):  
Himangshu Mondal ◽  
Kanti Kumar Athankar ◽  
Kailas L. Wasewar
Keyword(s):  
Acrylic Acid ◽  
Rice Bran ◽  
Renewable Resources ◽  
Extraction Efficiency ◽  
Process Development ◽  
Rice Bran Oil ◽  
Reactive Extraction ◽  
Aliquat 336 ◽  
Proposed Model ◽  
Predicted Values

Abstract Biomass is an attractive target in process development for the emerging renewable resources based bio-refinery industry. Due to the ample range of application of acrylic acid, its production through bio-route received more awareness in scientific fraternity. In this view, an attempted was made to study the reactive extraction of acrylic acid with aliquat 336 in rice bran oil. Moreover, Box-Behnken matrix was employed to corroborate the effects of process variables viz. concentration of acrylic acid [CAA]aq, concentration of aliquat 336 [CR4N+Cl], and temperature on the extraction efficiency (η%). In physical extraction, average extraction efficiency was found in the order as: 43.55 > 35.36 > 29.14 at 303 K, 323 K, and 343 K respectively in rice bran oil. The correlation coefficient, R2 = 0.988 % indicates the appropriateness of proposed model to predict the extraction efficiency in terms of independent variables, and the predicted values were found in close agreement with that of experimental results. Further, R2(Pred) = 0.806 is in reasonable agreement with the R2(Adj) = 0.972. The optimum conditions for extraction of acrylic acid using aliquat 336 as an extractant in rice bran oil are [CAA]aq = 0.0.5 (mol/kg); [CR4N+Cl] = 1.98 (mol/kg); temperature = 323 K and the model predicted extraction efficiency 77.5 % was found to be an excellent fit with the experimental value 75 %. Further, number of theoretical stages was found to be 3 and S/F ratio 0.247.

scholarly journals A Novel Active Contours Model for Environmental Change Detection from Multitemporal Synthetic Aperture Radar Images

2020 ◽  
Vol 12 (11) ◽  
pp. 1746
Author(s):  
Salman Ahmadi ◽  
Saeid Homayouni
Keyword(s):  
Synthetic Aperture Radar ◽  
Change Detection ◽  
Active Contours ◽  
Training Data ◽  
Synthetic Aperture ◽  
Data Sets ◽  
Difference Image ◽  
Proposed Model ◽  
The Difference ◽  
Aperture Radar

In this paper, we propose a novel approach based on the active contours model for change detection from synthetic aperture radar (SAR) images. In order to increase the accuracy of the proposed approach, a new operator was introduced to generate a difference image from the before and after change images. Then, a new model of active contours was developed for accurately detecting changed regions from the difference image. The proposed model extracts the changed areas as a target feature from the difference image based on training data from changed and unchanged regions. In this research, we used the Otsu histogram thresholding method to produce the training data automatically. In addition, the training data were updated in the process of minimizing the energy function of the model. To evaluate the accuracy of the model, we applied the proposed method to three benchmark SAR data sets. The proposed model obtains 84.65%, 87.07%, and 96.26% of the Kappa coefficient for Yellow River Estuary, Bern, and Ottawa sample data sets, respectively. These results demonstrated the effectiveness of the proposed approach compared to other methods. Another advantage of the proposed model is its high speed in comparison to the conventional methods.

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