scholarly journals Derivation of Universal Curves for Nonlinear Soil Consolidation with Potential Constitutive Dependences

2018 ◽  
Vol 2018 ◽  
pp. 1-15 ◽  
Author(s):  
Gonzalo García-Ros ◽  
Iván Alhama ◽  
Manuel Cánovas ◽  
Francisco Alhama
Keyword(s):  
Numerical Simulations ◽  
Characteristic Time ◽  
High Reliability ◽  
Soil Consolidation ◽  
Governing Equations ◽  
Dimensionless Groups ◽  
Degree Of Consolidation ◽  
Restrictive Hypothesis ◽  
Nonlinear Consolidation

Nonlinear consolidation scenarios, based on potential type constitutive dependences—like those proposed by Juárez-Badillo—and eliminating the more restrictive hypothesis of 1+e and dz constant, were characterized by the nondimensionalization process of the governing equations, providing the independent dimensionless groups that rule the main unknowns of interest. From these, universal curves have been depicted for both the characteristic time and the average degree of consolidation. The solutions were verified by numerical simulations and successfully compared in a case study, showing the simplicity of use of the curves and the high reliability of the solutions they provide.

scholarly journals Dimensionless characterization of the non-linear soil consolidation problem of Davis and Raymond. Extended models and universal curves

2019 ◽  
Vol 4 (1) ◽  
pp. 61-78 ◽  
Author(s):  
G. García-Ros ◽  
I. Alhama ◽  
F. Alhama
Keyword(s):  
Characteristic Time ◽  
Average Degree ◽  
Dimensionless Time ◽  
Soil Consolidation ◽  
Governing Equations ◽  
Dimensionless Groups ◽  
Non Linear ◽  
Consolidation Model ◽  
Loading Ratio

AbstractThe dimensionless groups that govern the Davis and Raymond non-linear consolidation model, and its extended versions resulting from eliminating several restrictive hypotheses, were deduced. By means of the governing equations nondimensionalization technique and introducing the characteristic time concept, both in terms of settlement and pressures, was obtained (for the most general model) that the average degree of settlement only depends on the dimensionless time while the average degree of pressure dissipation does it, additionally, on the loading ratio. These results allowed the construction of universal curves expressing the solutions of the unknowns of interest in a direct and simple way.

scholarly journals Use of discriminated nondimensionalization in the search of universal solutions for 2-D rectangular and cylindrical consolidation problems

2018 ◽  
Vol 10 (1) ◽  
pp. 209-221 ◽  
Author(s):  
Gonzalo García-Ros ◽  
Iván Alhama ◽  
Manuel Cánovas
Keyword(s):  
Characteristic Time ◽  
Average Degree ◽  
Model Following ◽  
Dimensionless Groups ◽  
Cylindrical Domains ◽  
Degree Of Consolidation ◽  
Definition Of ◽  
The Mathematical Model ◽  
Analytical Expressions

Abstract The solution to the 2-D consolidation problem, both for rectangular and cylindrical domains, has been widely studied in the scientific literature, reporting the most precise solutions in the form of analytical expressions difficult to handle for the engineer due to the high number of parameters involved. In this paper, after introducing a precise definition of the characteristic time, both this magnitude and the average degree of consolidation are obtained in terms of the least number of dimensionless groups that rule the problem. To do this, the groups are firstly derived from the dimensionless governing equations deduced from the mathematical model, following a discriminated nondimensionalization procedure which provides new groups that cannot be obtained by classical nondimensionalization. By a large number of numerical simulations, the dependences of the characteristic time and the average degree of consolidation on the new dimensionless groups have allowed to represent these unknowns graphically in the form of universal curves. This allows these quantities to be read with the least mathematical effort. A case study is solved to demonstrate the reliability and accuracy of the results.

Case Study—Failure Analysis of a Multiplexer

2016 ◽  
Author(s):  
Michael Woo ◽  
Marcos Campos ◽  
Luigi Aranda
Keyword(s):  
Failure Analysis ◽  
High Reliability ◽  
Component Failure ◽  
Root Cause ◽  
Knowing That ◽  
Cause Of Failure ◽  
The Cost

Abstract A component failure has the potential to significantly impact the cost, manufacturing schedule, and/or the perceived reliability of a system, especially if the root cause of the failure is not known. A failure analysis is often key to mitigating the effects of a componentlevel failure to a customer or a system; minimizing schedule slips, minimizing related accrued costs to the customer, and allowing for the completion of the system with confidence that the reliability of the product had not been compromised. This case study will show how a detailed and systemic failure analysis was able to determine the exact cause of failure of a multiplexer in a high-reliability system, which allowed the manufacturer to confidently proceed with production knowing that the failure was not a systemic issue, but rather that it was a random “one time” event.

scholarly journals Finite Element Study on Calculation of Nonlinear Soil Consolidation Using Compression and Recompression Indexes

2020 ◽  
Vol 10 (14) ◽  
pp. 4737
Author(s):  
Chao Xu ◽  
Suli Pan
Keyword(s):  
Finite Element ◽  
Case History ◽  
Time Dependent ◽  
Discrete Equation ◽  
Soil Consolidation ◽  
Coefficient Of Consolidation ◽  
Finite Element Study ◽  
Nonlinear Consolidation ◽  
Element Study

The coefficient of consolidation is traditionally considered as a constant value in soil consolidation calculations. This paper uses compression and recompression indexes to calculate the solution-dependent nonlinear compressibility, thus overconsolidation and normal consolidation are separated during the calculations. Moreover, the complex nonlinear consolidation can be described using the nonlinear compressibility and a nonlinear permeability. Then, the finite element discrete equation with consideration of the time-dependent load is derived, and a corresponding program is developed. Subsequently, a case history is conducted for verifying the proposed method and the program. The results show that the method is sufficiently accurate, indicating the necessity of considering nonlinearity for consolidation calculations. Finally, three cases are compared to reveal the importance of separating the overconsolidation and normal consolidation. Overall, this study concluded that it is inadequate to consider just one consolidation status in calculations, and that the proposed method is more reasonable for guiding construction.

Understanding Immiscible Natural Gas Huff-N-Puff Seepage Mechanism in Porous Media: A Case Study of CH4 Huff-N-Puff by Laboratory Numerical Simulations in Chang-7 Tight Core

2021 ◽  
Vol 30 (3) ◽  
pp. 2397-2411
Author(s):  
Taiyi Zheng ◽  
Zhengming Yang ◽  
Xiangui Liu ◽  
Yutian Luo ◽  
Qianhua Xiao ◽  
...  
Keyword(s):  
Porous Media ◽  
Natural Gas ◽  
Numerical Simulations

Impact of Carotid Stent Cell Design on Vessel Scaffolding: A Case Study Comparing Experimental Investigation and Numerical Simulations

2011 ◽  
Vol 18 (3) ◽  
pp. 397-406 ◽  
Author(s):  
Michele Conti ◽  
Denis Van Loo ◽  
Ferdinando Auricchio ◽  
Matthieu De Beule ◽  
Gianluca De Santis ◽  
...  
Keyword(s):  
Experimental Investigation ◽  
Numerical Simulations ◽  
Cell Design ◽  
Carotid Stent

scholarly journals Surveillance, anticipation and firefighting: Perspectives of patient safety from a New Zealand case study

2020 ◽  
Author(s):  
J Wailling ◽  
Brian Robinson ◽  
M Coombs
Keyword(s):  
Health Care ◽  
Patient Safety ◽  
New Zealand ◽  
Health Care Professionals ◽  
Nuclear Power ◽  
High Reliability ◽  
Health Care Systems ◽  
Tertiary Hospital ◽  
Structured Interviews

© 2018 John Wiley & Sons Ltd Aim: This study explored how doctors, nurses and managers working in a New Zealand tertiary hospital understand patient safety. Background: Despite health care systems implementing proven safety strategies from high reliability organisations, such as aviation and nuclear power, these have not been uniformly adopted by health care professionals with concerns raised about clinician engagement. Design: Instrumental, embedded case study design using qualitative methods. Methods: The study used purposeful sampling, and data was collected using focus groups and semi-structured interviews with doctors (n = 31); registered nurses (n = 19); and senior organisational managers (n = 3) in a New Zealand tertiary hospital. Results: Safety was described as a core organisational value. Clinicians appreciated proactive safety approaches characterized by anticipation and vigilance, where they expertly recognized and adapted to safety risks. Managers trusted evidence-based safety rules and approaches that recorded, categorized and measured safety. Conclusion and Implications for Nursing Management: It is important that nurse managers hold a more refined understanding about safety. Organisations are more likely to support safe patient care if cultural complexity is accounted for. Recognizing how different occupational groups perceive and respond to safety, rather than attempting to reinforce a uniform set of safety actions and responsibilities, is likely to bring together a shared understanding of safety, build trust and nurture safety culture.

Crisis Compliance

2011 ◽  
pp. 137-150
Author(s):  
Laura Lally
Keyword(s):  
Hurricane Katrina ◽  
Crisis Management ◽  
High Reliability ◽  
High Reliability Organizations ◽  
Appropriate Use

This article develops the concept of crisis compliance (CC)—defined as making appropriate use of IT, and non-IT methodologies to predict, prevent, and prevail over disasters. CC emerges from Lally’s Target Shield and Weapon Model, which is grounded in the theories of crisis management, normal accident theory, and high reliability organizations. CC is then applied to a case study involving Hurricane Katrina, with examples drawn from other recent disasters. Emerging IT-based crisis management initiatives will be examined with an emphasis on how the impacts of Hurricane Katrina could have been mitigated. Recommendations for predicting, preventing, and prevailing over future disasters will emerge from the analysis.

Effect of Axial Gap between Diffuser Inlet and Impeller on Efficiency and Flow Pattern of Centrifugal Fans

2013 ◽  
Vol 446-447 ◽  
pp. 621-625
Author(s):  
Mojtaba Gholamian ◽  
Gurram Krishna Mohan Rao ◽  
Bhramara Panitapu
Keyword(s):  
Numerical Simulations ◽  
Flow Pattern ◽  
Squirrel Cage ◽  
Centrifugal Fans ◽  
And Performance

Inlet is one of the basic elements of squirrel cage fan that can have great effect on performance and losses, especially between inlet exit and first section of impeller width. In this paper the effect of axial gap between inlet diffuser and impeller on performance and flow pattern is considered. Three diffuser inlet sizes with respect to impeller size (smaller, nearly same and bigger than inner impeller diameter) and three axial gaps within the available dimensions of the casing and impeller were chosen. Numerical simulations were performed to find the effect of this axial gap on flow pattern, performance and efficiency. From the simulation of each case study, flow pattern and its mechanism and the causes that affecting the efficiency and performance due to axial gap are analyzed and presented.

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