Variability Analysis of Modal Characteristics of Frequency-Dependent Visco-Elastic Three-Layered Sandwich Beams With Spatial Random Geometrical and Material Properties

2017 ◽  
Vol 139 (6) ◽  
Author(s):  
Frédéric Druesne ◽  
Mohamed Hamdaoui ◽  
Qi Yin ◽  
El Mostafa Daya
Keyword(s):  
Random Fields ◽  
Loss Factor ◽  
Natural Frequencies ◽  
Sandwich Beam ◽  
Frequency Dependent ◽  
Geometrical Properties ◽  
Variability Analysis ◽  
Output Variability ◽  
The Face ◽  
The Impact

Material and physical properties of a frequency-dependent visco-elastic sandwich beam are modeled as a set of spatial random fields and represented by means of the Karhunen–Loève expansion. Variability analysis of frequency and loss factor are performed. An efficient approach based on modal stability procedure (MSP) is used, the so-called Monte Carlo simulation (MCS)–MSP method. The latter provides very reliable results and allows to analyze the impact of the input variability of a high number of random spatial quantities on the output response. The effect of independent and correlated couples of spatial random fields is investigated. It is shown that the output variability is generally more important for damping than for natural frequencies. Moreover, it is demonstrated that the input variability in geometrical properties are the most impacting for damping and frequency. The influence of input coefficient of variation on output variability is also studied. It is shown that a negative correlation between the face and core thicknesses result in high levels of output variability, when one parameter increases as the other decreases.

scholarly journals Nonlinear Dynamics of an Electrorheological Sandwich Beam with Rotary Oscillation

2012 ◽  
Vol 2012 ◽  
pp. 1-17 ◽  
Author(s):  
Kexiang Wei ◽  
Wenming Zhang ◽  
Ping Xia ◽  
Yingchun Liu
Keyword(s):  
Dynamic Characteristics ◽  
Loss Factor ◽  
Natural Frequencies ◽  
Multiple Scales ◽  
Parametric Instability ◽  
Sandwich Beam ◽  
The Finite Element Method ◽  
Rotating Beam ◽  
Flexible Beams ◽  
Instability Regions

The dynamic characteristics and parametric instability of a rotating electrorheological (ER) sandwich beam with rotary oscillation are numerically analyzed. Assuming that the angular velocity of an ER sandwich beam varies harmonically, the dynamic equation of the rotating beam is first derived based on Hamilton's principle. Then the coupling and nonlinear equation is discretized and solved by the finite element method. The multiple scales method is employed to determine the parametric instability of the structures. The effects of electric field on the natural frequencies, loss factor, and regions of parametric instability are presented. The results obtained indicate that the ER material layer has a significant effect on the vibration characteristics and parametric instability regions, and the ER material can be used to adjust the dynamic characteristics and stability of the rotating flexible beams.

scholarly journals Vibration Characteristics Research of Sandwich Structure with Octet-truss Lattice Core

2021 ◽  
Vol 2125 (1) ◽  
pp. 012059
Author(s):  
Nan Wei ◽  
Hongling Ye ◽  
Xing Zhang ◽  
Jicheng Li ◽  
Boshuai Yuan
Keyword(s):  
Natural Frequencies ◽  
Sandwich Beam ◽  
Vibration Characteristics ◽  
Thin Sheets ◽  
Truss Core ◽  
Octet Truss ◽  
The Face ◽  
Lattice Core ◽  
Truss Member ◽  
Good Agreement

Abstract Lattice sandwich beams are often subjected to vibrations when they are used. The aim of this study was to explore the vibration characteristics of the octet-truss lattice core sandwich beam by translating discrete octet-truss core to the continuous homogenization material. The natural frequencies of which are obtained by theoretical calculation and numerical simulation. The theoretical solutions are in good agreement with the numerical results. It demonstrates that the theoretical approach is effective to compute the natural frequency. Furthermore, the influences of truss member radius and thin sheets ply on the natural frequencies are also discussed. The outcomes indicate that the octet-truss lattice core sandwich beam’s natural frequencies are controlled via selecting the appropriate truss member radius and the face sheets thickness.

Particularities of the independent auditor's report on reliability of accounting (financial) statements for 2019: COVID-19 as qualitatively essential information (Part 2)

2020 ◽  
Vol 23 (7) ◽  
pp. 777-799
Author(s):  
O.I. Shvyreva ◽  
Z.I. Kruglyak ◽  
A.V. Petukh
Keyword(s):  
Financial Reporting ◽  
Financial Statements ◽  
Economic Situation ◽  
Risk Disclosure ◽  
Essential Information ◽  
Logical Method ◽  
Annual Reporting ◽  
The Face ◽  
Key Aspects ◽  
The Impact

Subject. This article discusses the issues related to the practice of financial reporting in the face of uncertainties caused by the coronavirus contagion, as well as the specifics of the audit strategy and formation of an audit opinion on this reporting. Objectives. The article aims to identify the quality characteristics of financial reporting prepared in the context of the COVID-19 pandemic and justify the key aspects of assurance engagement completion in an extremely uncertain epidemiological and economic situation. Methods. For the study, we used an abstract-logical method, content analysis techniques, systematization, and classification. Results. Analyzing the impact of the extremely uncertain epidemiological and economic situation on financial statements, the article clarifies aspects of disclosure of events after the reporting date and threats to business continuity in the annual reporting of economic entities. The article identifies possible alternative procedures and algorithms to obtain proper evidence when it is insufficient in the face of the inability to meet certain audit standards requirements in a remote audit environment. The article defines the impact of COVID-19 risk disclosure on the structure of the audit report and opinion. Relevance. The results of the study can be used in the practical activities of economic entities that prepare financial statements in the face of significant uncertainty, as well as auditors and audit organizations.

Safe development of business and national economy in the face of a pandemic and global recession

2020 ◽  
Vol 16 (6) ◽  
pp. 1182-1198
Author(s):  
I.V. Vyakina
Keyword(s):  
Economic Security ◽  
Global Recession ◽  
Graphical Visualization ◽  
National Economic ◽  
Business Support ◽  
The Face ◽  
The Russian Federation ◽  
Business Entities ◽  
Visualization Techniques ◽  
The Impact

Subject. This article deals with the issues related to the national economic security of the State in today's conditions. Objectives. The article aims to develop a set of special measures for additional business support to reduce the impact of restrictions imposed against the background of quarantine and the pandemic spread, and which would help prevent collapse of business entities. Methods. For the study, I used the methods of theoretical, systems, logical, and comparative analyses, and tabular and graphical visualization techniques. Results. The article proposes possible measures to support business aimed at reducing the costs of business entities due to the restrictions caused by the pandemic, that complement and explain the activities proposed by the President and Government of the Russian Federation, taking into account the regional and municipal levels. Conclusions. The uncertain current situation requires constant adjustment and adaptation of public policy in accordance with specific circumstances. Ensuring the country's economic security and sustainability associates with creation of a business organization system that connects public administration tools and business support and development opportunities under the changed environment.

The Impact of Terrorism on Construction Industry in Iraq

2015 ◽  
Vol 3 (2) ◽  
pp. 69-84
Author(s):  
Wadhah Amer Hatem ◽  
Samiaah M. Hassen Al-Tmeemy
Keyword(s):  
Construction Industry ◽  
Construction Projects ◽  
Historical Data ◽  
Terrorist Attacks ◽  
Construction Sector ◽  
Statistical Procedures ◽  
Qualitative Approaches ◽  
Suicide Attacks ◽  
The Face ◽  
The Impact

     Suicide attacks, bombings, explosions became the part of daily life in Iraq. Consequently, the threat of terrorism put the Iraqi construction sector in the face of unique and unusual challenges that not seen on other countries. These challenges can have extensive impact on construction projects. This paper seeks to examine the impact of the terrorist attacks on construction industry and determine the extent to which the impact of terrorism on construction projects in terms of cost, schedule, and quality. This study adapted quantitative and qualitative approaches to collect data using questionnaire survey and interviews, as well as historical data. The study focused on projects that have been the target of terrorist strikes in Diyala governorate. A variety of statistical procedures were employed in data analysis. The results revealed the extent to which terrorist attacks impact construction projects in terms of cost, time, and quality. The results of this study will enhance the awareness of all construction parties to the impact of the terrorist attacks against construction projects. Eventually, this can develop a risk management assessment and assist contractors to properly protect projects and buildings to minimize injuries and fatalities in the event of terrorism.

Impact of Chatbot in Transforming the Face of Retailing- An Empirical Model of Antecedents and Outcomes

2019 ◽  
Vol 12 ◽  
Author(s):  
Kumari Anshu ◽  
Loveleen Gaur ◽  
Arun Solanki
Keyword(s):  
Research Work ◽  
Shopping Behavior ◽  
Model Framework ◽  
Shopping Experience ◽  
The Face ◽  
Strongly Agree ◽  
Different Characteristics ◽  
Work Done ◽  
The Impact ◽  
Self Administered Questionnaire

Chatbot has emerged as a significant resolution to the swiftly growing customer caredemands in recent times. Chatbot has emerged as one of the biggest technological disruption. Simply speaking, it is a software agent facilitating interaction between computers and humans in natural language. So basically, it is a simulated, intellectual dialogue agent functional in a range of consumer engagement circumstances. It is the easiest and simplest means enable interaction between the retailers and the customers. </p><p> • Purpose- Most of the research work done in this field is concerned with their technical aspects. The recent research on chatbot pay little attention to the impact it is creating on users’ experience. Through this work, author is making an effort to know the customer-oriented impact that the chatbot bear on the shoppers. The purpose of this study is to develop and empirically test a framework that identify the customer oriented attributes of chatbot and impact of these attributes on customers. </p><p> • Objectives- The study intends to bridge the gap between concepts and actual attributes and applications on the subject of Chatbot. The following research objectives can address the various aspects of Chatbot affecting the different characteristics of consumers shopping behaviors: a) Identify the various attributes of chatbot that bears an impression on consumer shopping behavior. b) Evaluate the impact of chatbot on consumer shopping behavior that leads to the development of chatbot usage and adoption among the customer. </p><p> • Design/Methodology/Approach – For the purpose of analysis, author has administered Factor analysis and Multiple regression using SPSS version 23 for identification of various attributes of Chatbot and knowing their impact on shoppers. A self-administered questionnaire from the review of literature is developed. Industry experts in the field of retailing and academician evaluate the questionnaire. Primary information from the respondents is gathered using this questionnaire. The questionnaire comprises of Likert scale on a scale of 1 to 5 where 1 stands for strongly disagree and 5 stands for strongly agree. Data is collected from 126 respondents, out of which 111 respondents were finally considered for study and analysis purpose. </p><p> • Findings – The empirical results show that the study identifies various attributes of chatbot like Trust, Usefulness, Satisfaction, Readiness to Use and Accessibility. It is also found that chatbot is really influencing the customers in providing them with shopping experience, which can be very helpful to the businesses for increasing the sales and creating repurchase intention among the customers. </p><p> • Originality/value – The recent research on chatbot pay little attention to the impact it is creating on customers who are actually interacting with it on regular basis. The research paper extends information for understanding and appreciating the customer oriented attributes of artificially intelligent Chatbot. In this regard, the author has developed a model framework and proposed the attributes identified. Through the work, author is also making an effort to test empirically the impact of the identified attributes on the shoppers.

Dynamic model for high-speed rotors based on their experimental characterization

2017 ◽  
Vol 2 (4) ◽  
pp. 25
Author(s):  
L. A. Montoya ◽  
E. E. Rodríguez ◽  
H. J. Zúñiga ◽  
I. Mejía
Keyword(s):  
Dynamic Model ◽  
High Speed ◽  
Natural Frequencies ◽  
Mode Shapes ◽  
Experimental Characterization ◽  
Rotating Systems ◽  
Computing Performance ◽  
The Impact ◽  
Stiffness Distribution ◽  
Good Agreement

Rotating systems components such as rotors, have dynamic characteristics that are of great importance to understand because they may cause failure of turbomachinery. Therefore, it is required to study a dynamic model to predict some vibration characteristics, in this case, the natural frequencies and mode shapes (both of free vibration) of a centrifugal compressor shaft. The peculiarity of the dynamic model proposed is that using frequency and displacements values obtained experimentally, it is possible to calculate the mass and stiffness distribution of the shaft, and then use these values to estimate the theoretical modal parameters. The natural frequencies and mode shapes of the shaft were obtained with experimental modal analysis by using the impact test. The results predicted by the model are in good agreement with the experimental test. The model is also flexible with other geometries and has a great time and computing performance, which can be evaluated with respect to other commercial software in the future.

Moral Responsibility, Socially Embedded

2018 ◽  
Author(s):  
Lisa Herzog
Keyword(s):  
Social Psychology ◽  
Moral Responsibility ◽  
Moral Agency ◽  
Human Behaviour ◽  
Shared Responsibility ◽  
The Face ◽  
Moral Theorizing ◽  
The Impact

This chapter asks whether we can hold on to the picture of the morally responsible subject as we knew it in the face of evidence from social psychology about the impact of contexts on human behaviour. Some theorists have taken this to present a major challenge to moral theorizing. However, the chapter argues that, while we should acknowledge the malleability of human behaviour, we should not give up the notion of responsible agency. Rather, we need to broaden our theoretical horizon in order to include individuals’ co-responsibility for the contexts in which they act. This argument is a general one, but it is of particular relevance for organizations: it is our shared responsibility to turn them into contexts in which moral agency is supported rather than undermined.

scholarly journals Aspects of Strength Testing of Tank Containers in Compliance with the Requirements of the UN Navigation Rules and Regulations

2021 ◽  
Vol 9 (3) ◽  
pp. 349
Author(s):  
Andrii Sulym ◽  
Pavlo Khozia ◽  
Eduard Tretiak ◽  
Václav Píštěk ◽  
Oleksij Fomin ◽  
...  
Keyword(s):  
Natural Frequencies ◽  
Response Spectrum ◽  
Experimental Curve ◽  
Bulk Liquid ◽  
Frequency Range ◽  
Test Configuration ◽  
Shock Response ◽  
Shock Response Spectrum ◽  
Spectrum Curve ◽  
The Impact

This article deals with the method of computer-aided studies of the results of tank container impact tests to confirm the ability of portable tanks and multi-element gas containers to withstand the impact in the longitudinal direction on a specially equipped test rig or using a railway flat car by impacting a flat car with a striking car, in compliance with the requirements of the UN Navigation Rules and Regulations. It is shown that the main assessed characteristic of the UN requirements is the spectrum of the shock response (accelerations) for the interval natural frequencies of the shock pulse. The calculation of the points of the shock response spectrum curve based on the test results is reproduced in four stages. A test configuration of the impact testing of the railway flat car with a tank container is presented, and the impact is performed in such a way that, under a single impact, the shock spectrum curve obtained during the tests for both fittings subjected to impact repeats or exceeds the minimum shock spectrum curve for all frequencies in the range of 2 Hz to 100 Hz. Formulas for determining the relative displacements and accelerations for the interval natural frequencies of the shock wave are given. The research results are presented in graphical form, indicating that the experimental values of the shock response spectrum exceed the minimum permissible values; the equation of the experimental curve of the shock response spectrum in the frequency range 0–100 Hz is described by power-law dependence. The coefficients of the equation were determined by the statistical method of maximum likelihood with the determination factor being 0.897, which is a satisfactory value; a comparative analysis showed that the experimental curve of the impact response spectrum in the frequency range 0–100 Hz exceeds the normalized curve, which confirms compliance with regulatory requirements. A new test configuration is proposed using a tank car with a bulk liquid, the processes in which upon impact differ significantly from other freight wagons under longitudinal impact loads of the tank container. The hydraulic impact resulting from the impact on the tank container and the platform creates an overturning moment that causes the rear fittings to be unloaded.

scholarly journals Are public health measures and individualised care compatible in the face of a pandemic? A national observational study of bereaved relatives’ experiences during the COVID-19 pandemic

2021 ◽  
pp. 026921632110198
Author(s):  
Catriona R Mayland ◽  
Rosemary Hughes ◽  
Steven Lane ◽  
Tamsin McGlinchey ◽  
Warren Donnellan ◽  
...  
Keyword(s):  
Public Health ◽  
Family Support ◽  
Online Survey ◽  
Free Text ◽  
Professional Networks ◽  
Dying Patients ◽  
The Face ◽  
Individualised Care ◽  
The Impact ◽  
Informative Communication

Background: COVID-19 public health restrictions have affected end-of-life care experiences for dying patients and their families. Aim: To explore bereaved relatives’ experiences of quality of care and family support provided during the last days of life; to identify the impact of factors associated with perceived support. Design: A national, observational, open online survey was developed and disseminated via social media, public fora and professional networks (June–September 2020). Validated instruments and purposively designed questions assessed experiences. Analysis used descriptive statistics, logistic regression and thematic analysis of free-text responses. Participants: Individuals (⩾18 years) who had experienced the death of a relative/friend (all care settings) within the United Kingdome during the COVID-19 pandemic. Results: Respondents ( n = 278, mean 53.4 years) tended to be female ( n = 216, 78%); over half were ‘son/daughter’ (174, 62.6%) to the deceased. Deceased individuals (mean 81.6 years) most frequently died in their ‘usual place of care’ ( n = 192, 69.3%). Analysis established five conceptual themes affecting individualised care: (1) public health restrictions compounding the distress of ‘not knowing’; (2) disparate views about support from doctors and nurses; (3) challenges in communication and level of preparedness for the death; (4) delivery of compassionate care; (5) emotional needs and potential impact on grief. Male respondents (OR 2.9, p = 0.03) and those able to visit (OR 2.2, p = 0.04) were independently associated with good perceptions of family support. Conclusion: Despite public health restrictions, individualised care can be enabled by proactive, informative communication; recognising dying in a timely manner and facilitating the ability to be present before death.

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