Predicting Changes in Vibration Behavior With Respect to Multiple Variables Using Empirical Sensitivity Functions

2010 ◽  
Vol 132 (6) ◽  
Author(s):  
Chulho Yang ◽  
Douglas E. Adams
Keyword(s):  
Empirical Data ◽  
Structural Systems ◽  
Structural Dynamic ◽  
Single Degree Of Freedom ◽  
Mass Distributions ◽  
Sensitivity Functions ◽  
Stiffness Properties ◽  
Vehicle Component ◽  
Multiple Variables ◽  
The Cost

Engineers must routinely predict how structural systems will vibrate after design modifications are made to the mass, damping, or stiffness properties of the components. To reduce the cost of product development, sensitivity prediction methods are desired that can be applied using only empirical data from an initial prototype. Embedded sensitivity functions derived solely from empirical data have previously been applied (a) to identify optimal design modifications for reducing linear vibration resonance problems and (b) to predict the change in frequency response. In this previous work, predictive methods were developed that assumed that only one design parameter in the system was modified. In many applications, it is necessary to extend this approach to all major parameters for a more accurate prediction of the structural dynamic response. This paper utilizes a multivariable Taylor series to take into account multiple parameter changes that affect a broadband frequency range. The method is applied to a single degree of freedom analytical model to determine the accuracy of the predictions. Finite element analyses are then conducted on a three-story structure and an automotive vehicle component with modifications to the stiffness and mass distributions to demonstrate the feasibility of these predictions in applications to more complicated structural systems.

Prediction of Changes in System Vibration Response Using Empirical Sensitivity Functions

2010 ◽  
Author(s):  
Chulho Yang ◽  
Douglas E. Adams
Keyword(s):  
Prediction Method ◽  
Response Prediction ◽  
System Response ◽  
Design Modification ◽  
Mass Distributions ◽  
Sensitivity Functions ◽  
Design Variables ◽  
Parameter Modification ◽  
Noise Vibration ◽  
The Cost

To improve noise, vibration, and harshness (NVH) performance in a mechanical system, engineers make changes in the mass, damping, or stiffness properties of components in the system. A system response prediction method using a sensitivity function is suggested to reduce the cost in the design modification process. Embedded sensitivity functions derived solely from empirical data have been applied to identify optimal design modifications for reducing vibration resonance problems. In this paper, those sensitivity functions are used to predict the changes in vibration behavior of a system with respect to the design parameter modification. The cost and time for building many prototypes and testing actual parts can be reduced by identifying the best parameters to be changed and determining the amount of modification in those design variables through the prediction of the system response before actual components are built. The method is applied to a single degree of freedom analytical model to study the accuracy of the predictions. Finite element analyses are then conducted on a three-story structure with modifications to the stiffness and mass distributions to demonstrate the feasibility of these predictions in applications to more complicated structural systems.

Theoretical and Numerical Analysis on the Seismic Response of Underground Structures in Existence of Isolators

2011 ◽  
Vol 368-373 ◽  
pp. 710-714
Author(s):  
Jin Chun Liu ◽  
Yi Huan
Keyword(s):  
Dynamic Response ◽  
Analytical Procedure ◽  
Axial Loading ◽  
Seismic Loading ◽  
Underground Structures ◽  
Structural Dynamic ◽  
Metro Station ◽  
Single Degree Of Freedom ◽  
Theoretical And Numerical Analysis ◽  
Elastically Supported

In this paper, an analytical method of the beam with springs and dampers fixed at the ends was proposed based on equivalent single degree of freedom (SDOF) system and secondary Lagrange’s dynamic equations, in order to develop a new effective method to enhance the aseismic capability of underground structures. The dynamic response of elastically supported and damply supported beams subjected to both seismic loading and static axial loading was analyzed by the proposed analytical procedure. The theoretical results were validated by the numerical simulation. In order to further investigate the effects of springs and dampers fixed at the ends of the columns in nonlinear response situation, the 3D nonlinear seismic responses of the Dakai metro station structure with and without the isolators were analyzed by ABAQUS respectively. It is demonstrated that: (1) the proposed analytical procedure can predict the dynamic response of beams with elastic and damper supports subjected to both seismic loading and axial loading. (2) Setting isolators at the supports of the column could enhance the aseismic capability of the structure effectively. (3) The axial static loading induced by the gravity of the soil and structure provide the constraint on the column, and therefore could not be neglected in the structural dynamic analysis.

Construction of Temporary Accommodation Camp and Selection of Optimal Type of Building

2015 ◽  
Vol 725-726 ◽  
pp. 105-110
Author(s):  
Aleksandr Birjukov ◽  
Sergey Bolotin
Keyword(s):  
Type Systems ◽  
Structural Systems ◽  
Basic Criterion ◽  
Economic Indexes ◽  
The Cost ◽  
Container Type ◽  
Selection Of ◽  
Optimal Type ◽  
Temporary Accommodation

Surveys performed nationwide show that mobile temporary accommodation camps are being manufactured by more than 200 specialized enterprises (without considering the minor manufacturers) acting under different ministries and agencies. According to the analysis performed, today 26 basic mobile structural systems consisting of 18 conveyor-type and 8 demountable-type systems are being used on a national basis. Today national manufacturers are producing more than 250 types of container-type buildings and facilities which differ in functionality, capacity, climatic category, price and other technical-and-economic indexes. Use of mobile accommodation complexes is characterized by certain advantages. Basic criterion for mobile accommodation camp construction consists in its timely commissioning. Basic predicted indexes affecting the cost of temporary accommodation camp could serve as an endorsement of the forwarded standpoint.

Classification of Occupational Safety Costs in terms of Medical Examinations in the Republic of Kazakhstan

2021 ◽  
pp. 37-42
Author(s):  
G.T. Aitkenova ◽  
Keyword(s):  
Positive Result ◽  
Empirical Data ◽  
Occupational Safety ◽  
Cost Management ◽  
Correct Classification ◽  
The Republic ◽  
The Cost ◽  
Medical Examinations ◽  
Positive Effect

The results of the study of the classification of occupational safety costs, in particular the classification of costs for medical examinations, according to the current requirements of the regulatory legal acts and documents of the Republic of Kazakhstan are presented. The Labor Code of the Republic of Kazakhstan does not regulate the cost of financing occupational safety costs in the organizations. In addition, there are no state-approved methodology for planning and occupational safety budgeting costs. International research in the field of occupational safety confirms the positive effect of the investments in occupational safety on the competitiveness, productivity, and sustainability of the enterprise at the market. At the same time, the methodologically sound organization of planning and financing of occupational safety costs depends on their correct classification, which further contributes to the construction of a rational budgetary system of the enterprise in the field of occupational safety. The need for cost classification is due to the fact, that the existing occupational safety activities have different signs and types of costs. In the process of the study the empirical data is used, for example, codes, laws, and other regulatory legal acts of the Republic of Kazakhstan, as well as the scientific research from near and far abroad. The paper offers three signs of the classification of occupational safety costs. In accordance with the proposed signs of cost classification, the types of medical examinations that employers are legally required to conduct for their employees are distributed. Thus, the classification of occupational safety costs, which is aimed at the cost management, should consider all the main options for solving managerial tasks of the enterprise in the field of occupational safety, and should be applicable in practice. At the same time, the classification of costs with varying degrees of detail contributes to the sound planning and financing of the costs for employee occupational safety, which will lead to a positive result from the investment.

scholarly journals Energy dissipation bounds for autonomous thermodynamic cycles

2020 ◽  
Vol 117 (7) ◽  
pp. 3478-3483 ◽  
Author(s):  
Samuel J. Bryant ◽  
Benjamin B. Machta
Keyword(s):  
Energy Dissipation ◽  
Energy Cost ◽  
Control Parameter ◽  
Thermodynamic Process ◽  
Stochastic Thermodynamics ◽  
Controlled System ◽  
Single Degree Of Freedom ◽  
Thermodynamic Cycles ◽  
Single Degree ◽  
The Cost

How much free energy is irreversibly lost during a thermodynamic process? For deterministic protocols, lower bounds on energy dissipation arise from the thermodynamic friction associated with pushing a system out of equilibrium in finite time. Recent work has also bounded the cost of precisely moving a single degree of freedom. Using stochastic thermodynamics, we compute the total energy cost of an autonomously controlled system by considering both thermodynamic friction and the entropic cost of precisely directing a single control parameter. Our result suggests a challenge to the usual understanding of the adiabatic limit: Here, even infinitely slow protocols are energetically irreversible.

Aseismic Structural Systems for Buildings

2006 ◽  
Vol 1 (3) ◽  
pp. 358-377 ◽  
Author(s):  
Makoto Watabe ◽  
Keyword(s):  
Simple Structure ◽  
Dynamic Properties ◽  
Time History ◽  
Structural Systems ◽  
Initial Displacement ◽  
Single Degree Of Freedom ◽  
Principal Factors ◽  
History Of ◽  
Circular Frequency ◽  
General Dynamic

When structures are subjected to earthquake motions, the principal factors controlling their behavior are i) dynamic characteristics of the structure ii) characteristics of the input earthquake motions. In this sense, it is essential, first of all, to be acquainted with general dynamic properties. Let the simple structure – single degree of freedom system – as illustrated in Fig. 1 be considered. Spring, mass, and damper are the three elements which characterize the system. If to this system, an initial displacement is applied, then set it free, the time history of the displacement, velocity and acceleration will be as shown in Fig. 2. In Fig. 2 the basic concepts of period, frequency and circular frequency of the system are also explained.

scholarly journals Professionalization tools: impact of the game-based website ‘Check your Smile’ on specialized terminology acquisition

2021 ◽  
pp. 302-306
Author(s):  
Nadia Yassine-Diab ◽  
Laura M. Hartwell ◽  
Sébastien Dejean
Keyword(s):  
Language Learning ◽  
Empirical Data ◽  
Test Scores ◽  
Vocabulary Learning ◽  
Computer Assisted ◽  
Vocabulary Test ◽  
Digital Game ◽  
Multiple Variables ◽  
Collaborative Platform ◽  
Current Area

Computer assisted vocabulary learning, i.e. specialized terminology acquisition, is a major tool to learning Languages for Specific Purposes (LSP) necessary to students’ professionalization. One current area of research is digital game-based language learning because of its motivating qualities. This paper discusses electronics students’ acquisition of specific vocabulary as related to the free game-based collaborative platform Check Your Smile (CYS), which is entirely devoted to learning LSP terminology. CYS aggregates various types of games that automatically generate individualized game plays, drawing upon a collaboratively constructed multilingual dictionary. The study focuses on multiple variables including attending a selective engineering course taught in English and the language used to teach the mandatory electronics class. Empirical data shows that students having used CYS tend to obtain better vocabulary test scores than students who did not.

scholarly journals Emerging Technologies: The cost of designing in timber.

2021 ◽  
Author(s):  
Hannah Walsh ◽  
Nilesh Bakshi ◽  
Marc Woodbury ◽  
Evzen Novak ◽  
Guy Marriage ◽  
...  
Keyword(s):  
Emerging Technologies ◽  
Structural Systems ◽  
The Cost

A comparative energy and cost based study of structural systems comprised of timber, concrete and steel

scholarly journals Emerging Technologies: The cost of designing in timber.

2021 ◽  
Author(s):  
Hannah Walsh ◽  
Nilesh Bakshi ◽  
Marc Woodbury ◽  
Evzen Novak ◽  
Guy Marriage ◽  
...  
Keyword(s):  
Emerging Technologies ◽  
Structural Systems ◽  
The Cost

A comparative energy and cost based study of structural systems comprised of timber, concrete and steel

scholarly journals High-Quality Input Choice under Uncertainty and Ambiguity: An Exploratory Study of Costa Rica's Coffee Sector

2018 ◽  
Vol 10 (5(J)) ◽  
pp. 156-166
Author(s):  
Joselyne Najera ◽  
Paula Arzadun ◽  
Monica Navarro ◽  
Martin Solis
Keyword(s):  
Undergraduate Students ◽  
Odds Ratio ◽  
Strong Increase ◽  
Business Climate ◽  
Uncertainty Condition ◽  
Choice Under Uncertainty ◽  
Random Intercept ◽  
Multiple Variables ◽  
The Cost ◽  
Coffee Sector

The purpose of the present study was to analyze the effect of multiple variables on the decision to invest in high versus regular-quality coffee production inputs. Thereby, a laboratory experiment was conducted with one hundred twenty-three undergraduate students, and posterior logistic regressions with random intercept were executed to analyze the collected data. The results showed that when there is a difference in the investment cost between a coffee of higher quality and a coffee of lower quality (regular), there is a slight increase in the odds ratio of investment in quality coffee, when going from an uncertainty condition of income to one with certainty in income of a higher quality coffee. On the other hand, when the cost is equal for both types of coffee, there is a strong increase in the odds ratio when going from an uncertainty condition to one with certainty. In addition, it was found that both the possibility of loss if there is an investment in a higher quality coffee and the ambiguity in the probability of facing a favorable business climate, reduce the odds ratio of investing in higher-quality coffee.   

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