Parametric Optimization of Structures Under Combined Base Motion Direct Forces and Static Loading

1998 ◽  
Vol 124 (1) ◽  
pp. 132-140 ◽  
Author(s):  
Izhak Bucher
Keyword(s):  
Degrees Of Freedom ◽  
Structural Parameters ◽  
Operating Conditions ◽  
Design Parameters ◽  
Power Spectral ◽  
Loading Patterns ◽  
The Cost ◽  
Selection Of ◽  
Eigenvectors And Eigenvalues

This paper deals with the optimization of vibrating structures as a mean for minimizing unwanted vibration. Presented in this work is a method for automatic determination of a set of preselected design parameters affecting the geometrical layout or shape of the structure. The parameters are selected to minimize the dynamic response to external forcing or base motion. The presented method adjusts the structural parameters by solving an optimization problem in which the constraints are dictated by engineering considerations. Several constraints are defined so that the static deflection, the stress levels and the total weight of the structure are kept within bounds. The dynamic loading acting upon the structure is described in this work by its power spectral density, with this representation the structure can be tailored to specific operating conditions. The uncertain nature of the excitation is overcome by combining all possible spectra into one PSD encompassing all possible loading patterns. An important feature of the presented method is its numerical efficiency. This feature is essential for any reasonably sized problem as such problems are usually described by thousands of degrees of freedom arising from a finite-element idealization of the structure. In this paper, efficient, closed form expressions, for the cost function and its gradients are derived. Those are computed with a partial set of eigenvectors and eigenvalues thus increasing the efficiency further. Several numerical examples are presented where both shape optimization and the selection of discrete components are illustrated.

Design and Construction of a Dual Axis Passive Solar Tracker, for Use on Yucata´n

2011 ◽  
Author(s):  
Mari´a M. Pe´rez Sa´nchez ◽  
David Balam Tamayo ◽  
Ricardo H. Cruz Estrada
Keyword(s):  
Degrees Of Freedom ◽  
Operating Conditions ◽  
The Sun ◽  
Pv Panel ◽  
Solar Tracker ◽  
Passive Solar ◽  
The Cost ◽  
Economical Alternative ◽  
Critical Aspects

In this investigation, we propose to use the thermal expansion properties of metals in a bimetallic strip as a base of operation of a passive solar tracker. The design process involved the determination of all aspects necessary to make a first prototype based on requirements and operating conditions previously identified. Predictive mathematical models were used to decide critical aspects. Certainly, some aspects of the design were determined experimentally to ensure the proper functioning of the solar tracker. The product of this research was the construction of a prototype with the ability to be placed with an average angular difference of 25 degrees to the position of the sun, under controlled conditions. The device created is a passive solar tracker with two degrees of freedom, one used to track the sun daily, operates automatically actuated by the bimetallic strip, the other one is manually adjusted in seasonal changes to compensate the variation in the decline of the sun along the year. Although the accuracy of the system is low, the cost of production is well below the purchase price of any commercial solar tracker, and its construction is simple, making it an economical alternative to increase the production of photovoltaic energy on a PV panel currently fixed.

Determination of the minimum number of technological bases of a part

2020 ◽  
pp. 73-75
Author(s):  
B.M. Bazrov ◽  
T.M. Gaynutdinov
Keyword(s):  
Cost Price ◽  
Labor Input ◽  
Part Surface ◽  
Technological Base ◽  
Size Accuracy ◽  
Minimum Number ◽  
The Cost ◽  
Input Cost ◽  
Selection Of

The selection of technological bases is considered before the choice of the type of billet and the development of the route of the technological process. A technique is proposed for selecting the minimum number of sets of technological bases according to the criterion of equality in the cost price of manufacturing the part according to the principle of unity and combination of bases at this stage. Keywords: part, surface, coordinating size, accuracy, design and technological base, labor input, cost price. [email protected]

scholarly journals Influence of the main operating parameters on the DRPSA process design based on the equilibrium theory

Adsorption ◽  
2020 ◽  
Author(s):  
Ester Rossi ◽  
Giuseppe Storti ◽  
Renato Rota
Keyword(s):  
Pressure Swing Adsorption ◽  
Degrees Of Freedom ◽  
Pressure Ratio ◽  
Complete Separation ◽  
Operating Conditions ◽  
Equilibrium Theory ◽  
Design Parameters ◽  
Reflux Ratio ◽  
Gaseous Mixtures ◽  
Pressure Swing

Abstract Among the adsorption-based separation processes for gaseous mixtures, those exploiting pressure variations, so-called Pressure Swing Adsorption (PSA) processes, are the most popular. In this work, we focus on the specific PSA configuration known as Dual Reflux-Pressure Swing Adsorption (DR-PSA) given its ability to achieve sharp separations. In the case of binary mixtures, an analytical approach based on Equilibrium Theory has been proposed to identify the operating conditions for complete separation under the assumption of linear isotherms. This same approach is not available when the separation is not complete. Accordingly, in this work we study the features of non-complete separations by solving numerically a general DR-PSA model with parameter values suitable to approach equilibrium conditions (no mass transport resistances, no axial mixing, isothermal conditions and no pressure drop), thus reproducing the analytical solution when complete separations are examined. Even for non-complete separations, triangularly shaped regions at constant purity can be identified on a plane whose axes correspond to suitable design parameters. Moreover, we found a general indication on how to select the lateral feed injection position to limit the loss in product purities when complete separation is not established, whatever is the composition of the feeding mixture. Finally, a sensitivity analysis with respect to pressure ratio, light reflux ratio and heavy product flowrate is proposed in order to assess how to recover product purities according to the specific degrees of freedom of a DR-PSA apparatus.

scholarly journals A Computationally Efficient Multidiode Model for Optimizing the Front Grid of Multijunction Solar Cells under Concentration

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Chris H. van de Stadt ◽  
Pilar Espinet Gonzalez ◽  
Harry A. Atwater ◽  
Rebecca Saive
Keyword(s):  
Solar Cells ◽  
Operating Conditions ◽  
Design Parameters ◽  
Computationally Efficient ◽  
Fast Determination ◽  
Wide Range ◽  
Multijunction Solar Cells ◽  
Efficiency Increase ◽  
Light Concentration

We have developed a computationally efficient simulation model for the optimization of redirecting electrical front contacts for multijunction solar cells under concentration, and we present its validation by comparison with experimental literature results. The model allows for fast determination of the maximum achievable efficiency under a wide range of operating conditions and design parameters such as the contact finger redirecting capability, period and width of the fingers, the light concentration, and the metal and emitter sheet resistivity. At the example of a state-of-the-art four-junction concentrator solar cell, we apply our model to determine ideal operating conditions for front contacts with different light redirection capabilities. We find a 7% relative efficiency increase when enhancing the redirecting capabilities from 0% to 100%.

Modeling of a New Crank-Less Rotary Heat Engine Concept for Solar Power Utilization

2018 ◽  
Author(s):  
Muhammad I. Rashad ◽  
Hend A. Faiad ◽  
Mahmoud Elzouka
Keyword(s):  
Degrees Of Freedom ◽  
Unit Cost ◽  
Heat Engine ◽  
Structure Design ◽  
Operating Conditions ◽  
Design Parameters ◽  
Working Fluid ◽  
Heat Engines ◽  
And Performance ◽  
Engine Concept

This paper presents the operating principle of a novel solar rotary crank-less heat engine. The proposed engine concept uses air as working fluid. The reciprocating motion is converted to a rotary motion by the mean of unbalanced mass and Coriolis effect, instead of a crank shaft. This facilitates the engine scaling and provides several degrees of freedom in terms of structure design and configuration. Unlike classical heat engines (i.e. Stirling), the proposed engine can be fixed to the ground which significantly reduce the generation unit cost. Firstly, the engine’s configuration is illustrated. Then, order analysis for the engine is carried out. The combined dynamics and thermal model is developed using ordinary differential equations which are then numerically solved by Simulink™. The resulting engine thermodynamics cycle is described. It incorporates the common thermodynamics processes (isobaric, isothermal, isochoric processes). Finally, the system behavior and performance are analyzed along with studying the effect of various design parameters on operating conditions such as engine speed, output power and efficiency.

scholarly journals Dynamic Analysis of Noncontacting Face Seals

1982 ◽  
Vol 104 (4) ◽  
pp. 460-468 ◽  
Author(s):  
I. Etsion
Keyword(s):  
Dynamic Behavior ◽  
Degrees Of Freedom ◽  
Approximate Expression ◽  
Operating Conditions ◽  
Design Parameters ◽  
Seal Ring ◽  
Critical Stability ◽  
Dimensionless Groups ◽  
Stability Maps ◽  
Metal Bellows

The dynamic behavior of a noncontacting coned face seal is analyzed for the case of a rigidly mounted rotating seat and a flexibly mounted stationary ring taking into account various design parameters and operating conditions. The primary seal ring motion is expressed by a set of nonlinear equations for three degrees of freedom. These equations, which are solved numerically, allow identification of two dimensionless groups of parameters that affect the seal dynamic behavior. Stability maps for various seals are presented. These maps contain a stable-to-unstable transition region in which the ring wobbles at half the shaft frequency. The effect of various parameters on seal stability is discussed and an approximate expression for critical stability is offered. The theoretical model assumes frictionless flexible mounting of the seal ring such as in metal bellows. However, the results for critical stability can also be used as an upper limit for cases when friction in the secondary seal is present.

Assessment of the Effectiveness of Gas Path Diagnostic Schemes

2004 ◽  
Vol 128 (1) ◽  
pp. 57-63 ◽  
Author(s):  
K. Mathioudakis ◽  
Ph. Kamboukos
Keyword(s):  
Gas Turbines ◽  
Individual Component ◽  
Uncertainty Propagation ◽  
Data Retrieval ◽  
Operating Conditions ◽  
Small Deviations ◽  
Component Identification ◽  
Operating Points ◽  
Selection Of

A variety of methods can be used for the diagnosis of faults in gas path components of gas turbines. Problems that are common for diagnostic method implementation are the choice of measured quantities, choice of health parameters, and choice of operating conditions for data retrieval. The present paper introduces some general principles for evaluation of the effectiveness of different diagnostic schemes. They encompass criteria proposed in past publications, while they offer additional possibilities for assessment of diagnostic effectiveness in various situations. The method is based on the evaluation of the behavior of linear systems, which are a good approximation of the nonlinear ones for small deviations and employs the concept of system condition number to formulate criteria. The determination of limits for this number for establishing system condition criteria and quantification of observability is examined, on the basis of uncertainty propagation. Sample problems evaluated are: maximizing effectiveness of individual component identification from a multiplicity of available measurements, selection of individual operating points for multipoint applications.

scholarly journals TO THE DEVELOPMENT OF SOIL TILLAGE WORKING UNITS ON THE BASIS OF FIELDS SOLIDGRAMS

2018 ◽  
Vol 13 (2) ◽  
pp. 100-106 ◽  
Author(s):  
Юрий Казаков ◽  
Yuriy Kazakov ◽  
Владимир Медведев ◽  
Vladimir Medvedev ◽  
Алексей Терентьев ◽  
...  
Keyword(s):  
Degrees Of Freedom ◽  
Rational Design ◽  
Soil Tillage ◽  
Design Parameters ◽  
Factors Affecting ◽  
Rational Design Parameters ◽  
Automatic Adaptation ◽  
Cultivation Technology ◽  
Elastic Characteristics

When solving engineering problems in soil cultivation, soil resistivity is applied. The use of solidograms is more preferable in the construction of soil-working tools and the operation of agricultural machinery. The developed technologies and instruments for continuous layerwise determination of the longitudinal hardness of the arable layer make it possible to obtain soil maps by hardness, to create a database. Factors affecting hardness variability include crop cultivation technology, row spacing, parameters, number and gauge of movers of mobile power tools and agricultural tools, the width of the technological track. The influence of the degrees of freedom of the working units on the intensity of loosening of the soil, the magnitude and nature of the change in the traction resistance, both as a separate working unit and the entire implement, is considered. A combined working unit consisting of a cutaway knife, a built-in drainer, a spring bender on a spring-loaded draft, which creates conditions for the realization of low-intensity types of deformation, the Baushinger effect is proposed. The advantage of the working unit is the continuous automatic adaptation of geometric parameters. For design and strength calculation of such working units, synthesis of elastic characteristics, it is recommended to use methods of the theory of random oscillations. The force and kinematic perturbation of the oscillations is caused by the variability of the hardness of the arable layer, the speed of movement of the working organ, the vibrorheological properties of the soil, and the parameters of the elastic characteristics of the system of springs. The rationale for the smoothing capability of the dynamical system being designed is substantiated by justifying rational design parameters, selecting the material, determining the system parameters by known characteristics at the input and output.

scholarly journals Mathematical model for optimizing the fleet of vehicles for performing land reclamation works

2021 ◽  
Vol 274 ◽  
pp. 11004
Author(s):  
Talgat Gabdullin ◽  
Marat Makhmutov
Keyword(s):  
Land Reclamation ◽  
Physical Nature ◽  
Operating Conditions ◽  
Special Equipment ◽  
Technological Complex ◽  
Reliability Characteristics ◽  
Fundamental Possibility ◽  
Group Form ◽  
The Cost

When choosing technical means for performing various technological processes and, in particular, for carrying out reclamation and cultural-technical works, two aspects should be taken into account: the fundamental possibility of using machines and the level of their reliability. But if the choice of technical means according to the fundamental possibility of use for performing a specific operation is sufficiently developed («Systems of machines», catalogs of special equipment have been developed), then the choice of means of repair and technical impact, depending on quantitative data and qualitative characteristics of reliability, is currently not fully studied. This is due to the lack of a sufficient database on malfunctions of the specified technical means and, as a consequence, the lack of reliable indicators of their reliability. Analysis of the data on the operation of technical means in land reclamation and construction organizations shows that due to the low reliability of machines, up to 40% of the cost of their work is the cost of maintenance and repair, while the share of time resources for downtime for technical reasons in the total fund of the working time reaches 40-50%. It should be noted that this is only part of the damage caused by the lack of reliability of the machines. Improving the methods of using machines led to the creation of mechanized complexes - a group form of machine work. Therefore, due to the widespread use of complex mechanization in land reclamation construction, the stop of one machine of a technological complex leads to a stop of the entire technological process. Thus, the determination of the reliability characteristics of the units of technological complexes, namely, the establishment of the physical nature, failures, the identification of the causes of their occurrence, as well as the determination of the need for repair and technical actions, will provide the necessary operational and economic performance indicators of the entire technological complex in specific operating conditions. In this regard, the issue of determining the optimal provision of repair and technical impacts on the units of technological complexes, taking into account their components, is an urgent task that requires separate research.

scholarly journals AJUSTE DA EQUAÇÃO DE HAZEN-WILLIANS PARA DETERMINAÇÃO DA PERDA DE CARGA CONTÍNUA EM TUBULAÇÕES DE PVC

Irriga ◽  
2019 ◽  
Vol 1 (1) ◽  
pp. 94-100
Author(s):  
EUGENIO PACELI MIRANDA ◽  
TATIANA BELO DE SOUSA CUSTODIO ◽  
FRANCISCO UCHOA de LIMA ◽  
TAIANE ALMEIDA Pereira ◽  
ANDRE LUIZ RIBEIRO BICUDO
Keyword(s):  
Mean Absolute Error ◽  
Absolute Error ◽  
Head Loss ◽  
Fundamental Parameter ◽  
Pumping System ◽  
Pvc Pipe ◽  
The Cost ◽  
E Mail ◽  
Selection Of

AJUSTE DA EQUAÇÃO DE HAZEN-WILLIANS PARA DETERMINAÇÃO DA PERDA DE CARGA CONTÍNUA EM TUBULAÇÕES DE PVC     EUGENIO PACELI MIRANDA1; TATIANA BELO DE SOUSA CUSTODIO2; FRANCISCO UCHOA DE LIMA3; TAIANE ALMENDA PEREIRA4 E ANDRE LUIZ RIBEIRO BICUDO5   1Professor, Doutor IFCE, Campus Iguatu/CE, Rua Plácido Almino Uchoa, 60, Iguatu/Ceará. CEP: 63.500-000, Brasil, email:[email protected]; 2 Tecnólogo em Irrigação e Drenagem, IFCE, Campus Iguatu, Rodovia Iguatu-Várzea Alegre km 05, CEP: 63.500-000, Brasil, email: [email protected]; 3Graduando em Tecnologia em Irrigação e Drenagem, IFCE, Campus Iguatu, Rodovia Iguatu-Várzea Alegre km 05, CEP: 63.500-000, Brasil, e-mail: [email protected]; 4Graduandos em Tecnologia em Irrigação e Drenagem, IFCE, Campus Iguatu, Rodovia Iguatu-Várzea Alegre km 05, CEP: 63.500-000, Brasil, e-mail: [email protected]; 5 Prof. do Colégio Técnico Industrial "Prof. Isaac Portal Roldan", Unesp, Campus Bauru. Av. Eng. Luis Edmundo Carrijo Coube, 14-01, CEP: 17.033-360, Brasil, e-mail: [email protected]     1 RESUMO   A perda de carga é um parâmetro fundamental para o dimensionamento das tubulações, estando diretamente relacionada ao custo dessas tubulações, a seleção do sistema de bombeamento e o custo com o consumo de energia elétrica. Nesse estudo ajustou-se a equação de Hazen-Willians e comparou com a equação de Darcy-Weisbach. O desempenho da equação ajustada foi determinada pelo índice de concordância (c), Erro Padrão Estatístico (EPE) e o Erro Absoluto Médio (EAM). Os resultados mostram que todos os índices usados para verificar o desempenho da equação de Hazen-Willians ajustada melhoraram. A maior diferença entre os valores da perda de carga contínua entre o método de Darcy-Weisbach e a equação de Hazen-Willians ajustada ficou em torno de 0,08%, valor que pode ser considerado extremamente baixo.   Palavras-chave: Perda de carga, Darcy- Weisbach, diâmetro.     MIRANDA, E. P; CUSTODIO, T. B. S; LIMA, F. U; PEREIRA, T. A.; BICUDO, A. L. R. ADJUSTMENT OF THE HAZEN-WILLIANS EQUATION FOR DETERMINATION OF CONTINUOUS PRESSURE DROP IN PVC PIPE     2 ABSTRACT   The head loss is a fundamental parameter for the dimensioning of the pipes, being directly related to the cost of these pipes, the selection of the pumping system and the energy cost of electricity. That study fitted the Hazen-Williams equation and compared it with the Darcy-Weisbach equation. The performance of the adjusted equation was determined by the concordance index (c), Statistical Standard Error (EPE) and Mean Absolute Error (EAM). The results show that all gridded indices to verify the performance of the adjusted Hazen-Willians equation have improved. The largest difference between the values of continuous load loss between the Darcy-Weisbach method and the adjusted Hazen-Williams equation was about 0.08%, which can be considered extremely low   Keywords: Head loss, Darcy-Weisbach, diameter.

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