Constraint Manifold Synthesis of Planar Linkages

1996 ◽  
Author(s):  
A. P. Murray ◽  
J. M. McCarthy
Keyword(s):  
Design Theory ◽  
Geometric Constraints ◽  
Design Parameters ◽  
Design Problems ◽  
Constraint Manifold ◽  
Linkage Design ◽  
Versatile Tool ◽  
Algebraic Constraints ◽  
Planar Linkages

Abstract This paper formulates the design theory of planar four-bar linkages using the planar form of dual quaternions known as planar quaternions. The set of positions reachable by the floating link of a dyad is a quadratic algebraic surface called a constraint manifold. Determining the coefficients of the quadratic form defining this manifold is equivalent to setting the design parameters of the linkage. If the task of the linkage is specified as geometric constraints on the location of the floating link, then algebraic constraints are obtained on the quaternion components. We seek the coefficients of the constraint manifold that satisfies these constraints. The result is an algebraic formulation that is symmetric in its characterization of the linkage and task, and provides a versatile tool for the formulation and solution of linkage design problems.

Deflection and Stress Analysis in High Speed Planar Mechanisms With Elastic Links

1973 ◽  
Vol 95 (2) ◽  
pp. 541-548 ◽  
Author(s):  
Imdad Imam ◽  
George N. Sandor ◽  
Steven N. Kramer
Keyword(s):  
Stress Analysis ◽  
High Speed ◽  
Computation Time ◽  
Rate Of Change ◽  
Design Parameters ◽  
Planar Mechanisms ◽  
Vector Method ◽  
Linkage Design ◽  
Deflection Analysis ◽  
Planar Linkages

In the design of high speed machinery the solution of the kinematics problem alone may in certain cases not be sufficient due to the elastic nature of the mechanism parameters. A method of deflection analysis, suitable for computer programming, is presented here which is general for all planar linkages including multi-loop mechanisms. This generality is accomplished by the extension of the permutation vector method of structural analysis to the kineto-elastodynamic analysis of mechanisms and by the introduction of the rate of change of the eigenvalues with respect to the motion of mechanisms. Both of these methods are believed to be applied here for the first time in the area of linkage design. With these methods an eigenvalue problem of high order is solved whereby the required computation time is decreased by a factor of three with respect to conventional numerical methods in most cases. Furthermore a method of dynamic stress analysis is presented to indicate the relationship between the dynamic stresses and the mechanism design parameters. Several numerical examples illustrate the concepts developed in this paper.

Optimal Characterization of 28 GHz Bowtie Antenna for 5G Applications

2021 ◽  
Author(s):  
AHMET ULUSLU
Keyword(s):  
Design Optimization ◽  
Antenna Design ◽  
Microwave Antenna ◽  
Design Parameters ◽  
Design Problems ◽  
Bowtie Antenna ◽  
5G Technologies ◽  
Reliable Solution ◽  
Selection Of

Abstract Here, the selection of the design parameters of the bowtie patch antenna (BPA) for 5G applications is presented as a multidimensional, multi-purpose design optimization problem. The operating frequency of the proposed antenna is 28 GHz, which is the standard for millimeter waveband and 5G technologies. In order to overcome this difficult design optimization, a new, fast and powerful optimization algorithm was used by modified the non-dominant sorting genetic algorithm (NSGA)-III and optimal characterization of the microwave antenna design was obtained. It is assumed that the optimal characterization gives the best solution for the determined cost function, among the possible solutions within the specified range. The superiority of the proposed method has been proven by comparing it with similar types of algorithm. The antennas in the results found have good performance operating at 28 GHz, with a return loss of up to –49 dB, a gain of around 1.96 dB, good directivity, and the radiation pattern of the proposed antenna has a good match over the required frequency. Therefore, the proposed design can be used in 5G devices. As a whole, the proposed design optimization process is an efficient, fast and reliable solution for all antenna design problems.

scholarly journals Calculation Method of Permanent Deformation of Asphalt Mixture Based on Interval Number

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2116
Author(s):  
Yue Xiao ◽  
Limin Tang ◽  
Jiawei Xie
Keyword(s):  
Interval Analysis ◽  
Calculation Method ◽  
Design Theory ◽  
Permanent Deformation ◽  
Asphalt Mixture ◽  
Design Parameters ◽  
Interval Variable ◽  
Road Design ◽  
Weight Assignment ◽  
Variable Weight

There are great uncertainties in road design parameters, and the traditional point numerical calculation results cannot reflect the complexity of the actual project well. Additionally, the calculation method of road design theory based on interval analysis is more difficult in the use of uncertain design parameters. In order to simplify the calculation process of the interval parameters in the road design theory, the asphalt pavement design is taken as the analysis object, and the permanent deformation of the asphalt mixture is simplified by combining the interval analysis theory. Considering the uncertainty of the design parameters, the data with boundaries but uncertain size are expressed in intervals, and then the interval calculation formula for the permanent deformation of the asphalt mixture is derived, and the interval results are obtained. In order to avoid the dependence of interval calculation on the computer code, according to the interval calculation rule, the interval calculation method with the upper and lower end point values as point operations is proposed. In order to overcome the contradiction between interval expansion results and engineering applications, by splitting the multi-interval variable formulas, the interval variable weights are reasonably given, and the synthesis of each single interval result realizes a simplified calculation based on interval variable weight assignment. The analysis results show that the interval calculation method based on the point operation rule is accurate and reliable, and the simplified method based on the interval variable weight assignment is effective and feasible. The simplified interval calculation method proposed in this paper provides a reference for the interval application of road design theory.

scholarly journals The memory effect of nanoscale memristors investigated by conducting scanning probe microscopy methods

2012 ◽  
Vol 3 ◽  
pp. 722-730 ◽  
Author(s):  
César Moreno ◽  
Carmen Munuera ◽  
Xavier Obradors ◽  
Carmen Ocal
Keyword(s):  
Memory Effect ◽  
Scanning Probe Microscopy ◽  
Electrical Characterization ◽  
Scanning Force Microscopy ◽  
Scanning Probe ◽  
Force Microscopy ◽  
Versatile Tool ◽  
Scanning Force ◽  
Memristor Device

We report on the use of scanning force microscopy as a versatile tool for the electrical characterization of nanoscale memristors fabricated on ultrathin La0.7Sr0.3MnO3 (LSMO) films. Combining conventional conductive imaging and nanoscale lithography, reversible switching between low-resistive (ON) and high-resistive (OFF) states was locally achieved by applying voltages within the range of a few volts. Retention times of several months were tested for both ON and OFF states. Spectroscopy modes were used to investigate the I–V characteristics of the different resistive states. This permitted the correlation of device rectification (reset) with the voltage employed to induce each particular state. Analytical simulations by using a nonlinear dopant drift within a memristor device explain the experimental I–V bipolar cycles.

Electrothermal Characterization of Doped-Si Heated Microcantilevers Under Periodic Heating Operation

2016 ◽  
Vol 138 (5) ◽  
Author(s):  
Sina Hamian ◽  
Andrew M. Gauffreau ◽  
Timothy Walsh ◽  
Jungchul Lee ◽  
Keunhan Park
Keyword(s):  
Microelectromechanical Systems ◽  
Transfer Functions ◽  
Design Parameters ◽  
Periodic Heating ◽  
Element Analysis ◽  
Full Spectrum ◽  
Frequency Dependent ◽  
Thermal Transfer ◽  
Fea Model

This paper reports the frequency-dependent electrothermal behaviors of a freestanding doped-silicon heated microcantilever probe operating under periodic (ac) Joule heating. We conducted a frequency-domain finite-element analysis (FEA) and compared the steady periodic solution with 3ω experiment results. The computed thermal transfer function of the cantilever accurately predicts the ac electrothermal behaviors over a full spectrum of operational frequencies, which could not be accomplished with the 1D approximation. In addition, the thermal transfer functions of the cantilever in vacuum and in air were compared, through which the frequency-dependent heat transfer coefficient of the air was quantified. With the developed FEA model, design parameters of the cantilever (i.e., the size and the constriction width of the cantilever heater) and their effects on the ac electrothermal behaviors were carefully investigated. Although this work focused on doped-Si heated microcantilever probes, the developed FEA model can be applied for the ac electrothermal analysis of general microelectromechanical systems.

Qualitative Knowledge and Manufacturing Considerations in Multidisciplinary Structural Optimization of Hybrid Material Structures

2006 ◽  
Vol 10 ◽  
pp. 143-152 ◽  
Author(s):  
Martin Huber ◽  
Horst Baier
Keyword(s):  
Hybrid Material ◽  
Optimization Problem ◽  
Fuzzy Rule ◽  
Optimal Designs ◽  
Design Parameters ◽  
Optimization Approach ◽  
Structural Level ◽  
Design Problems ◽  
Qualitative Knowledge ◽  
Typical Design

An optimization approach is derived from typical design problems of hybrid material structures, which provides the engineer with optimal designs. Complex geometries, different materials and manufacturing aspects are handled as design parameters using a genetic algorithm. To take qualitative information into account, fuzzy rule based systems are utilized in order to consider all relevant aspects in the optimization problem. This paper shows results for optimization tasks on component and structural level.

scholarly journals A Methodology for Architecture Theory and Practices Research: Design Practices Evaluation Studio

2019 ◽  
Vol 8 (4) ◽  
pp. 195
Author(s):  
Fathi Bashier
Keyword(s):  
Knowledge Base ◽  
Design Process ◽  
Design Theory ◽  
Design Research ◽  
Future Research ◽  
Design Problems ◽  
Need To Evaluate ◽  
Research Goal ◽  
Architecture Theory ◽  
The Way

This article presents the initial findings of the design research carried out during the last semester by the master of architecture students at Wollega University, Ethiopia. The research goal is the creation of new knowledge to improve the design process. The dissatisfaction with the outcomes of the conventional design approach has led to rising concern and growing awareness of the need to evaluate design outcomes and to learn from the failure. That inadequate understanding of design problems leads frequently to design failure suggests that the evaluation of design outcomes can be made by assessing the way architects develop understanding of design problems, and how they use that understanding for developing knowledge base of the design process. The assumption is that architects’ understanding of design problems can be assessed by examining the way data is used for developing the knowledge base of the design process. The students surveyed the architects’ views in order to produce knowledge, which can be used to develop methods for discovering how inadequate data contributes to miss-informed design decisions; and methods for assessing the architects’ understanding of design problems. In this article the survey findings are analyzed and documented; and, the way the insight drawn from the inquiry can be used in future research for developing design theory, is discussed.Keywords: design outcomes, failure, evaluation, questionnaire, analyze

Design, Fabrication, and Characterization of a Soft Multi-Fingered Hand

2016 ◽  
Author(s):  
Lena Johnson ◽  
Hugh A. Bruck ◽  
Satyandra K. Gupta
Keyword(s):  
Geometric Model ◽  
Design Parameters ◽  
Experimental Setup ◽  
Robotic Hand ◽  
Iterative Design ◽  
Modeling Methods ◽  
Design And Manufacturing ◽  
Overall Performance ◽  
Fabrication And Characterization

This paper describes the design, fabrication, testing and modeling of the SUR Hand. The SUR Hand is a soft, under actuated robotic hand. Through an iterative design and manufacturing process, SUR Hand’s soft, actuating components have been adapted from the original PneuFlex, pneumatically actuated finger to be highly flexible and capable of actuating a precision force. This paper shows how altering the design parameters of the fingers altered their overall performance. Furthermore, it details the experimental setup for testing the components, as well as the modeling methods used. Finally, it shows the process for creating and validating a geometric model that characterizes proper grasping strategies, assuming a passive palm component.

scholarly journals Approximation of the index for assessing ship sea-keeping performance on the basis of ship design parameters

2007 ◽  
Vol 14 (3) ◽  
pp. 21-26 ◽  
Author(s):  
Tomasz Cepowski
Keyword(s):  
Neural Networks ◽  
Artificial Neural Networks ◽  
Ship Design ◽  
Design Parameters ◽  
Preliminary Design ◽  
Operational Effectiveness ◽  
Design Problems ◽  
New Approach ◽  
Analytical Functions ◽  
Effectiveness Index

Approximation of the index for assessing ship sea-keeping performance on the basis of ship design parameters This paper presents a new approach which makes it possible to take into account seakeeping qualities of ship in the preliminary stage of its design. The presented concept is based on representing ship's behaviour in waves by means of the so called operational effectiveness index. Presented values of the index were calculated for a broad range of design parameters. On this basis were elaborated analytical functions which approximate the index depending on ship design parameters. Also, example approximations of the index calculated by using artificial neural networks, are attached. The presented approach may find application to ship preliminary design problems as well as in ship service stage to assess sea-keeping performance of a ship before its departure to sea.

A Set-Based System for Eliminating Infeasible Designs in Engineering Problems Dominated by Uncertainty

1997 ◽  
Author(s):  
William W. Finch ◽  
Allen C. Ward
Keyword(s):  
Electronic Circuit ◽  
Predicate Logic ◽  
Software Tool ◽  
Design Parameters ◽  
Engineering Systems ◽  
Multiple Sources ◽  
Design Problems ◽  
Engineering Design Problems ◽  
Engineering Problems ◽  
Prototype Software

Abstract This paper gives an overview of a system which eliminates infeasible designs from engineering design problems dominated by multiple sources of uncertainty. It outlines methods for representing constraints on sets of values for design parameters using quantified relations, a special class of predicate logic expressions which express some of the causal information inherent in engineering systems. The paper extends constraint satisfaction techniques and describes elimination algorithms that operate on quantified relations and catalogs of toleranced or adjustable parts. It demonstrates the utility of these tools on a simple electronic circuit, and describes their implementation and test in a prototype software tool.

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