1,721,084 research outputs found
Finite Element modelling of rotary transfer machines
No full textVibration monitoring and control are central topics for machine tools, since high vibration levels reduce the quality of machined surfaces and shorten the tool life. In order to predict potential vibration issues since the early design stage, it is necessary to implement ad hoc numerical models for modal analysis. This requires significant efforts and possible conflicts with tight production scheduling of companies. This work focuses on a specific family of rotary transfer machines for the manufacturing of parts related to lock&keys industry. It investigates the possibility to achieve an acceptable estimation of the elastodynamic behavior of the machine tools through limited modifications of the Finite Element (FE) models used for structural analysis, which are generally available in the early phases of the design process. The structural FE model of a new machine tool is implemented and validated through experimental tests performed on a prototype. Then, the elastodynamic FE model is derived and simulated. The accuracy of the numerical results will be assessed through Experimental Modal Analysis (EMA)
Numerical investigations of the effects of radiation and induced heat on unreinforced concrete.
No full textComputational Strategies for Tracing Post-Limit-Point Paths with Pure Iterative Methods
No full text In this work alternative methodologies are proposed for following post-buckling paths without the need for a complete factorization of the stiffness matrix or any factorization at all. This is achieved with two different approaches. The first employs nonlinear versions of preconditioned conjugate-like methods and the so called conjugate and secant-Newton methods have been tested. The second approach is based on the classical Newton-Raphson or modified Newton-Raphson methods, while for the linearized problem in each iteration the preconditioned Lanczos method is employed. Both methodologies combine the convergence properties of Newton-like methods and the low storage requirements of pure iterative methods by varying the storage demands for the preconditioning matrix according to the available computer storage facilities. </jats:p
Development of an Automated Process for Turbine Blade Optimisation
Get PDFIn this paper we present a fully automated procedure for turbine blade op-
timisation. Optimisation process consists of geometry parametrisation using B-splines,
mesh deformation using the dynamic mesh library in OpenFOAM, numerical simulation of
transonic flow through the blade passage and finding the feasible solutions with the
Multi-Objective Genetic Algorithm (MOGA). The process proved to be robust whether
starting the optimisation from unfeasible geometry or a conventional blade profile
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
On the Karhunen-Loeve expansion and spectral representation methods for the simulation of Gaussian stochastic fields
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