1,721,138 research outputs found
Vibration behaviors of thermally postbuckled anisotropic plates using first-order shear deformable plate theory
No full textVibration behaviors of thermally postbuckled anisotropic plates are investigated. The finite element method is used for the analysis of thermal postbuckling and natural vibration of thermally postbuckled plates. The finite element model is based on the first-order shear deformable plate theory (FSDT) and von Karman strain-displacement relation to account for large deflection. Critical buckling temperature and the corresponding mode shape are determined from Euler buckling problem. In order to solve the thermal-postbuckling problem, the initial nonlinear stiffness is determined from estimated deflection of scaled buckling mode shape. The converged deflection at any temperature change is obtained using the Newton-Raphson method. The vibration analysis of thermally postbuckled plates are performed using the tangent stiffness obtained from the converged deflection. The effect of fiber orientation angle and aspect ratio on postbuckling and vibration behaviors are studied for simply supported laminated plates subject to steady-state uniform temperature increase. (C) 1997 Elsevier Science Ltd
VIBRATION ANALYSIS OF ANISOTROPIC PLATES WITH ECCENTRIC STIFFENERS
No full textThe analysis of vibration characteristics of anisotropic plates with eccentric stiffeners has been performed using the finite element method based on the shear deformable plate theory. The stiffeners are modeled as a beam element based on Timoshenko beam theory. The present analysis presents the effects of fiber orientation, dimension and location of the stiffener on the vibration characteristics of anisotropic stiffened plates. The stiffened plates are composed of graphite-epoxy(AS1/3501-6) composite laminate with a symmetric stacking sequence. The present finite element model uses nine-node quadrilateral elements for the skin plate and three-node quadratic elements for the stiffener. The solution of the eigenvalue problems has been obtained by the subspace iteration method. The results obtained by the present finite element model are compared with previous results for the stiffened isotropic plates. Also, the result of the present beam model for the stiffener made of composite material is compared with that of the shell model. This result shows that the present model for the stiffened plate gives quite accurate results. The size, fibre orientation angle and location of the stiffener affect the natural frequencies and mode shapes of the stiffened anisotropic plate
Vibration analysis of stiffened laminated plates including thermally postbuckled deflection effect
No full textVibration characteristics of stiffened laminated plates are investigated considering postbuckled deflection effect due to thermal load. The finite element method is used for the analysis of thermal postbuckling and natural vibration of stiffened plates in the posebuckling range. The finite element model is based on the first order shear deformable plate theory (FSDT) for a skin panel and Timoshenko beam theory for stiffeners. iron Karman strain-displacement relation is used to account for a large deflection. Critical buckling temperature and the corresponding mode shape are determined from Euler buckling problem. In order to solve the thermal-postbuckling problem, the initial nonlinear stiffness is determined from an estimated deflection of scaled buckling mode shape. The converged deflection at any temperature change is obtained using the Newton-Raphson method. The vibration analyses of stiffened laminated plates in the postbuckling range are performed using the tangent stiffness obtained from the converged deflection. The effects of the stiffener size, the number of stiffeners, and lamination scheme on vibration characteristics are studied for stiffened laminated plates subject to steady-state uniform temperature increase
Supersonic flutter analysis of stiffened laminated plates subject to thermal load
No full textFlutter analysis of stiffened laminated plates has been performed. The purpose of this study is to analyze the flutter characteristics of stiffened plates subject to thermal load. The first order shear deformable plate and Timoshenko beam theories are used for the finite element modelling of a skin panel and stiffeners respectively. The von Karman non-linear strain-displacement relation is used to account for large deflections. First order piston theory is used for modelling aerodynamic loads. The Newton-Raphson iteration method and complex eigenvalue solver with the LUM/NTF approximation method are used to obtain the postbuckled deflection and flutter information respectively. The Guyan reduction method and mode tracing procedure are employed for an efficient analysis. The effects of various parameters, such as the stiffening scheme, lamination angle, boundary conditions, and temperature gradient on flutter characteristics are investigated through some numerical examples. From these examples, it can be shown that the selection of a proper stiffening scheme results in great improvements of flutter characteristics of laminated panels without introducing considerable weight penalty. (C) 1999 Academic Press
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe 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
Full text link“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
Full text linkWe 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
Controlled Decomposition Strategy for Complex Spatial Objects
No full textThis work was supported by the National Geographic Information Systems Technology
Development of the Ministry of Science and Technology of Korea
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