1,354,695 research outputs found
Solution of Coupled Thermoelasticity Problem in Rotating Disks
No full textThe main purpose of this dissertation is to study coupled thermoelastic behaviors in disks subjected to thermal shock loads based on the generalized and classic theories of coupled thermoelasticity. To this end, this research has been carried out in two stages. In the first stage, thermoelasticity problems in an axisymmetric rotating disk with constant thickness made of a homogeneous isotropic material are analytically solved and closed-form formulations are presented for temperature and displacement fields. Since, the analytical solution is not always feasible, the finite element (FE) method can be employed for more sophisticated coupled thermoelasticity problems. Accordingly, in the second stage of the research, a novel refined 1D finite element approach with 3D-like accuracies are developed for theories of coupled thermoelasticity. Then, the developed FE models are applied for a 3D solution of the dynamic generalized coupled thermoelasticity problem in disks. Use of the reduced models with low computational costs may be of interest in a laborious time history analysis of the dynamic problems. The obtained analytical and numerical solutions are in good agreement with the results available in the literature. It is further shown that the proposed analytical and FE methods are quite efficient with very high rate of convergence
Unified finite element approach for generalized coupled thermoelastic analysis of 3D beam-type structures, part 2: Numerical evaluations
No full textUnified finite element approach for generalized coupled thermoelastic analysis of 3D beam-type structures, part 1: Equations and formulation
No full textOn dynamic analysis of variable thickness disks and complex rotors subjected to thermal and mechanical prestresses
No full textAN ADVANCED 1D FINITE ELEMENT SOLUTION FOR THERMOELASTICITY PROBLEMS IN LAMINATED BEAMS
No full textThe main purpose of the present work is the evaluation of the effects of a number of parameters on the static and dynamic thermoelastic responses of laminated beams. In particular, the stacking sequence, the aspect-ratio, the degree of anisotropy, the boundary and loading conditions are considered as problem parameters. To this end, higher-order one-dimensional models are developed for thermoelastic analyses. Governing equations (equations of motion and energy equation) are derived in a unified manner. The developed unified formulation enables the dynamic and static classical coupled and uncoupled theories of thermoelasticity to be obtained. The equations, which are written in the weak form using the weighted residual method based on the Galerkin technique, are derived according to the Carrera Unified Formulation (CUF) and the Finite Element (FE) Method. The used methodology reduces the 3D problem to one-dimensional models that are able to provide 3D-like solutions with a relevant level of accuracy. Moreover, the classical coupled, dynamic uncoupled, quasi-static uncoupled, and steady-state uncoupled theories of thermoelasticity can be derived as particular cases
3D thermoelastic analysis of rotating disks having arbitrary profile based on a variable kinematic 1D finite element method
No full textA Novel Bone Substitute with High Bioactivity, Strength, and Porosity for Repairing Large and Load-Bearing Bone Defects.
No full textAdv. Healthcare Mater. 2019, 8, 1801298 In the initially published version of this article, the author list and affiliations were incorrect. The correct author list is as follows: Jiao Jiao Li, Colin R. Dunstan, Ali Entezari, Qing Li, Roland Steck, Siamak Saifzadeh, Ameneh Sadeghpour, John R. Field, Austin Akey, David C. Bell, Martin Vielreicher, Oliver Friedrich, Seyed-Iman Roohani-Esfahani, and Hala Zreiqat* The correct affiliation for D.C.B. is as follows: Dr. A. Akey, Prof. D. C. Bell Center for Nanoscale Systems Harvard University Cambridge, MA 02138, USA
A refined finite element method for stress analysis of rotors and rotating disks with variable thickness
No full textIn this paper, a refined finite element method (FEM) based on the Carrera unified formulation (CUF) is extended for stress analysis of rotors and rotating disks with variable thickness. The variational form of the 3D equilibrium equations is obtained using the principle of minimum potential energy and solved by this method. Employing the 1D CUF, a rotor is assumed to be a beam along its axis. In this case, the geometry of the rotor can be discretized into a finite number of 1D beam elements along its axis, while the Lagrange polynomial expansions may be employed to approximate the displacement field over the cross section of the beam. Therefore, the FEM matrices and vectors can be written in terms of fundamental nuclei, whose forms are independent of the order of the beam theories. The validity and capabilities of the presented procedure are investigated in a number of numerical examples, and some conclusions are reported and compared well with the analytical and 3D finite element solutions. The results obtained by the 1D CUF models are in close agreement with the reference solutions. Moreover, it is verified that the innovative procedure presented in this paper can be used as an accurate tool of structural analysis for complex rotors to reduce the computational costs
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe 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
No full text“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
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