2,134 research outputs found
A new generation 99 line Matlab code for compliance Topology Optimization and its extension to 3D
Compact and efficient Matlab implementations of compliance Topology
Optimization (TO) for 2D and 3D continua are given, consisting of 99 and 125
lines respectively. On discretizations ranging from to
elements, the 2D version, named top99neo, shows speedups from
2.55 to 5.5 times compared to the well-known top88 code (Andreassen-etal 2011).
The 3D version, named top3D125, is the most compact and efficient Matlab
implementation for 3D TO to date, showing a speedup of 1.9 times compared to
the code of Amir-etal 2014, on a discretization with elements.
For both codes, improvements are due to much more efficient procedures for the
assembly and implementation of filters and shortcuts in the design update step.
The use of an acceleration strategy, yielding major cuts in the overall
computational time, is also discussed, stressing its easy integration within
the basic codes.Comment: 17 pages, 8 Figures, 4 Table
Revisiting topology optimization with buckling constraints
We review some features of topology optimization with a lower bound on the
critical load factor, as computed by linearized buckling analysis. The change
of the optimized design, the competition between stiffness and stability
requirements and the activation of several buckling modes, depending on the
value of such lower bound, are studied. We also discuss some specific issues
which are of particular interest for this problem, as the use of non-conforming
finite elements for the analysis, the use of inconsistent sensitivities in the
optimization and the replacement of the single eigenvalue constraints with an
aggregated measure. We discuss the influence of these practices on the
optimization result, giving some recommendations.Comment: 15 pages, 12 figures, 2 table
Bussy Saint-Georges à Marne la Vallée, ou un urbanisme par images
L'histoire récente de Bussy Saint-Georges, l'une des douze communes qui composent le "secteur 3" de la Ville Nouvelle de Marne-la-Vallee, peut être considerée emblematique de la façon dont le grand projet de l'Etat de créer une série de nouvelles centralités en Ile-de-France a dû se confronter à la resistance des territoires. Cependant, Bussy n'a pas été caracterisée par l'immobilisme dont ont fait preuve les autres communes du Secteur 3. Elle représente plutôt l'histoire de comment les élus locaux, en utilisant de façon démagogique le thème du «local» incarné par des formes architecturales neo-traditionnalistes, ont réussi à s'imposer face au pouvoir central. Le concept originaire de "nouvelles centralités" qui animait le projet de l'Etat, reduit à une image de soi-meme, a été perverti en une série de micro-centralités souvent autoreferentielles et deconnectées de toute logique metropolitaine ou regionale.Bussy Saint Georges is one of the twelve municipalities making up the «secteur 3» of the new town of Marne-la-Vallée. Its recent history can be considered emblematic of how the State great project of creating new centralities in Ile-de-France (villes nouvelles) had to face the resistance of territories. However Bussy hasn¿t been characterized by the ultraconservative policy, typical of the neighboring municipalities. It represents instead the story of how local councilors, by using demagogically the theme of the «local» embodied in a «neo traditional» architectural style, achieved to impose to a central government. The original concept of «new centralities» of the State project, reduced to an image of itself, has been perverted into a series of «microcentralities», disconnected from any regional or metropolitan consistency.La historia reciente de Bussy Saint-Georges, uno de los doce municipios que componen el "sector 3" de la Ville Nouvelle de Marne-la-Vallée, puede ser considerada emblemática en tanto en cuanto el gran proyecto de Estado de crear una serie de nuevas centralidades en Île-de-France ha debido enfrentarse con la resistencia de los territorios. Sin embargo, Bussy no se ha caracterizado por el inmovilismo que han practicado los otros municipios del Sector 3. Su caso representa más bien la historia de cómo los políticos locales, utilizando demagógicamente el tema de "lo local" encarnado por formas arquitectónicas neotradicionalistas, han conseguido imponerse sobre el poder central. El concepto originario de "nuevas centralidades" que guiaba el proyecto del Estado, reducido a una imagen de sí mismo, ha sido pervertido en una serie de micro-centralidades a menudo autorreferenciadas y desconectadas de toda lógica metropolitana o regional
Le populisme esthétique. L'architecture comme outil identitaire
International audienceTout projet populiste procède par exclusion, en ceci qu’il vise à construire un espace à la fois défensif et identitaire. Comment l’architecture peut-elle devenir productrice (et victime) de ce type de montage, structuré autour de l’instrumentalisation politique de la ville? Les thuriféraires de la postmodernité prétendent que l’hétérogénéité esthétique, supposée faire pièce à l’uniformité moderniste, est l’effet de la «démocratisation des goûts». En observant la déclinaison néolibérale de ce thème à partir des années 1980, cet essai montre que le populisme esthétique, sous des dehors antimodernistes, cache une vocation éminemment inégalitaire et «sur-moderne»
Morte, natura e tecnica
In this paper the author intends to examine, within the continental philosophical tradition, the developments of the idea of death, its transformation from a collective event into an individual one, its slow detachment from the religious ambit, and its introduction in the dimension of technique
Lightweight Metal/Polymer/Metal Sandwich Composites for Automotive Applications
Sandwich composites are becoming increasingly popular in the automotive sector as they are lightweight and facilitate noise attenuation. However, given that sandwich composites are relatively new in the sector, there are questions as to whether they can effectively replace monolithic metals and damping patches without compromising mechanical performance. Quiet Aluminum®, a sandwich composite produced by Material Sciences Corporation (MSC), employs as skins two aluminum alloys that are common in automotive manufacturing: 5754-O and 6061-T4. The current study examines and compares the mechanical properties of Quiet Aluminum® with the main Fiat Chrysler Automobiles (FCA) requirements for laminates with non-structural loads. The adhesion mechanism between the layers of the sandwich composites received was examined through: T-Peel test, roughness measurements and metallographic cross sectioning technique. The current study then employed tensile tests with different treatments applied to the sandwich materials, a Self-Piercing Riveting (SPR) joining evaluation, and hardness tests on the core section of the aluminum skins. The samples, which presented rolling mill-finish surface roughness �� range of 0.46−0.56 ��, met the FCA adhesion requirements with adhesive failure mode even after the paint bake-cycle simulation (20 ��� at 185℃) and the hardening treatment applied on the sandwich with AA6061-T4 skin (1ℎ at 200℃ ). The tensile properties, computed simulating stamping process (2% pre-applied strain), the paint-bake cycle and the hardening treatment were comparable to the monolithic ones. Finally, SPR technique, evaluated through lap shear test and macro-graphic measurements, successfully joined Quiet Aluminum® samples (1.06 �� thickness) with structural High Strength Low Alloy steel (����,1.8 �� thickness and 340 ��� minimum yield strength)
The Development of Political Institutions
While the literature on “new institutionalism” explains the stability of institutional arrangements within countries and the divergence of paths of institutional development between countries, Federico Ferrara takes a “historical institutionalist” approach to theorize dynamic processes of institutional reproduction, institutional decay, and institutional change in explaining the development of political institutions. Ferrara synthesizes “power-based” or “power-distributional” explanations and “ideas-based” “legitimation explanations.” He specifies the psychological “microfoundations” of processes of institutional development, drawing heavily from the findings of experimental psychology to ensure that the explanation is grounded in clear and realistic assumptions regarding human motivation, cognition, and behavior. Aside from being of interest to scholars and graduate students in political science and other social-scientific disciplines whose research concentrates on the genesis of political institutions, their evolution over time, and their impact on the stability of political order and the quality of governance, the book will be required reading in graduate courses and seminars in comparative politics where the study of institutions and their development ranks among the subfield’s most important subjects
The Bus Goes Wireless: Routing-Free Data Collection with QoS Guarantees in Sensor Networks
Abstract—We present the low-power wireless bus (LWB), a new communication paradigm for QoS-aware data collection in lowpower sensor networks. The LWB maps all communication onto network floods by using Glossy, an efficient flooding architecture for wireless sensor networks. Therefore, unlike current solutions, the LWB requires no information of the network topology, and inherently supports networks with mobile nodes and multiple data sinks. A LWB prototype implemented in Contiki guarantees bounded end-to-end communication delay and duplicate-free, inorder packet delivery—key QoS requirements in many control and mission-critical applications. Experiments on two testbeds demonstrate that the LWB prototype outperforms state-of-theart data collection and link layer protocols, in terms of reliability and energy efficiency. For instance, we measure an average radio duty cycle of 1.69 % and an overall data yield of 99.97 % in a typical data collection scenario with 85 sensor nodes on Twist. I
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