97 research outputs found
MDOCS Poster-2018-02-06, Issam Nassar
No full textFebruary 6, 6pm
Location: Payne Room
Free and open to the public.
In conjunction with the exhibition This Place
Part of the Palestinian Voices series, organized and co-sponsored by the John B. Moore Documentary Studies Collaborative (MDOCS), the Environmental Studies and Sciences Program, International Affairs, Media and Film Studies, Art History, History, Hayat, and the Skidmore College Dean’s Office
Join us for a lecture by Issam Nassar on the history of Palestinian photography. Nassar is a historian of the Modern Middle East and of Photography at Illinois State University. His work focuses on the modern Middle East and the history of photography. He is the co-editor of Jerusalem Quarterly and the author and editor of a number of books, including the editor of I Would Have Smiled: Photographing the Palestinian Refugee Experience (Institute for Palestinian Studies, 2009) with Rashā Salṭī, and The Story of Jerusalem (Olive Branch Press, 2013).
Murat Yildiz, Assistant Professor of History at Skidmore College, will introduce Nassar and moderate a discussion following the talk.
This talk is part of exhibition This Place, on view February 3 through April 22, 2018, as well the Palestinian Voices series. The Palestinian Voices series is organized and co-sponsored by the John B. Moore Documentary Studies Collaborative (MDOCS), the Environmental Studies and Sciences Program, International Affairs, Media and Film Studies, Art History, History, Hayat, and the Skidmore College Dean’s Office.
This event is free and open to the public
Study of impact on helicopter blade
No full textThis article presents a study of damage in structures that are similar to helicopter blade sections, subjected to an impact. These complex composite structures were impacted by a steel ball of 125 g at impact speed ranging from 30 to 130 m/s. This led to properly highlight the kinematics of the impact and to define the sequence of the damage’s mechanisms. An explicit FE model is also presented. The damage modelling of the roving is performed through a scale change. It allows a good representation of observed experimental behaviour. As the mesh density is low, it can be used for the modelling of a real structure
Study and modelling of impacts on hybrid epoxy foam - aramid ply composite structures
No full textL'objectif de ce travail est d'étudier le comportement à l'impact d'une nouvelle structure hybride, constituée d'une mousse époxy et de plis d'aramide. L'étude est composée de deux axes principaux avec une partie expérimentale et une partie d'étude numérique. Dans la partie expérimentale, plusieurs configurations de structures sont fabriquées et testées pour étudier l'influence du nombre et de l'emplacement des plis d'aramide, ainsi que de la densité de la mousse époxy sur la résistance à l'impact. Une série de tests à basse et haute vitesse a été réalisée. La capacité de protection des structures hybrides est évaluée en mesurant l'indentation permanente et l'indentation résiduelle après l'impact sur un matériau de référence. Un modèle numérique est développé pour simuler le comportement à l'impact des structures hybrides. Les plis d'aramide sont modélisés avec une stratégie de modélisation 3D semi-continue, développée au cœur de ce travail. La mousse époxy est modélisée avec une loi de matériau intégrée pour les mousses endommageables. Le modèle numérique est ensuite implémenté dans le logiciel d'éléments finis Radioss. Une caractérisation mécanique est effectuée sur les matériaux étudiés, afin d'examiner leur comportement et de définir les paramètres et lois nécessaires, en amont de la modélisation. Le modèle numérique est alors capable de prédire les mécanismes d'endommagement des structures hybrides, tels que la rupture des fibres, la fissuration de la matrice pour les plis d'aramide, et l'écrasement pour la mousse époxy. Le modèle numérique pourra ainsi servir d'outil de développement et d'optimisation dans les travaux ultérieurs.This work aims to study the impact behavior of a new hybrid epoxy foam/ aramid plies structure. The study includes two main parts: an experimental and a numerical one. In the experimental part, several structure configurations are fabricated and tested to assess the influence of the number and location of the aramid plies and the epoxy foam density on their resistance to impact. A series of low-velocity and high-velocity tests are achieved. The protection capacity of the hybrid structures is evaluated by assessing the permanent indentation and the indentation left post impact on reference material. A numerical model is developed to simulate the impact behavior of the hybrid structures. The aramid plies are modeled with a semi-continuous modeling strategy developed at the core of this work. The epoxy foam is modeled using a standard material law for crushable foams; the numerical model is implemented in the finite element software Radioss. Mechanical characterization is performed on the studied materials to examine their behavior and to define needed parameters for the constitutive models. The numerical model can predict the mechanisms of failure in the hybrid structures, characterized by fiber breakage and matrix crack for the aramid and crushing for the epoxy foam. The numerical model will serve as an optimization tool in future work
Modelling of impacts on unidirectionnal and hybrid composite laminates
No full textLes structures aéronautiques sont aujourd’hui largement réalisées à partir de matériaux composites, permettant ainsi d’en diminuer la masse. L’impact sur structure composite est une des sources de dommage la plus courante et la plus pénalisante. L’objectif de cette thèse est de développer un modèle prédictif d’impact sur stratifiés unidirectionnels de faible épaisseur afin, dans un premier temps, de mieux comprendre les mécanismes d’endommagement mis en jeu et, dans un deuxième temps, de pouvoir proposer des pistes d’amélioration de la tenue de ces structures. La première étape de ces travaux a consisté à développer un modèle éléments finis explicite de stratifiés composite unidirectionnel, en s’appuyant sur les travaux d’impact sur pale d’hélicoptère réalisés par F. Pascal. Ainsi, un nouvel élément capable de représenter le comportement à l’impact des plis unidirectionnels a été formulé. Le comportement des paquets de fibres est représenté par des éléments barres stabilisés grâce à des éléments 2D spécifiques. La dégradation de ces éléments est pilotée par des lois d’endommagement déduites d’observations expérimentales. La stratégie de modélisation proposée a été identifiée sur la base d’essais expérimentaux pour deux matériaux : T700/M21 et HTA7/913. Les résultats donnés par le modèle ont ensuite été validés par une comparaison avec des essais d’impact à basse vitesse. Enfin, dans le but d’optimiser la tenue des stratifiés, des impacts à basse et moyenne vitesse sur des stratifiés hybrides unidirectionnels/tissus composites ont été étudiés expérimentalement et numériquement grâce à la stratégie de modélisation proposée.Today, composite materials are largely used in the manufacturing of aeronautical structures, in order to lighten their weight. Impact on composite structures is one of the most detrimental loading. The present study aims to develop a predictive modelling of impacts on thin unidirectional laminates in order to, firstly, better understand the damage mechanisms involved, and, secondly, be able to provide guidance for a strength improvement of these structures. First, an explicit finite element modelling of unidirectional laminates is developed based on the work of F Pascal dealing with impact modeling on helicopter blades. Thus, a new element that can represent the impact response of unidirectional plies is formulated. The behavior of the bundle of fibers is modeled with rod elements stabilized with specific 2D elements. The degradation is managed using damage based on experimental observations. The parameters of the proposed modelling strategy are identified on the basis of experimental tests carried out on T700/M21 and HTA7/913 composites. The results provided by the modeling are then validated by a comparison with experimental low velocity impact results. Finally, in order to improve the laminate strength, low velocity and medium velocity impacts on hybrid unidirectional/woven composite laminates are studied experimentally and with the developed modelling strategy
Steel Slag Aggregate Characteristics Evaluation as Railway Ballast
No full textThe use of recycled materials is a new tendency in the field of railway engineering. Steel slag aggregates (SSA) are one of the recycled materials derived from the steel industry. The application of SSA in ballasted railway tracks requires mechanical examination. In the present paper, the shear behavior of the ballast layer constructed by SSA and basalt aggregates was considered to assess the use of SSA as a substitution for basalt. In this regard, a series of large-direct shear tests were performed on basalt and SSA under various normal stresses. Based on the results, basalt aggregates have higher shear resistance than SSA for all normal stress. However, steel slag has sufficient shear strength as well as particle abrasion resistance. Overall, it was proven that the SSA has suitable stability against shear forces that could be applied on railway ballast.Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Railway Engineerin
Problem Solving Through Emerging Technologies
No full textAbstract: This article offers a discussion of the overall role of problem management process among emerging technologies when companies attempt to solve problems that affect their revenue and profit streams. The findings of this study have shown that different technologies that have emerged over the past decade have helped companies solve problems that might be significantly harder to solve if the firm simply depended upon humans. Technologies such as Artificial Intelligence (AI) and Predictive Analytics (PA) have been especially helpful. AI can support companies become proactive to solve problems before they have become financially or technically problematic. The employment of PA can support companies predict patterns for potential technical issues and/or even predict customers’ future performance in terms of what they will buy, based on what they have already bought. The advantage of such analytics is not just for problem-solving but also to delight customers and provide better services. For the future, companies shall improve in the competency of matching up the current problem with the technology best designed to solve such a problem.
Keywords: Problem Solving Process, Information Technology Service Management, Internet of Things (IoT), Predictive Analytics, Artificial Intelligence, 4th Industrial Revolution, Public Onchain Database, Metadata, Augmented Reality.
Title: Problem Solving Through Emerging Technologies
Author: Ahmad Issam Alzahed
International Journal of Computer Science and Information Technology Research
ISSN 2348-1196 (print), ISSN 2348-120X (online)
Vol. 10, Issue 3, July 2022 - September 2022
Page No: 45-49
Research Publish Journals
Website: www.researchpublish.com
Published Date: 05-September-2022
DOI: https://doi.org/10.5281/zenodo.7050274
Paper Download Link (Source)
https://www.researchpublish.com/papers/problem-solving-through-emerging-technologiesInternational Journal of Computer Science and Information Technology Research, ISSN 2348-1196 (print), ISSN 2348-120X (online), Research Publish Journals, Website: www.researchpublish.co
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