Stiffness and strength models are derived for simply supported composite sandwich panels comprised of fibre-reinforced face sheets and polymer cores subject to symmetric four point bending and uniformly distributed loading. Optimal trajectories for minimum mass design are calculated using the models and situated on failure mechanism maps. A stiffness constraint is also derived to omit beam designs of excessive compliance. Analytical models were validated through an extensive series of experiments, considering beams comprised of GFRP face sheets with ROHACELL 51-IG and extruded polystyrene (EPS) polymer cores. An alternate loading fixture was used to simulate uniform pressure loads. In general, experiments were able to validate most analytical expressions for a range of experimental conditions. Though the predictions worked well with most beam cases, analytical models were noted to become unreliable for short or slender beams.

For a topological space X, the fundamental group can be topologized as a quotient of the path space with the compact-open topology. For one-dimensional or planar Peano continua, the fundamental group with this topology is a topological group if and only if it is semilocally simply connected. In particular, we demonstrate that the group operation is not continuous in this setting.

This thesis has investigated the application of CFRP and GFRP bars as longitudinal reinforcement for continuously supported concrete beams. Two series of simply and continuously supported CFRP and GFRP reinforced concrete beams were tested in flexure. In addition, a continuously supported steel reinforced concrete beam was tested for comparison purposes. The FRP reinforced concrete continuous beams were reinforced in a way to accomplish three possible reinforcement combinations at the top and bottom layers of such continuous beams. The experimental results revealed that over-reinforcing the bottom layer of either the simply or continuously supported FRP beams is a key factor in controlling the width and propagation of cracks, enhancing the load capacity, and reducing the deflection of such beams. However, continuous concrete beams reinforced with CFRP bars exhibited a remarkable wide crack over the middle support that significantly influenced their behaviour. The ACI 440.1R-06 equations have been validated against experimental results of beams tested. Comparisons between experimental results and those obtained from simplified methods proposed by the ACI 440 Committee show that ACI 440.1R-06 equations can reasonably predict the load capacity and deflection of the simply and continuously supported GFRP reinforced concrete beams tested. However, The potential capabilities of these equations for predicting the load capacity and deflection of continuous CFRP reinforced concrete beams have, however, been adversely affected by the de-bonding of top CFRP bars from concrete. An analytical technique, which presents an iterative procedure based on satisfying force equilibrium and deformation compatibility conditions, has been introduced in this research. This technique developed a computer program to investigate flexural behaviour in particular the flexural strength and deflection of simple and continuously supported FRP reinforced concrete beams. The analytical modelling program has been compared against different prediction methods, namely ACI 440, the bilinear method, mean moment inertia method and Benmokrane¿s method. This comparison revealed the reliability of this programme in producing more enhanced results in predicting the behaviour of the FRP reinforced beams more than the above stated methods.

No description available.

No description available.

When a concentrated load is introduced perpendicular to the flanges of a steel beam, this condition is referred to as Patch loading (Gozzi, 2007). This occurrence is common in many steel structures, for example at supports or during launching of bridges. Because of the usual slenderness of I-beams and other plated structures, these are sometimes reinforced with stiffeners in order to avoid buckling. Modifications, such as adding stiffeners to a beam, are done to make greater plastic deformations possible before buckling can occur; thereby increasing the resistance against failure. Transverse stiffeners are added in areas where the beam is exposed to concentrated loads (Lagerqvist, 1994). The descriptions of calculating patch loading in the Eurocode are presented for cases of double stiffeners, with the load applied in between two stiffeners with same distance to each of them, or when there is one single stiffener that is acting in line with the load. In the Eurocode there are also descriptions on how to calculate on the resistance against patch loading when there are no stiffeners added. However, the Eurocode lacks descriptions for cases when the stiffeners are misaligned. The purpose of this paper is the evaluation of the impact from transverse stiffeners to the resistance of welded I-beams, when the stiffeners are misaligned and where the length of the beam varies. Because of the complexity of such of problems it is almost impossible to find theoretical solutions (Lagerqvist & Johansson, 1996). Therefore, in this study as well as in almost all studies that aim to predict the ultimate resistances of steel beams subjected to patch loading, the results are gained empirically. The tests herein were done by FE-modeling and the results from the physical experiments done in Lagerkvist’s doctoral thesis were used for validation of the model, as conducting experiments ourselves was not economically possible. 6 The study was made in two steps. In the first step FE-models were produced under the same circumstances as the results obtained by Lagerqvist (1994). Those analyses were not part of the aim of the study; the intention for making the initial analyses was to strengthen the reliability of the results. From there, the final analyses were made with the aim in investigating the influence of stiffeners on the resistance, when these are misaligned. In this step, observations were also made with regards to the impact of the bending moment of the beam on its resistance. The initial analyses, which were made for validation of the modeling, had a satisfying correspondence to the physical experiments; hence the final analyses are assumed valid of acceptance. From observations of the results in the final analyses it is noticed that adding stiffeners is a highly preferred way of increasing the resistance for slender beams. For full utilization it is however important to have the stiffeners optimally placed, because a small deviation from this position gives an unwanted decrease in resistance.

No description available.

Apresentamos um estudo das álgebras de incidência que são hereditárias por partes, as quais denominamos Phias, piecewise hereditary incidence algebras. Através da aljava com relações, descrevemos as Phias de tipo Dynkin e introduzimos uma nova família de Phias de tipo Dynkin extendido chamada família ANS, em referência a Assem, Nehring e Skowronski. Nessa descrição, o importante método foi o dos cortes em extensões triviais, os quais inspiraram a elaboração de um programa que concebe exatamente os cortes na extensão trivial dada que resultam em álgebras de incidência. Abordamos as Phias &#922\\&#916 de tipo feixes, estudando o &#922\\&#916-módulo sincero canônico M e a álgebra de extensão por um ponto &#922\\&#916[&#924]. Demonstramos que se &#922Q/I é uma álgebra sincera, quase-inclinada canônica de tipo aljava e tipo de representação infinito, então os &#922Q/I-módulos sinceros são excepcionais. Essa conclusão permite construir uma gama de Phias &#922\\&#916[&#924] de tipo selvagem. Exploramos as Phias simplesmente conexas, provando uma resposta positiva para o problema de Skowronski para &#922\\&#916 uma Phia de tipo H, com grafo de objetos inclinantes &#922_D^b (&#919) conexo: o grupo &#919^1(&#922\\&#916) é trivial se, e somente se, a álgebra &#922\\&#916 é simplesmente conexa. Na área homológica, determinamos um limitante superior da dimensão global forte das Phias; mais ainda, ampliamos esse resultado para as álgebras sinceras provando que dada uma álgebra sincera e hereditária por partes, sua dimensão global forte é menor ou igual a três. / We present a study of incidence algebras that are piecewise hereditary, which we denominate Phias. By means of the quiver with relations, we describe Phias of Dynkin type and introduce a new family of Phias of extended Dynkin type, which we call ANS family, in reference to Assem, Nehring, and Skowronski. In this description, the important method was the one of cuts on trivial extensions, inspiring the writing of a program that shows exactly the cuts on the given trivial extension that result on incidence algebras. We approach sheaves type Phias &#922\\&#916, studying the canonical sincere &#922\\&#916-module M and the one-point extension algebra &#922\\&#916[&#924]. We show that if &#922Q/I is a sincere, quasi-tilted canonical algebra of quiver type and infinite representation type, then sincere &#922Q/I-modules are exceptional. This conclusion allows the construction of a wide range of Phias &#922\\&#916[&#924] wild type. We explore the simply conectedeness of Phias, proving a positive answer of the so called Skowronski problem for &#922\\&#916 a Phia H type, with connected quiver of tilting objects &#922_D^b (&#919): the group &#919^1(&#922\\&#916) is trivial if, and only if, &#922\\&#916 is a simply connected algebra. On homology, we determine an upper bound for the strong global dimension of Phias; furthermore, we extend this result for sincere algebras proving that the strong global dimension of a sincere piecewise hereditary algebra is less or equal to three.

Cette thèse s’inscrit dans le cadre du projet Région Aquitaine - INRIA : ITIPY. Ce projet vise à terme l’extraction automatique d’itinéraires à partir de récits de voyage du XIX ème et du début du XX ème siècle. Notre premier travail fut de caractériser le corpus comme échantillon du français, par une étude contrastive d’une part de données quantitatives et d’autre part de la structure des récits de voyage. Nous nous sommes ensuite consacrée à l’étude du temps, et plus particulièrement à l’analyse automatique de la sémantique des temps verbaux du français. Disposant d’un analyseur syntaxique et sémantique à large échelle du français, basé sur les grammaires catégorielles et la sémantique compositionnelle (λ-DRT), notre tâche a été de prendre en compte les temps des verbes pour reconstituer la temporalité des événements et des états, notions regroupées sous le termes d’éventualité. Cette thèse se concentre sur la construction d’un lexique sémantique traitant des temps verbaux du français. Nous proposons une extension et une adaptation d’un système d’opérateurs compositionnels conçu pour les temps du verbe anglais, aux temps et à l’aspect du verbe français du XIX ème siècle à nos jours. Cette formalisation est de facto opérationnelle, car elle est définie en terme d’opérateurs du λ-calcul dont la composition et la réduction, déjà programmées, calculent automatiquement les représentations sémantiques souhaitées, des formules multisortes de la logique d’ordre supérieur. Le passage de l’énoncé comportant une éventualité seule au discours, dont le maillage référentiel est complexe, est discuté et nous concluons par les perspectives qu’ouvre nos travaux pour l’analyse du discours. / This work has been lead in the frame of the ITIPY project which goal was to automatically extract itineraries from travel novels from the XIX th century and from the beginning of the XX th. Our thesis work is close to the text understanding task in the information retrieval field and we aim at building a representation of meaning of linguistic utterances, leaning on the compositionnality principle. More precisely, the itinerary extraction supposes to temporally represent displacement and localization events or states (that we actually call eventualities) of a traveler as far as we understand it through discourse. Working on an automatic parser for syntax (in categorial grammars) and semantics (in λ-DRT), we focused on the building of an semantic lexicon for tense in French. We actually characterized our corpora as a sample of French language, by the means of a quantitative and qualitative analysis as well as a study of the internal structure of this genre. The main contribution of this work deals with tense and aspect semantic processing of the event expressed by tensed verbs, and with its modelling. In this respect, we propose an adaptation and an extension for French from XIX th century to nowadays of a lexicon originally produced to deal with English verbs. This formalisation is operational, for it is defined in λ-calculus which composition and réduction, already implemented, calculate automatically semantics représentations, high order logic formulas. Transition from a single event uterrance to a whole discourse which contains a complex referential network is discussed and allows us to define the limits of this hereby work.

This thesis aims to map the occurrence of reproduction of own and other people's language in everyday communication and focus on characteristic features of spokenness. After the first part, which will study this issue in theoretical level, proceed to the analysis. Everything will be completed by pondering on the research results and their implications. The material from which the work is based, consists monologues and dialogues of 65 people of different ages, gender and social inclusion. By these criteria the material is also categorized and analyzed in the context of reproduction and of characteristic features of spokenness in all layers of simple communicative style. All the material isn't older than two years and using by a recording equipment is maintained in spoken and subsequently also in written form.