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Définition des indicateurs clés de performance et évaluation multicritère de filières durables de recyclage des polymères renforcés de fibres de carbone issus de l’industrie aéronautique / Definition of key sustainability performance indicators and multicriteria evaluation of recycling sector for carbon fiber reinforced polymers from the aerospace industryPillain, Baptiste 30 June 2017 (has links)
La consommation globale de plastique renforcé de fibres de carbone (PRFC) est en constante augmentation, ce qui induit la nécessité de créer un secteur de recyclage capable de traiter l’ensemble des fibres de carbone actuellement consommées et qui représente la quantité de déchets à traiter en devenir. Cette thèse porte sur le développement et l'application d’une méthodologie d’évaluation multicritère du développement durable pour la création d’une filière de recyclage des plastiques renforcés de fibres de carbone (PRFC) issus du secteur aéronautique, mais aussi des autres secteurs consommateurs de fibres de carbone tels que l’automobile et l’éolien. Cette méthodologie a pour but d’identifier les indicateurs les plus pertinents ainsi que les méthodes qui leurs sont associés, c'est-à-dire qu’elle vise à la création et l’adaptation d’indicateurs clé de performance du développement durable pour caractériser au mieux les impacts environnementaux et sociaux-économique de cette filière de recyclage. Le résultat final de ce travail est la création d’une méthodologie d’évaluation du développement durable dédiée à la filière de recyclage des fibres de carbone par la considération des différents aspects de celui-ci. Cette méthodologie, aidant à l’identification et la définition des indicateurs clé de performances du développement durable peut être aussi appliquée à d’autres secteurs souhaitant s’implanter en suivant les principes de ce développement. / The global consumption of carbon-fiber reinforced plastic (CFRP) is constantly growing since the last decade, leading to the need to create a recycling sector able to manage the amount of carbon fibers currently consumed and representing the amount of waste to be treated in the future. This thesis focus on the creation of a methodology for evaluating the sustainability potential for the implementation of a carbon fiber reinforced plastics recycling (CFRP) sector. CFRP coming from the aeronautics sector as well as other sectors such as the automobile and wind-energy industries. This methodology aims at identifying the most relevant indicators and associated methods, but also aims at the creation and adaptation of indicators to best assess the environmental and socioeconomic impacts of this recycling sector. The final result of this work, is the creation of a sustainability assessment methodology dedicated to the carbon fiber recycling sector, considering the different sustainability pillars. However this methodology also define more widely a tool that helps to identify sustainability performance indicators and that can be applied to other sectors if necessary.
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Fatigue Damage Characterization Of Carbon/Epoxy Laminates Under Spectrum LoadingSudha, J 01 1900 (has links) (PDF)
Fibre Reinforced Polymer Composites are extensively used in aircraft structures because of its high specific stiffness, high specific strength and tailorability. Though Fibre Reinforced Polymers offer many advantages, they are not free from problems. The damage of different nature, e.g., service mechanical damages, fatigue damage or environmental damage can be observed during operating conditions. Among all the damages, manufacturing or service induced, delamination related damage is the most important failure mechanisms of aircraft-composite structures and can be detrimental for safety. Delamination growth under fatigue loading may take place due to local buckling, growth from free edges and notches such as holes, growth from ply-drops and impact damaged composites containing considerable delamination. Delamination growth can also occur due to interlaminar stresses, which can arise in complex structures due to unanticipated loading.
The complex nature of composite failure, involving different failure modes and their interactions, makes it necessary to characterize/identify the relevant parameters for fatigue damage resistance, accumulation and life prediction. An effort has been made in this thesis to understand the fatigue behavior of carbon fibre reinforced epoxy laminates under aircraft wing service loading conditions. The study was made on laminates with different lay-up sequences (quasi-isotropic and fibre dominated) and different geometries (plain specimen, specimen with a hole and ply-drop specimen).
The fatigue behaviour of the composite was analyzed by following methods:
. Ultrasonic C-Scan was used to characterize the delamination growth.
. Dynamic Mechanical Analysis (DMA) was done to study the interfacial degradation due to fatigue loading. In this analysis, the interfacial strength indicator and interfacial damping were calculated. The DMA also provides the storage modulus degradation under fatigue loading.
. Scanning electron microscope examination was carried out to understand the fatigue damage mechanisms.
. A semi-empirical phenomenological model was also used to estimate the residual fatigue life.
This research work reveals that the Carbon Fibre Reinforced Polymer laminates are in the safe limit under service loading conditions, except the specimen with a hole. The specimen with a hole showed delaminations around the hole due to stress concentration and higher interlaminar stresses at the hole edges and this delamination is found to be associated with fibre breakage and fibre pullout. The quasi-isotropic laminate is found to show poorer fatigue behaviour when compared to fibre dominated laminate and ply-drop also shows poor performance due to high stress concentration in the ply-drop region.
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Zesílení kruhových sloupů při příčném cyklickém namáhání / Strengthening of circular column subjected to lateral cyclic loadingMansour, Mohamad January 2019 (has links)
Předložená disertační práce se zabývá zesílením kruhových železobetonových sloupů pomocí vlákny vyztužených polymerů (tzv. FRP – fibre reinforced polymer) namáhaných laterálním cyklickým zatížením. Tato výzkumná studie se zaměřuje na zkoumání využití FRP tkaniny pro dodatečné zesílení, zlepšení chování kruhových železobetonových sloupů a vytvoření návrhového algoritmu pro zesílení kruhového sloupu pomocí kompozitních FRP materiálů. Návrhový algoritmus byl odvozen na základě analytické studie, numerických simulací a výsledků experimentální činnosti. Na základě těchto výsledků byl navržen postup pro návrh zesílení sloupů ovinutím, který předpovídá chování železobetonových sloupů vystavených laterálním cyklickým zatížením. Při experimentální práci byly zkušební vzorky zatíženy současně axiální sílou a příčným cyklickým zatížením. Toto bylo provedeno dvěma různými způsoby. První způsob zatěžování byl proveden konstantní velikostí laterální síly po daný počet cyklů (1 milion) se sledováním změny deformace. A druhý způsob provedení spočíval v zatížení konstantní deformací se sledováním úbytku síly během zatěžovací zkoušky. Dizertační práce rovněž předkládá přehled současného stavu poznání zesílení železobetonových kruhových sloupů ovinutím FRP tkaninou vystavených působení seismického zatížení. Dále uvádí přehled návrhových metodik a normová ustanovení Eurokódu a ACI. Experimentální program byl proveden za účelem ověření chování ovinutých kruhových sloupů při působení laterálního cyklického zatížení. Závěr práce sumarizuje poznatky o chování sloupů zesílených ovinutím FRP tkaninou při působení laterálního cyklického zatížení a představuje empirický model pro návrh zesílení ovinutím při vysokém a nízkém cyklickém zatížení.
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Skalenübergreifende Modellierung und Simulation des mechanischen Verhaltens von textilverstärktem Polypropylen unter Nutzung der XFEMKästner, Markus 04 December 2009 (has links)
Die Arbeit beschreibt die skalenübergreifende Modellierung und Simulation des Werkstoffverhaltens von Faser-Kunststoff-Verbunden mit textiler Verstärkungsstruktur, die ausgehend von den konstitutiven Eigenschaften der Verbundbestandteile (Mikroskala) und ihrer geometrischen Anordnung im Verbund (Mesoskala) die rechnerische Vorhersage des effektiven Materialverhaltens des Verbundes (Makroskala) ermöglicht.
Neben Schädigungsprozessen beeinflusst insbesondere das dehnratenabhängige Materialverhalten der polymeren Matrix das mechanische Verhalten des Verbundes. Dieser Einfluss wird anhand verschiedener Glasfaser-Polypropylen-Verbunde numerisch untersucht. Ein viskoplastisches Materialmodell bildet dabei das nichtlineare Materialverhalten von Polypropylen ab. Die Modellierung der textilen Verstärkungsstruktur erfolgt durch Anwendung der erweiterten Finiten-Elemente-Methode (XFEM). Anhand des Vergleichs von rechnerisch und experimentell gewonnenen Ergebnissen erfolgt schließlich die Verifikation der vorgeschlagenen Modellierungsstrategie. / This contribution covers the trans-scale modelling and simulation of the mechanical behaviour of textile-reinforced polymers. Starting from the material properties of the individual constituents (micro-scale) and their geometrical arrangement (meso-scale), the effective material behaviour of the composite (macro-scale) is numerically predicted.
In addition to damage processes, the inelastic deformation behaviour of the composite is influenced by the strain-rate dependent material behaviour of the polymeric matrix. This influence is numerically investigated for different glass-fibre-polypropylene composites. A viscoplastic material model accounts for the nonlinear mechanical behaviour of polypropylene. The complex textile reinforcement is modelled by the eXtended finite element method (XFEM). A comparison of computed and experimental results allows for the verification of the proposed modelling strategy.
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Feasibility Analysis of a Fiber Reinforced Polymer BridgeMurphy, Neil January 2013 (has links)
When implementing a bridge design proposal, it is common that several alternatives be considered, each with a different material of construction. Traditional building materials used for the construction of bridges have mainly been concrete, steel, timber or aluminium. With all these materials options, maintenance and replacement costs throughout the lifespan of a bridge make up for a large proportion of their total life cycle costs. Fiber Reinforced Polymer (FRP) provides a new viable construction material, which can be implemented in bridge construction. This plastic based material has favourable material properties such a very high strength to weight ratio, high corrosion resistance and durability, as well as very low maintenance costs over its lifetime. In the feasibility analysis, a case study of an existing FRP deck bridge was taken and examined in three aspects: structural, economic and environmental. The bridge was also redesigned with a concrete deck solution, to provide a comparison to a conventional construction material. The results were found, in general to be favourable towards the FRP solution. From the structural analysis savings on deflection, support reactions and superstructure stresses were outputted. Economically, the composite material was found to have a substantial higher initial cost but much lower periodic maintenance costs than the concrete option. Finally the FRP bridge option displayed a lower construction time for the superstructure, at one third of that of concrete and an overall lower environmental impact, based on material production and the overall bridge construction process.
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Widening of The Nockeby Bridge : Methods for strengthening the torsional resistanceAndersson, Jenny January 2016 (has links)
i Abstract The Nockeby Bridge, in the western part of Stockholm, is a prestressed concrete bridge with an openable swing span of steel. The bridge was built during 1970 and should now be widened with 0.5 meters on each side. The concrete bridge deck is supported by two main-beams and cross-beams are located at the position of all supports. Previous studies of the bridge show that the torsional resistance is too low and the bridge needs strengthening while widened. The aim of this master thesis was to study and compare different strengthening methods for The Nockeby Bridge. Eight different bridges in Sweden and China were reviewed to find possible strengthening methods for The Nockeby Bridge. External prestressing tendons and additional cross-beams between the two main-beams were seen to have good influence on the resistance. The effect from strengthening with carbon-fiber reinforced polymer was questioned during small loads and was not seen as a suitable strengthening method for The Nockeby Bridge. Four different FE-models were generated to be able to compare two strengthening methods. The compared strengthening methods were a method with additional cross-beams between the main-beams and a method with external prestressing tendons. All FE-models were built up by solid- and truss elements where the concrete was modelled with solid elements and the prestressed reinforcement was modelled with truss elements. Only a few load-cases were included to limit the scope of the study. The included load-cases were deadweight, prestressing forces and vehicle load from standard vehicle F, G, H and I. Two influence lines were created to be able to place the vehicle loads in an unfavorable way. From the FE-models, shear stresses were extracted along two lines, one on each side of the main-beam. The torsional part of the shear stresses was calculated from these two results and compared with the torsional resistance of the bridge. While calculating the torsional resistance, the normal force in the cross-section from prestress was extracted with the function “free body cut”. The results showed that none of the tested strengthening methods were enough to strengthen The Nockeby Bridge. However, the method with additional cross-beams was seen as a better method than external prestressing tendons. A combination of the two methods might be suitable but was not tested. Adding four cross-beams in each span might also increase the resistance enough, but this was neither tested. It was also seen that a reduction of the torsional stiffness had a large influence on the result. Such a reduction is allowed in some cases and should be utilized if possible. Furthermore, it was seen that solid-models were extremely time consuming and there is not a good alternative to design a bridge with only a solid model. / Nockebybron i västra Stockholm är en förspänd betongbro med ett öppningsbart svängspann av stål. Bron byggdes 1970 och ska nu breddas med 0.5 meter på varje sida. Betongplattan stöds upp av två huvudbalkar och tvärbalkar är placerade vid samtliga stöd. Tidigare studier av bron visar att brons vridstyvhet är låg och bron behöver förstärkas i samband med breddningen. Syftet med detta examensarbete är att undersöka och jämföra olika förstärkningsmetoder för Nockebybron. Åtta olika broar i Sverige och Kina undersöktes för att hitta möjliga förstärkningsåtgärder för Nockebybron. Extern spännarmering och extra tvärbalkar mellan de två huvudbalkarna hade en bra inverkan på kapaciteten. Kapacitetsökningen fån förstärkning med kolfiberförstärkt plast är ifrågasatt vid låga laster och uppfattas inte som en bra metod för att förstärka Nockebybron. Fyra olika FE-modeller skapades för att jämföra två förstärkningsmetoder. Förstärkningsmetoderna som jämfördes var metoden med extra tvärbalkar mellan huvudbalkarna samt en metod extern spännarmering. Alla FE-modeller byggdes upp med solid- och stångelement där betongen modellerades med solidelement och den förspända armeringen modellerades med stångelement. Enbart ett fåtal lastfall inkluderades i studien för att minska studiens omfattning. De inkluderade lastfallen var egenvikt, förspänningskrafter samt trafiklast från typfordon F, G, H och I. Två influenslinjer skapades för att placera trafiklasten på ett ogynnsamt sätt. Från FE-modellerna extraherades skjuvspänningar från bägge sidor av en av huduvbalkarna. Från dessa skjuvspänningar beräknades vrid-delen av skjuvspänningarna som jämfördes med brons vridkapacitet. När vridkapaciteten beräknades togs tryckkraften från tvärsnittet fram genom funktionen ”free body cut”. Resultatet visade att ingen av de testade förstärkningsmetoderna var tillräckliga för att förstärka Nockebybron. Hur som helst, metoden med extra tvärbalkar ansågs som en bättre metod än extern spännarmering. En kombination av de bägge förstärkningsmetoderna kan vara lämplig men detta testades inte. Att lägga in fyra tvärbalkar i varje spann kan också leda till en tillräcklig ökning av kapaciteten, men detta fall testades inte heller. En reduktion av vridstyvheten sågs ha en stor påverkan på resultatet. En sådan reduktion är tillåten i vissa fall och borde utnyttjas om möjligt. Vidare upptäcktes att en solidmodell är väldigt tidskrävande varför det inte är lämpligt att dimensionera en bro enbart med hjälp av en solidmodell.
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EXPERIMENTAL INVESTIGATION OF REPAIR TECHNIQUES FOR DETERIORATED END REGIONS OF PRESTRESSED CONCRETE BRIDGE GIRDERSWilliam Rich (10713612) 06 May 2021 (has links)
<div>
<p>Due to harsh environmental conditions, the deterioration of
prestressed concrete bridge girders is a commonly observed phenomenon in
Indiana and much of the Midwest. Concordantly, one widely observed damage
scenario is deteriorated end regions of prestressed concrete girders. Damaged
or failed expansion joints expose prestressed concrete girder end regions to
chloride-laden water, resulting in a corrosive environment in which
reinforcement section loss and concrete spalling can occur. For bridges
experiencing this type of deterioration, action is needed to ensure the
structure remains safe and serviceable. As
such, an experimental program was developed to investigate the effectiveness of
three repair techniques in restoring the structural behavior of prestressed
concrete bridge girders with end region deterioration. The three examined
repair techniques are (i) an externally bonded fiber reinforced polymer (FRP)
system, (ii) a near-surface-mounted (NSM) FRP system, and (iii) a concrete
supplemental diaphragm. Additionally, installation procedures for the three end
region repair techniques were developed. Results, conclusions, and
recommendations from the experimental program are presented to help advise best
practices for implementing end region repair techniques in the field. </p>
</div>
<br>
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Incorporation of Bio Based Flax Fiber Reinforced Polymer Skins for Packaging EnhancementsSukhyani, Sufia 12 1900 (has links)
Indiana University-Purdue University Indianapolis (IUPUI) / This thesis provides an approach to incorporate natural composites like Flax Fiber using a resin with 30% bio-content to enhance the packaging boxes made of corrugated cardboard. The objective of introducing natural composite skins is to reduce/eliminate the compressive loading subjected to the boxes while stacking in warehouses.
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Design and Characterization of Composite and Metal Adhesive JointsKaiser, Isaiah 08 August 2023 (has links)
No description available.
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[en] ANALYSIS OF THE HYGRO-THERMO-MECHANICAL BEHAVIOR OF PULTRUDED GLASS-FIBER REINFORCED POLYMER COMPOSITES / [pt] ANÁLISE DO COMPORTAMENTO HIGRO-TERMO-MECÂNICO DE MATERIAIS COMPÓSITOS PULTRUDADOS POLIMÉRICOS REFORÇADOS COM FIBRA DE VIDROPRISCILLA SHIMBA CARNEIRO VIEIRA 04 July 2023 (has links)
[pt] Materiais compósitos pultrudados poliméricos reforçados com fibra de
vidro (PRFV) são aplicados em diversos setores da indústria por apresentarem boas
resistências mecânicas, baixo peso específico e alta resistência à corrosão. A
exposição a ambientes agressivos tais como imersão em água, condicionamento sob
alta umidade relativa, temperatura baixa e elevada, ciclos térmicos e úmidos, bem
como a combinação desses efeitos, tornou-se cada vez mais objeto de estudo para
esses tipos de materiais. A compreensão dos efeitos das condições ambientais no
comportamento do material é essencial para avaliar seu desempenho e, desta forma,
garantir a segurança necessária ao projeto estrutural. Com o objetivo de
compreender melhor a influência de diferentes condições ambientais nas
propriedades do material compósito PRFV, foram estudados os efeitos da
temperatura e umidade, além da ação combinada dessas duas condições, nas suas
propriedades físicas, químicas, térmicas e mecânicas. Neste estudo, foram levados
em conta aspectos importantes que influenciam o comportamento do material,
como a resina utilizada, o grau de cura, e características químicas e físicas do
material. Os ensaios experimentais foram conduzidos em quatro condições
ambientais: (i) exposição a temperaturas moderadas/elevadas (70 graus C à 330 graus C), (ii)
imersão em água deionizada (25 graus C, 55 graus C e 70 graus C), (iii) exposição à névoa salina
em câmaras de envelhecimento higrotérmico (35 graus C, 55 graus C e 70 graus C), e (iv) exposição
a ambiente externo real. Além disso, foram aplicados modelos teóricos para
avaliação dos resultados. Foi observado que a temperatura, o tempo de
condicionamento e a umidade são fatores preponderantes no comportamento do
material. Adicionalmente, uma questão importante para o estudo de pultrudados
reside na compreensão das propriedades interlaminares do material. Nesse
contexto, a fratura interlaminar, associada às fissuras no plano longitudinal entre as
camadas do material, é uma das principais causas de falha em compósitos
pultrudados. Consequentemente, a análise da fratura em modo II, que avalia o
mecanismo da propagação da fissura no plano interlaminar, vem ganhando espaço
no estudo de materiais compósitos. A análise de fratura em modo II não é trivial ou
normatizada para compósitos pultrudados PRFV, de forma que poucos dados e
conclusões efetivas foram obtidos até o momento a esse respeito. Com o objetivo
de suprir essa lacuna, realizou-se uma extensa investigação experimental,
culminando na proposição de uma nova metodologia para avaliação da fratura em
modo II em materiais compósitos poliméricos pultrudados reforçados com fibra de
vidro (PRFV). / [en] Pultruded glass-fiber reinforced polymer (GFRP) composites are applied in
various industrial sectors due to their good mechanical strength, low specific
weight, and high resistance to corrosion. Exposure to aggressive environments has
become an increasingly studied topic for these materials, such as immersion in
water, conditioning under high relative humidity, low and high temperatures,
thermal and humid cycles, as well as the combination of these effects.
Understanding the effects of environment condition on material behavior is
essential to evaluate its performance and ensure the necessary safety for structural
design. In order to better understand the influence of environmental conditions on
the properties of GFRPs, the effects of temperature and humidity, as well as the
combined action of these two effects, on their physical, chemical, thermal, and
mechanical properties were studied. Important aspects that influence the material s
behavior were considered, such as the resin used, the degree of curing, and the
chemical and physical characteristics of the material. Experimental tests were
conducted under four environmental conditions: (i) exposure to moderate/high
temperatures (70 degrees C to 330 degrees C), (ii) immersion in deionized water (25 degrees C, 55 degrees C,
and 70 degrees C), (iii) exposure to salt spray in hygrothermal aging chambers (35 degrees C, 55
degrees C, and 70 degrees C), and (iv) exposure to real outdoor environment. In addition,
theoretical models were applied to evaluate the results. It was observed that
temperature, conditioning time, and moisture are predominant factors in material
behavior. Additionally, a important issue for the study of pultruded composites lies
in understanding the interlaminar properties of the material. In this context,
interlaminar fracture, associated with longitudinal cracks between the layers of the
material, is one of the main causes of failure in pultruded composites.
Consequently, mode II fracture analysis, which evaluates the mechanism of crack
propagation in the interlaminar plane, has been gaining ground in the study of
composite materials. Mode II fracture analysis is not trivial or standardized for
pultruded GFRP composites, so few data and effective conclusions have been
obtained in this regard so far. In order to fill this gap, an extensive experimental
investigation was carried out, culminating in the proposal of a new methodology
for evaluating mode II fracture in pultruded GFRPs.
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