ABSTRACT An evaluation of glass reinforced plastic pipe stub-flange behaviour during hydrostatic pressure testing is presented. Similar flanges made according to different manufacturing methods were analysed. Linear static analysis using MSC Patran / Nastran was performed to predict the critically loaded regions subjected to high stress concentrations. These regions were used for experimental strain gauge locations. Hydrostatic testing designed according to BS 5480 and ASTM F 37 was performed on assembled flange joints to initiate both leakage and ultimate material failure. Experimental strain results were compared to finite element numerical results at the selected locations. Fibre dominated failure characterised by cracks extending through the stub and matrix dominated failure characterised by interlaminar debonding were noticed. The need for further work analyzing GRP flanges subject to mechanical load and taking into account induced residual thermal stress effects is suggested.

During a risk assessment undertaken in a factory dealing with fiber reinforced plastic products in the northwestern part of Peninsular Malaysia, styrene was identified as the most potential hazard in the factory. It was therefore chosen to focus the rest of the risk assessment on this chemical. The purpose of this risk assessment was to find out which negative health effects styrene could have on the factory workers, especially on the laminators who are dealing daily with styrene at a close range during lamination through hand lay-up. This was investigated theoretically through a literature research and practically through measurements of styrene in the air in the factory. The styrene doses were measured on two occasions at several distances away from the potential sources. These measurements were high compared with dose-response relationships found in the literature and various national occupational exposure limit values with regards to styrene. The calculated risk quotient (RQ) was also greater than one and it is therefore likely that styrene has negative health effects on the workers in the factory. The various negative health effects identified in the literature were then included in a risk matrix were they were ranked according to the probability that they would have a negative effect on the factory workers. Hearing- and colourvision effects were ranked as very likely, effects on the central nervous system and the respiratory system as well as livertoxicity were classified as likely and genotoxicity was ranked as a possible negative health effect. In the future it would be interesting to talk to the current laminators and do health check-ups to see if they are suffering from any of the suggested negative health effects. It would also be interesting to follow them on a longterm basis to see if their health is changing and if this can be linked to the styrene handling in the factory. / Vid en riskbedömning i en fabrik i nordvästra Malaysia identifierades styren som den största hälsofaran för fabriksarbetarna, framförallt laminerarna eftersom de ofta hanterar styren på nära håll. Det valdes därför att fokusera den resterande riskbedömningen just på styren och dess möjliga negativa hälsoeffekter. Syftet med studien var att ta reda på om styren kan ha en negativ effekt på fabriksarbetarnas hälsa. Detta undersöktes teoretiskt genom en litteraturstudie och praktiskt genom mätningar av styrenhalten i fabriken. Vid två tillfällen mättes styrenhalten i fabriken. De uppmätta halterna jämfördes sedan med de dos-responssamband som funnits vid litteraturstudien, samt med olika nationella hygieniska gränsvärden för styren. De uppmätta värdena visade sig vara höga jämfört med de funna i litteraturen. Det bidrog tillsammans med den beräknade riskkvoten som visade sig vara större än ett, till slutsatsen att styren har en negativ effekt på fabriksarbetarnas hälsa. De möjliga negativa hälsoeffekter som identifierats i litteraturen rangordnas med hjälp av en riskmatris enligt sannolikheten att de skulle utgjöra en risk för arbetarna i fabriken. Effekter på hörseln och färgseendet ansågs vara mycket sannolikt, effekter på centrala nervsystemet (CNS) och levern samt irritation av andningssystemet ansågs sannolika och att styren skulle vara genotoxiskt ansågs möjligt. Övriga hälsoeffekter ansågs osannolika eller mycket osannolika. I framtida studier skulle det vara intressant att diskutera med de nuvarande laminerarna och undersöka dem medicinskt för att se om de har påverkats utav några av de förväntade hälsoeffekterna. Det vore också intressant att följa dessa arbetare under en längre tid för att se om deras hälsa ändras på något sätt som skulle kunna kopplas till styrenhanteringen i fabriken.

Αντικείμενο της παρούσας Διατριβής Διπλώματος Ειδίκευσης είναι η κατά βάση πειραματική διερεύνηση της αποτελεσματικότητας περίσφιγξης ορθογωνικών υποστυλωμάτων με μεγάλο λόγο πλευρών, ενισχυμένων με μανδύες ινοπλισμένων πολυμερών και σύνθετων υλικών ανόργανης μήτρας. Το πειραματικό πρόγραμμα διεξήχθη στο Εργαστήριο Μηχανικής και Τεχνολογίας Υλικών του Τμήματος Πολιτικών Μηχανικών του Πανεπιστημίου Πατρών. Το πρόγραμμα αυτό, περιελάμβανε δύο σειρές δοκιμίων. Η πρώτη περιελάμβανε έξι δοκίμια και η δεύτερη δέκα. Η κατηγοριοποίηση σε σειρές έγινε με βάση το λόγο πλευρών των δοκιμίων. Έτσι, την πρώτη σειρά αποτέλεσαν δοκίμια με λόγο πλευρών (3:1), ενώ τη δεύτερη δοκίμια με λόγο πλευρών (4:1). Ένα δοκίμιο από κάθε σειρά δοκιμάσθηκε χωρίς ενίσχυση και αποτέλεσε μέτρο σύγκρισης για όλα τα υπόλοιπα. Τρία δοκίμια από κάθε σειρά ενισχύθηκαν με τρείς στρώσεις FRP και με θυσάνους. Ακόμα, ένα δοκίμιο από κάθε σειρά ενισχύθηκε με δύο στρώσεις FRP, χωρίς χρήση θυσάνου. Επίσης, δύο υποστυλώματα από τη δεύτερη σειρά ενισχύθηκαν με δύο στρώσεις FRP, θυσάνους και δύο επιπρόσθετες στρώσεις FRP τύπου U, στις δύο μικρές πλευρές. Τέλος, ένα δοκίμιο από κάθε σειρά ενισχύθηκε με τέσσερις στρώσεις TRΜ, ενώ άλλο ένα με τέσσερις στρώσεις TRΜ και με θυσάνους. / The subject of this thesis is the experimental investigation of the effectiveness of confining rectangular columns with large aspect ratio, reinforced with fiber reinforced polymers and with tensile reinforced mortars. The experimental program was conducted at the Laboratory of Engineering and Technology of Materials in Civil Engineering, University of Patras. This program is consisted of two sets of samples. The first included six small scale columns and the second ten. The categorization in series was based on the aspect ratio of the specimens. So specimens with aspect ratio (3: 1) were included in the first series, while the second included specimens with aspect ratio (4: 1). One specimen from each series was tested without any reinforcement and became the comparison for all the rest. Three specimens from each series were reinforced with three layers of FRP and anchors. Still, a sample from each series was reinforced with two layers of FRP, without use of anchors. Also, two columns of the second series of amplified with two layers FRP, anchors and two additional layers of FRP type U, in the two smaller sides. Finally, a sample from each series was reinforced with four layers TRM, while another one to four layers TRM and anchors.

E-glass has been widely used as a reinforcing material for years, especially as a plastic reinforcer in the production of GRP (Glass Reinforced Plastic). Failure of GRP materials under stress came in to the picture quite recently. Since then studies have been conducted in an attempt to understand the causes and the underlying behaviour. / Except for the last section of the research (analysis using a kinetic approach) where glass fibre was cut out to weigh approximately 1.0g, standard sized specimens were soaked in the required acid solutions of desired concentrations for varying temperatures and time frames. Wherever tensile strength retention was measured, LLOYD instrument was employed. Leaching of the cations were analysed using Inductively Coupled Plasma – Optical Emission Spectroscopy (ICP-OES and also know and ICP-AES). / The scope of this project can be divided in to four sections; first section involved investigating the effects of malonic acid. The study of malonic acid was narrowed to investigating the trend in strength retention. A rapid strength loss was observed initially followed by a much steady decline in the strength. However the continuation of the loss of strength was unmistakable throughout the time period of exposure. Furthermore, temperature can be observed as a facilitating factor in this degradation reaction. / Secondly the corrosive effect of glyoxylic acid on E-glass fibre was studied. This was explored at two different temperatures for two specific time frames using various concentrations of the acid of interest. The influence of this acid on the glass fibre was found out in terms of strength retention and loss of cations from the glass matrix. The mildness of this acid was accentuated by the fact that 70% or more of the strength was retained at all the conditions employed. A minima in strength retention was observed at 2M acid concentration similar to the trends observed in the past (Betz and Jones 2003 and Jones and Chandler 1986). Leaching of cations reflected this trend. The large strength retention could be related to the fewer amounts of Ca and K leached from the glass matrix (Kumosa and Qui, 1997). Similar to malonic acid, an unusually large amount of B was leached out that could be due to the favourable orientation of the anion with the trivalent ions during the complex formation. Yet again temperature was found to enhance the degradation process. / Next the extent of passivation (if any) showed by malonic acid was investigated using E-glass fibre pre-treated in 5M malonic acid and post treated in known corrosive acids hydrochloric acid and oxalic acid. Passivation of malonic acid was put to test through examination of strength retention of the fibres under these conditions. This segment was carried out as an extension of a finding (a behaviour synonymous to passivation) shown by malonic that surfaced the previous year by the present researcher. Increasing the pre-treatment time showed a great improvement in the retained strength for all the post-treatment acid mediums. Furthermore, while Jones and Betz (2004) featured 20-40% strength retention within a short time frame in 3M HCl, the immense amount of strength retention (60-70%) preceding pre-treatment should definitely be noted. Similarly strength retention of about 80% was observed when post-treated with the severely corrosive oxalic acid. Hence its is clear that passivation can be induced through prolonged pre-treatment in 5M malonic acid that could inhibit the attack of corrosive acid at least for a period of time. / The last fragment of the study focussed on understanding and working out the mechanism behind the reactions between the E-glass fibre and acid medium in terms of kinetics. The acids utilized were 1.5M malonic acid and 3M glyoxylic acid and the assessments were made through the analysis of the weight changes brought about by the acid medium at various temperatures and time frames. In addition leaching patterns of cations were evaluated as this could contribute in achieving the objective. Maximum weight loss reached 4% in glyoxylic acid while that for malonic acid exceeded 20%. The general trend was that the glass fibres lost weight in both acids for a period of time followed by an evident weight gain. Furthermore the weight loss results fit the first order rate law. While the leaching of cations reflects the weight loss for the shorter time frames, steady loss of ions was visible even for the longer time frames where the weight has increased. The weight gain could be explained in terms of binding of anions to certain cations on the glass surface, accounting for the hindrance in the loss of cations at the longer time frames as well. About 50% of weight loss was associated to Ca while 20% was to Al, leaving 6% to B where as the rest of the ions had shown almost insignificant contribution to the weight loss.

Earthquakes are one of the biggest problems in civil engineering all over the world. Due to earthquakes, great disasters in cities with collapsed structures and human losses have been caused. More specific, old buildings that have been built based on old regulations and design building codes do not fulfil anymore the new criteria of seismic designing.In this study, an old building has been evaluated for the seismic load in order to decide if there is a need for strengthening it using retrofitting methods. The seismic evaluation is based on Eurocode 8 and after the application of retrofitting techniques the building fulfilled its seismic design criteria. The existing building is a four-storey, concrete structure that has been built in 1970 and is located in Athens (the capital city of Greece). The seismic evaluation is conducted by using the software Seismostruct.Two analyses are performed in order to evaluate the seismic behavior of the building. First, an eigenvalue analysis is conducted before and after retrofitting. By using this analysis the torsional sensitivity of the building has been checked. Then, using pushover analysis, the comparison of the target displacement (expected displacement of the building for the design seismic action) for each limit state and the displacement of the building when the first member of the building reached the corresponding limit state, is presented. Target displacement must not be greater than this displacement in order to ensure the safety of the building. If the comparison shows that target displacement is greater, the weak links in the facility should be identified and the proper retrofitting method should be applied for the improvement of the seismic behavior of the building. Pushover analysis is conducted before and after the application of retrofitting methods.After performing the eigenvalue and pushover analysis of the existing building it was found that the building was torsional sensitive and shear failures occurred in many beams of the structure. Regarding the bending failures, the target displacement was not greater than the displacement of the building when the first member of the building reached any of the corresponding limit states. Therefore the building was safe against bending failures. With the application of X-shaped steel braces in selected frames, the building had higher stiffness and it was not torsional sensitive but shear failures occurred again in many beams. Furthermore, compressive failures occurred in columns that were connected with the steel braces. Finally, with the application of fibre reinforced plastic jacketing in the members that failed in the previous pushover analysis there were no shear or compressive failures. Finally the structure was safe against seismic actions.The application of retrofitting methods improved the seismic behavior of the building and the structure fulfilled the updated regulations of Eurocode 8 regarding seismic design. This project thesis may give rise to further studies and researches concerning seismic retrofitting and seismic damage prevention.

Рассмотрены конструктивные и технологические решения по усилению изгибаемых железобетонных конструкций композитными материалами на основе углеродного волокна. Выявлены используемые системы для усиления железобетонных конструкций. Проведен сравнительный анализ существующих систем усиления на основе углеродных волокон. Определена экономическая эффективность такого способа усиления для изгибаемых железобетонных элементов. Приведена методика расчета усиления изгибаемых железобетонных элементов композитными материалами. Произведен расчет усиления различными композитными материалами на примере железобетонных элементов: балка, монолитная плита перекрытия. Выполнено сравнение различных вариантов усилений и предложен коэффициент условной полезности, позволяющий экономически обосновать выбор способа усиления и прогнозировать стоимость усиления конструкции. / Design and technological solutions for reinforcing of bending concrete structures with composite materials based on carbon fiber are considered. The used systems for strengthening reinforced concrete structures are re-vealed. A comparative analysis of existing reinforcement systems based on carbon fibers is carried out. The economic efficiency of this reinforcement method for bending concrete elements is determined. The calculation technique for bending concrete elements reinforced by composite materi-als is given. The calculation of reinforcement by various composite materials is made on the example of reinforced concrete elements: a beam and a monolithic floor slab. The comparison of various amplification variants is made and the conditional utility coefficient is proposed, which makes it possible to economically justify the choice of the gain method and to predict the cost of strengthening the structure.

Hydraulic systems are used in many fields of applications for different functions like energy storage in hybrid systems. Generally the mass of hydraulic systems plays a key role especially for mobile hydraulics (construction machines, trucks, cars) and hydraulic aircraft systems. The main product properties like energy efficiency or payload can be improved by reducing the mass. In this connection carbon fiber reinforced plastics (CFRP) with their superior specific strength and stiffness open up new chances to acquire new lightweight potentials compared to metallic components. However, complex quality control and failure identification slow down the substitution of metals by fiber-reinforced plastics (FRP). But the lower manufacturing temperatures of FRP compared to metals allow the integration of sensors within FRP-components. These sensors then can be advantageously used for many functions like quality control during the manufacturing process or structural health monitoring (SHM) for failure detection during their life cycle. Thus, lightweight hydraulic components made of composite materials as well as sensor integration in composite components are a main fields of research and development at the Institute of Lightweight Engineering and Polymer Technology (ILK) of the TU Dresden as well as at the Leichtbau-Zentrum Sachsen GmbH (LZS).

In der vorliegenden Arbeit wird die Steifigkeits- und Festigkeitsauslegung von mittels der Tailored Fiber Placement (TFP)-Technologie hergestellten Faser-Kunststoff-Verbunden (FKV) am Beispiel eines einteiligen Rotors aus kohlenstofffaserverstärktem Epoxidharz (CFK) für den Einsatz in Turbomolekularpumpen (TMP) vorgestellt. Im Vergleich zu anderen textilen Fertigungsverfahren können mit Hilfe der TFP-Technologie Verstärkungsfaserrovings in der Ebene variabelaxial, d. h. mit ortsunabhängiger, frei wählbarer Richtung, definiert abgelegt werden. Die sticktechnische Fixierung der Rovings mit Hilfe eines Nähfadens führt zu Welligkeiten und Materialinhomogenitäten in TFP-basierten Faser-Kunststoff-Verbunden (FKV). Dadurch werden die Materialeigenschaften beeinflusst. Mit Hilfe einer Prozessanalyse in Kombination mit morphologischen Untersuchungen werden in dieser Arbeit die welligkeitsinduzierenden Effekte in TFP-basierten FKV identifiziert und quantifiziert. Darauf aufbauend wird ein mesoskaliges Repräsentatives Volumenelement (RVE) einer TFP-Einheitszelle auf Basis von Finiten Elementen entwickelt. Mit Hilfe des RVE wird es erstmalig ermöglicht, die Dehnungs- und Spannungsverteilung sowie den lokalen Faservolumengehalt in TFP-basierten FKV zu berechnen und daraus wirklichkeitsnahe Materialkennwerte abzuleiten. Darüber hinaus wird anhand des RVE der Einfluss variierender TFP-Prozessparameter auf die resultierenden Steifigkeits- und Festigkeitseigenschaften analysiert. Weiterhin wird der Einfluss des unter Langzeitbelastung eintretenden Matrixkriechens auf die Materialeigenschaften von TFP-basierten FKV untersucht. Anhand der Entwicklungsschritte eines CFK-TMP-Rotordemonstrators werden die Besonderheiten beim Auslegungsprozess für Bauteile aus TFP-Strukturen verdeutlicht. Neben der Erläuterung der Lastfälle von TMP-Rotoren wird die Entwicklung eines lastfallangepassten Faserlayouts unter Berücksichtigung von geometrischen Restriktionen beschrieben. Im Rahmen der Spannungsanalyse auf Basis der Finite Elemente Methode (FEM) erfolgt die Integration der mittels des RVE bestimmten Materialdaten in das FE-Modell schichtweise, entsprechend der verwendeten TFP-Prozessparameter. Die mit dieser Vorgehensweise berechnete Versagensdrehzahl und die ermittelten Eigenfrequenzen konnten in experimentellen Untersuchungen erfolgreich validiert werden. Durch die Integration der ortsaufgelösten RVE-basierten Materialdaten wird erstmalig nicht nur die Struktursteifigkeit, sondern auch die Festigkeit ausgehend von einem variabelaxialen TFP-Ablagemuster in einem TFP-basierten Bauteil vorhergesagt. Mit dem entwickelten TMP-Rotordemonstrator kann die Versagensdrehzahl gegenüber dem Stand der Technik um 45 % gesteigert werden. In der Arbeit wird auch herausgestellt, welche Änderungen der Geometrie von TMP-Rotoren aus FKV nötig sind, um eine werkstoffgerechte, an die orthotropen Eigenschaften von FKV angepasste Gestaltung zu realisieren und damit die Nenndrehzahlen weiter steigern zu können. Diese Erkenntnisse dienen in verallgemeinerter Weise der werkstoffgerechten Auslegung und Fertigung von TFP-basierten FKV-Bauteilen. / The present work demonstrates the stiffness and strength design of fiber reinforced plastics (FRP) made by the Tailored Fiber Placement (TFP) technology using the example of a a turbo molecular pump (TMP) rotor made of carbon fiber reinforced epoxy resin (CFRP). In contrast to other textile preform manufacturing processes, the TFP technology enables the placement of reinforcement rovings in arbitrary direction according to an user defined design path. In this technology a double locked stitch in a zigzag stitch pattern is used to fixate the rovings. The fixation process leads to waviness and material inhomogeneities within the placed rovings resulting in reduced material properties in TFP-based fiber reinforced plastics. The wavinessinducing effects have been identified and quantified by detailed process analysis and morphological investigations. Subsequently, a meso-scaled representative volume element (RVE) of a TFP unit cell based on finite elements was developed. The RVE provides the opportunity to derive realistic material properties by calculating the stress and strain distribution as well as as the local fiber content in TFP-based FRP. In this work, the influence of different TFP process parameters on the resulting modulus and strength has been investigated using the RVE approach. Additionally, long term loading effects leading to a reduced matrix modulus were analyzed numerically with the RVE. Based on the development of the CFRP TMP rotor specific characteristics of the design process for components made of TFP are clarified. Besides the explanation of loading conditions of TMP rotors the progress of a load-adapted fiber layout considering geometrical restrictions is demonstrated. For the stress analysis based on the Finite Element Method (FEM) material data calculated with the RVE according to the applied TFP process parameters have been integrated into the FE model. The numerically determined failure speed and the calculated eigenfrequencies were successfully validated by experimental tests. By implementing TFP specific material data in the FE model, both, the strucural rigidity as well as the strength, were predicted for the first time in a TFP-based component. Compared to the state-of-the-art, the developed TMP rotor offers an increased failure speed by 45 %. Furthermore necessary geometric modifications for FRP based TMP rotors in order to achieve a material-specific design adapted to the orthotropic material properties and thus to further increase the nominal rotational speeds were shown. These findings provide in a generalized way for a material-specific design of TFP-based FRP components.

Kolfiberkompositer är ett av de materialsom utvecklas snabbast just nu. Analogt med att materialet blir billigare och börjar användas i större utsträckning av flygindustrin utvecklas också tillverkningsmetoder för att följa framstegen. Hur material och tillverkningsmetoder sätter krav och påverkar en produkts utformning och prestanda kan vara svårt att definiera. I detta examensarbete har en Design for Manufacturing och Assembly (DFM/A)-metod utvecklats för att under hela produktutvecklingsprocessen kunna ta hänsyn till produktionsaspekter. DFM/Ametoden är framtagen åt Saab Aerostructures med hänsyn till de material som används, deras existerande produktionsprocesser och den produktutvecklingsprocess som finns på företaget. Utifrån litteratur- och fallstudier har en DFM/A-metod som kallas Metod 2015 (M2015) utvecklats. Metoden innehåller en arbetsprocess, konstruktionsriktlinjer samt stödjande DFM/Averktyg. Genom att i hela utvecklingsprocessen ta hänsyn till produktionsaspekter är detta arbetssätt anpassat för att underlätta utveckling av kolfiberkompositkomponenter på Saab. Utöver själva metoden i sig finns allt material som behövs för användning av M2015 sammanställt i en manual som i första hand riktar sig till konstruktören. Genom att skapa en bättre förståelse för produktionsaspekterna hos en konstruktion och tillhandahålla rätt verktyg kan DFM/A-metoden bidra till flera positiva effekter. Användandet av M2015 bör leda till produkter av kolfiberkomposit som är lättare att tillverka vilket i sin tur också bör minska onödiga kostnader, ge högre kvalitet och kortare ledtider. Införandet ställer dock också krav på Saab för att dessa målsättningar ska kunna uppnås. / Carbon fiber reinforced plastic (CFRP) is one of the fastest developing materials right now. Analogously to the material becoming cheaper and being used more widely in the aerospace industry the manufacturing methods have developed to follow the progress. How material and manufacturing method change the requirements and affect a product's design and performance can be hard to determine. This degree project has developed a Design for Manufacturing and Assembly (DFM/A) method to easier take into consideration the production process throughout the product development. The DFM/A method is developed for Saab Aerostructures and is based on their materials, production process and product development process. By studying literature and performing case studies a DFM/A method called Method 2015 (M2015) was developed. The method includes a work procedure, design guidelines and supporting DFM/A tools. By considering the production aspects throughout the development process this method of operation facilitate the development of CFRP products at Saab. In addition to the method itself the materials needed to use M2015 is compiled in a manual for the designer. By creating a better understanding of the production aspects of a design and providing the right tools the DFM/A method can contribute to several positive effects. The use of M2015 should lead to CFRP products that are easier to produce which in turn should minimize unnecessary costs, raise the quality and shorten lead times. However, the implementation of M2015 at Saab also creates demands to reach these targets

Electromagnetic interference (EMI) is one of the most common problems encountered in microwave applications. Interaction of electromagnetic (EM) waves from different sources may result in device malfunction due to misinterpretation of the transferred data or information loss. On the other hand, development of materials with reduced radar detectability is desired in defense applications. Considering the limitations in weight and thickness, development of lightweight structural materials with enhanced electromagnetic absorption potential is needed. In this study, development and characterization of glass fiber-reinforced polymer (GFRP) composite materials to be used in EM wave absorbing or EMI shielding applications was aimed. Incorporation of electromagnetic wave absorption characteristic has been achieved by the application of conductive thin film on fiber glass woven fabric reinforcement layers. Characterization of EM wave absorption potential was conducted using &ldquo / free-space method&rdquo / in 18 &ndash / 27 GHz frequency range. Single and multilayered combinations of surface-modified fiber glass woven fabrics were characterized in terms of their EM wave interaction properties and design principles for efficient broadband EM wave absorbing multilayered GFRP composite material have been presented. A computer aided computation method has also developed in order to predict EM wave transmission, reflection, and hence absorption characteristics of multilayered structures from single layer properties. Estimated results were verified compared to free-space measurement results. In the current study, up to 85% electromagnetic wave absorption has been obtained within 18-27 GHz frequency range (K band). Enhancement of EM wave absorption potential of multilayer structure has also been demonstrated by computer aided computation.