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Polymer composites have various application in automotive industry. Achieving vehicle efficiency in public transportation, among other goals, is often done by lightweight materials like fibre reinforced plastics as structural elements of the vehicle. A concept solution for a V shaped structural floor element of a city bus is proposed in this paper. CAD model of floor structural element has been designed from which, in later phases, construction of complete composite floor will be optimized and designed. Test sample made of hybrid (carbon and glass) fibre composite was produced and tested under the flexural load for comparison with a FEA model. Test sample displacement was measured using a GOM Tritop optical measurement system. Comparison showed that difference between real measurement and FEA for maximal displacement is only 11.7%.

The focus of this research work is to study the effect of hybrid fillers of bamboo fiber and commercial glass fiber on high density polyethylene (HDPE) matrix without interfacial coupling agent. The hybrid composite was formed through melt blending method using two-roll mixing mill at temperature of 160 oC and was shaped using compression molding machine. The highest value of Tensile Modulus at break and Hardness were obtained at hybrid ratio of 70 % of HDPE/ 15 % bamboo/ 15 % glass particles (H/B15/G15). However, the inclusion of the hybrid fillers did not show any significant difference in Impact strength from the molded blank HDPE samples (H/B0/G0) while the percentage water absorbed by the samples predominantly decreased as the content of the commercial glass filler was increase in the HDPE matrix.

The increased industrial use of fibre reinforced composites structures such as sandwich panels is a result of their lightweight, flexible, and high strength capabilities. Sandwich panels are generally assembled by placing a lightweight core in between two facesheets. The core provides the required thickness without increase in weight while the facesheets provide the required strength at less than half the cores thickness. Whilst the material choice for both vary, carbon and glass fibre reinforced polymers are predominantly the two main composite materials commonly utilised in the fabrication of sandwich panel facesheets. New developments in the application of fibre reinforced structures have raised an environmental and economic awareness for the necessity to recycle and repurpose fibre cut-off waste. The UK is the first major economy to pioneer a “green industrial revolution” by passing legislative laws, backed with funding, to bring industries such as the composite industry up to speed to achieve product sustainability and recyclability. With focus in the composite industry shifting towards zero waste production cycles, it becomes a necessity to investigate the mechanical behaviour of fibre cut-off waste in structures such as sandwich panels. This thesis aims to contribute towards the issue by presenting an experimental comparison of sandwich panels fabricated using recycled carbon fibre (RCF) and chopped strand matt glass (CSMG). The experimental work undertaken are three-point bending and low-velocity impact. Across all industry that utilise sandwich panels, the two phenomena mentioned are observed to contribute significantly to panel degradation during its working life. For fair comparison, the sandwich panels for both fibres consist of the same areal density and same manufacturing methods. Novelty in the thesis is granted through the comparative study between the mechanical behaviour of RCF and CSMG sandwich panels as this has not been investigated for industrial application. Obtained experimental data show that the RCF panels are stronger than the CSMG panels which could be an alternative to sandwich panels made with CSMG.

Most widely recognized material in the present world is Concrete due its durability, and strength aspects. Hence by using different additives like Glass fibre and woven biaxial Geogrid the compressive strength test is carried out for M30 and M40 grade of concrete to improve the performance of concrete. The main aim of the present study is to analyze the compressive strength of concrete, when concrete is mixed with glass fiber and Geogrid, to meet the demands of the modern construction. The addition of Glass fibre into concrete increases the compressive strength of concrete than Geogrid concrete. Tests are conducted by using glass fibre and Geogrid. For 1 m3 of concrete 612grams of glass fibre for M30 grade of concrete and for M40 grade of concrete 697 grams of glass fibre for 1m3 of concrete are used. Geogrids are placed at 2 layers (50mm interval each) in a 150*150mm cube in both M30 and M40 grade of concrete.

Fibre-reinforced polymeric composite materials are becoming substantial and convenient materials in the repair and replacement of traditional metallic materials due to their high stiffness. The composites undergo different types of fatigue loads during their service life. The drive to enhance the design methodologies and predictive models of fibre-reinforced polymeric composite materials subjected to fatigue stresses is reliant on more precise and reliable techniques for assessing their fatigue life. The influences of fibre volume fraction and stress level on the fatigue performance of glass fibre-reinforced polyester (GFRP) composite materials have been studied in the tension–tension fatigue scenario. The fibre volume fractions for this investigation were set to: 20%, 35%, and 50%. The tensile testing of specimens was performed using a universal testing machine and the Young’s modulus was validated with four different prediction models. In order to identify the modes of failure as well as the fatigue life of composites, polyester-based GFRP specimens were evaluated at five stress levels which were 75%, 65%, 50%, 40%, and 25% of the maximum tensile stress until either a fracture occurred or five million fatigue cycles was reached. The experimental results showed that glass fibre-reinforced polyester samples had a pure tension failure at high applied stress levels, while at low stress levels the failure mode was governed by stress levels. Finally, the experimental results of GFRP composite samples with different volume fractions were utilized for model validation and comparison, which showed that the proposed framework yields acceptable correlations of predicted fatigue lives in tension–tension fatigue regimes with experimental ones.

The sudden occurrence of an earthquake induces a liquefaction effect on foundation soil, which causes a substantial increase in the uplift pressure acting on piles and causes structural damage to superstructures. This forms the basis of the necessity of experimenting with the behaviour of piles subjected to uplift loads and predicting their load-carrying capacity or resistance. Fibre-reinforced polymer (FRP) wraps are widely used for strengthening and retrofitting piles subjected to damage. The current study is aimed at determining the uplift load-carrying capacity or resistance of piles wrapped with basalt fibre-reinforced polymer (BFRP) and glass fibre-reinforced polymer (GFRP) sheets by experiment. Preliminary tests were conducted to identify the influence of BFRP and GFRP wraps on the mechanical strength properties of concrete. The mechanical strength of the specimen with the double wrapping of basalt and glass fibres in the perpendicular direction outperformed all other specimens. Moreover, the piles were wrapped with laminates and experimented on for their uplift capacity in dry and submerged conditions. The results indicate a considerable improvement in the uplift resistance of the piles compared with the unconfined piles. The BFRP and GFRP wraps improved the uplift resistance of the piles by 35.56% and 15.56%, respectively, higher than the unconfined pile for dry conditions. The angle of the interfacial friction in dry and submerged states was observed to be the maximum for the perpendicular direction for both of the FRP wraps, and the failure modes were compared. The simulated model showed a significant correctness for determining the uplift resistance of FRP-wrapped piles in dry and submerged states. The degree of agreement in the dry condition for the experimental results and finite element method was more than 94% for all fibre wraps.

The present investigation was conducted on the low-speed impact response of quasi-isotropic [±45/0/90°]xs hybrid composite through laboratory level experimental tests. The purpose was to understand the behaviour that the different stacking sequences of hybrid glass/carbon fibre composites has on the ability of the material to sustain loads during low-speed impact events without developing critical structural failure in the material and improving the impact energy absorption properties, which is a relevant matter in aerospace and automotive industries. Drop-weight impact tests were carried out on two different laminates, with different stacking sequences, each of which were 16 symmetric inter-ply hybrid laminates named GC [+45G/−45C/0G/90C]4s and, respectively, G-C [+45G/−45G/0G/90G/+45C/−45C/0C/90C]2s, where G stands for glass fibre and C for carbon fibre. Both were comprised of epoxy matrix reinforced carbon/E-glass fibre woven fabric composites. The outcome of changing the hybrid stacking sequence, on the impact performances, was discussed. The damage morphologies and local failure mechanisms were analysed using visual inspection and a high-resolution laser scanner. Under 33 J impact energy, both tested hybrid composites exhibited approximately 10 kN peak load. Nevertheless, one key parameter, the time to peak load, significantly changed; the damage initiation threshold for GC samples occurred immediately before 6 kN, whereas for G-C samples this threshold appeared much earlier. This type of behaviour was partly connected to the delay in the propagation of delamination and fibre breakage, which was influenced by the high elastic energy absorption of the carbon fibres when compared with the glass fibres. The absorbed energy was higher for GC configuration, whereas a higher DI was observed for samples G-C indicating that a high percentage of the total energy was dissipated through the propagation of in-plane and out-of-plane fibre/matrix cracks. No perforation was observed on either configuration; nevertheless, the damage area significantly changed both in size and appearance from one configuration to another.

In liquid composite molding (LCM) processes a catalyzed resin is forced to flow through a dry fibrous preform, opportunely arranged within a mold. The pressure gradient, positive or negative depending on the particular process, drives the uncured liquid flow at a flow rate which relies on fluid viscosity and preform porosity and permeability. Nowadays, sustainability reasons are pushing the market to the wider usage of natural fibers, such as hemp, jute, flex among others, as an interesting alternative to traditional glass and carbon artificial textiles. This manuscript describes an experimental/numerical approach to analyze the preform permeability and the impregnation flow in the LCM process using different textiles, based on glass, carbon and natural fibers. Unidirectional flow tests were performed using a laboratory scale LCM setup, constituted by a sensed mold in order to dielectrically monitor impregnation and saturation flows. The position of the unsaturated flow front was detected also by means of a camera monitoring the resin flow though milled eyelet sealed using transparent material. The permeability was also numerically inferred using the FlowTex software for all the investigated cases. Numerical and experimental outcomes were finally compared and discussed.

This study was focused on the development of hybrid composed using orange peel particulate dispersed in an unsaturated polyester resin reinforced with chopped strands of E-glass fibers. Orange peel particulate of about 350µm sieve size, of varying weight percentage (3, 6, 9,12 and 15) wt.% and E-glass fiber of constant weight percentage 25.1wt% was used as reinforcements in a polyester matrix. The effect of the orange peel particulate on the physical and mechanical properties of the resulting composite such as tensile strength, bending strength, impact strength and hardness strength was investigated. The results showed remarkable improvement in mechanical properties with increase in percentage of particulate reinforcement. Tensile strength varies from 50.0 to 62.6 MPa, Hardness values varies between 28.6 and 40.8HRB, Impact energy at room temperature, varies between 5.0 to 7.4 Joules, as a function of fiber weight fractions and the flexural strength varies from 74.0 to 85.2 MPa. The best mechanical properties were obtained at 15 Wt.% particulate reinforcements. The results of the physical tests show that the water absorption increases as the weight percentage of the particulate reinforcement increases and the same condition also holds for the density.

Microwave non-destructive testing (NDT) has received extensive attention in recent years owing to its advantages of non-contact and one-sided inspection, no need for a coupling medium or sensors attached on the object surface, low power, good repeatability, a relatively easy measurement setup and no ionising radiation hazards. As an alternative method of traditional X-ray imaging and ultrasonic testing, it has been used for monitoring and evaluation of the structural integrity of fibrereinforced polymer composite structures. This paper provides a comprehensive overview of the microwave-based techniques for glass fibre composites, including material characterisation, strain sensing, surface profiling, near-field and far-field damage detection. First, the electromagnetic properties of glass fibre composites and the microwave penetration capability associated are thoroughly discussed. Then, based on the detection principles, the microwave NDT methods are classified into five categories: near-field detection with an open-ended probe (coaxial line/waveguide), near-field resonance methods, far-field sensing methods, focusing methods and microwave-based thermography (integration with another NDT method). The experimental setup, applications and limitations of each technique are reviewed in detail. Finally, discussions on the research trends are presented, including more accurate theoretical models, damage classification, use of the RFID technique, automated inspection and use in additive manufacturing.

Glass fibre-reinforced polyphenylene sulphide composites were prepared by hot-pressing glass fibre fabrics and polyphenylene sulphide resins. The effects of different polyphenylene sulphide resin forms on the properties of the composites were investigated using scanning electron microscopy, dynamic mechanical analyser, pendulum impact tester and universal testing machine. The results showed that different polyphenylene sulphide resin forms had nearly no effect on the glass transition temperature of the composites, which are all located at about 100 °C. Compared with other polyphenylene sulphide composites, the bending strength of polyphenylene sulphide film composites was the highest, reaching 314.58 MPa, and the impact strength of polyphenylene sulphide particle composites was the highest, reaching 245.4 KJ/m2. The bending strength and impact strength were calculated using a standard fraction, and the highest standard fraction was obtained when the ratio of polyphenylene sulphide film to particle was 1:2. The impact strength and bending strength could be obtained. The impact strength reached 229.8 KJ/m2, and the bending strength reached 284.16 MPa.

In recent years, there has been an increasing demand for engineering materials that possess good mechanical and thermal properties and are cheap an d environmentally friendly. From an industrial and academic point of view, there is a need to study the heat conductivity of newly developed polymer composites and the influence of porosity on the insulation performance of polymer composites. Experimental and theoretical studies were conducted on mainly sisal/glass fibre gypsum composites with different fibre volumes (0, 20, 25, 30, and 35 wt.%). The outcomes from the theoretical model in ANSYS have shown that there is a high possibility to simulate the experimental work and high accuracy for reflecting the experimental findings. Moreover, the results show that natural fibre polymer composites with a high-volume fraction of natural fibres have higher insulation performance than synthetic polymer composites with the same volume fraction of synthetic fibres. Furthermore, the results suggest and support that the improved performance of natural fibre-based composites was due at least in part to the internal porosity of the fibres.

The objective of the project was to investigate the long-term hot/wet performance of Glass fibre Reinforced Epoxy composites used for industrial pipe systems. A large part of the work consisted of the development of test methods for both macroscopic and microscopic level. This resulted in new test methods that were found to be as discriminative as the proven internal ‘finger-print tests’ of FPI, a much more elaborative test. A series of glass fibre products was evaluated both for their resistance to storage in hot environments (‘thermal ageing’) and to long-term hot-wet exposure up to temperatures of 125 C. Furthermore, Carbon Fibre Reinforced Epoxy (CFRP) and Glass Fibre Reinforced Epoxy (GRE) were monitored for their response to long-term hot/wet exposure up to a temperature of 150 C.

The objective of the project was to investigate the long-term hot/wet performance of Glass fibre Reinforced Epoxy composites used for industrial pipe systems. A large part of the work consisted of the development of test methods for both macroscopic and microscopic level. This resulted in new test methods that were found to be as discriminative as the proven internal ‘finger-print tests’ of FPI, a much more elaborative test. A series of glass fibre products was evaluated both for their resistance to storage in hot environments (‘thermal ageing’) and to long-term hot-wet exposure up to temperatures of 125 C. Furthermore, Carbon Fibre Reinforced Epoxy (CFRP) and Glass Fibre Reinforced Epoxy (GRE) were monitored for their response to long-term hot/wet exposure up to a temperature of 150 C.

The additive manufacturing represents a new production method of composites reinforced with a continuous fibre. In recent times, the material produced by this new manufacturing method constituted a replacement for conventional materials&mdash, e.g., steel in many technical areas. As the research on FRTP composites is currently under way, the purpose of this article is to add information to the mosaic of studies in this research area. The scientific articles published until now have focused especially on mechanical testing, such as tensile and bending mechanical testing and their assessment. Therefore, the authors decided to carry out and assess the impact test of the FRTP composites produced by 3D printing because this area offers a large extent of research activities. We observed the influence of the reinforcement in the form of the micro-fibre carbon in the thermoplastic (Onyx) or a continuous reinforcement fibre in the lamina on the specimen&rsquo, s behaviour during the impact load processes. The results of the experimental measurements show that the presence of a continuous fibre in the structure significantly affects the strength of the printed specimens, however, the design process of the printed object has to take into account the importance of selecting a suitable fibre type. The selection of a suitable strategy for arranging the fibre in the lamina and the direction of the impact load against the position of the fibre seem to be very important parameters.

This study investigates the fracture properties of high performance cementitious composites (HPCC) with four different types of fibres and with volume fraction content 3%. The four fibres are steel hooked end (S), polypropylene crimped (PP), basalt chopped (B), and glass (G) fibres. The tests were carried out in accordance with the RILEM recommendations. In order to examine the fresh properties of HPCC the slump flow tests were performed. Twelve fibre reinforced HPCC beam specimens with notch were cast and tested using central point loading experiments. In addition, experimental tests of the compressive strength and splitting tensile strength were carried out. The test results made it possible to obtain representative fracture parameters, such as the equivalent strengths, residual strengths, and fracture energy of fibre reinforced HPCC. The S fibre specimens showed the best performance in terms of workability, compressive strength, tensile splitting strength, and fracture energy at large deflection. On the other hand, G fibre specimens exhibited the best performance in terms of flexural strength, equivalent flexural strength at higher deflection, and residual flexural strength at lower deflection. In terms of equivalent flexural strength at lower deflection and residual flexural strength at higher deflection, basalt fibre specimens performed the best. On the contrary, polypropylene fibre reinforced beam specimens revealed the highest deflection capacity.

Six impact energy values, ranging from 2.5 J to 10 J, were applied to study the impact properties of neat epoxy and bamboo composites, while six impact energy values, ranging from 10 J to 35 J, were applied on bamboo/glass hybrid composites. Woven glass fibre was embedded at the outermost top and bottom layer of bamboo powder-filled epoxy composites, producing sandwich structured hybrid composites through lay-up and molding techniques. A drop weight impact test was performed to study the impact properties. A peak force analysis showed that neat epoxy has the stiffest projectile for targeting interaction, while inconsistent peak force data was collected for the non-hybrid composites. The non-hybrid composites could withstand up to 10 J, while the hybrid composites showed a total failure at 35 J. It can be concluded that increasing the filler loading lessened the severity of damages in non-hybrid composites, while introducing the woven glass fibre could slow down the penetration of the impactor, thus lowering the chances of a total failure of the composites.

There are forecasts for the exponential increase in the generation of carbon fibre-reinforced polymer (CFRP) and glass fibre-reinforced polymer (GFRP) composite wastes containing valuable carbon and glass fibres. The recent adoption of these composites in wind turbines and aeroplanes has increased the amount of end-of-life waste from these applications. By adequately closing the life cycle loop, these enormous volumes of waste can partly satisfy the global demand for their virgin counterparts. Therefore, there is a need to properly dispose these composite wastes, with material recovery being the final target, thanks to the strict EU regulations for promoting recycling and reusing as the highest priorities in waste disposal options. In addition, the hefty taxation has almost brought about an end to landfills. These government regulations towards properly recycling these composite wastes have changed the industries’ attitudes toward sustainable disposal approaches, and life cycle assessment (LCA) plays a vital role in this transition phase. This LCA study uses climate change results and fossil fuel consumptions to study the environmental impacts of a thermal recycling route to recycle and remanufacture CFRP and GFRP wastes into recycled rCFRP and rGFRP composites. Additionally, a comprehensive analysis was performed comparing with the traditional waste management options such as landfill, incineration with energy recovery and feedstock for cement kiln. Overall, the LCA results were favourable for CFRP wastes to be recycled using the thermal recycling route with lower environmental impacts. However, this contradicts GFRP wastes in which using them as feedstock in cement kiln production displayed more reduced environmental impacts than those thermally recycled to substitute virgin composite production.

Technical thermoplastic materials (e.g., PEEK, PPA and POM) are widely used for tribological applications combined with different filler systems (e.g., glass- or carbon fibres) because of their excellent mechanical properties. The friction and wear behaviour of thermoplastics can be specifically improved by solid lubrication systems such as graphite, PTFE and MoS2. Besides these systems, others such as WoS2 and MnS are becoming scientifically interesting. This work investigates the influence of different solid lubricants—alternative metal sulphides and polymer-based—in combination with different glass fibre contents on the tribological behaviour of unfilled PEEK and glass fibre-filled PPA. For this purpose, compounds were produced and injection-moulded into tribological test specimens that were subsequently tested. It is particularly evident for both matrix materials that the solid lubricant SLS 22 shows a 25% wear rate reduction when compared to MoS2 and, in addition, the proportion of fibre content in PPA shows an additional wear rate reduction by a factor of 10. The friction level could be kept at a similar level compared to the usually utilised solid lubricants. The investigations showed the potential use of metal sulphide filler systems in high-performance thermoplastic with enhanced tribological properties as alternatives to the well-established solid lubricants.

This paper presents a novel methodology for predicting the dielectric constant of three-dimensional woven glass fibre-reinforced composites. A well-established approach of deriving the effective dielectric constant is the dielectric mixing formulae (rule of mixtures based), which either provide a single value or offer upper and lower bounds. For composites with three-dimensional fibre architecture, an accurate model considering the three-dimensional effect is needed. Here, the anisotropic effect is revealed using electromagnetic simulation to extract the effective dielectric constant of a model material with unidirectional fibres, which are aligned or orthogonal to the electric field. The rule of mixtures based formulae are evaluated. The most suitable formula selected for each case is then extended to a general case with arbitrary fibre orientation and is further used to characterise the capacitor element of an electromagnetic model for 3D woven composites. The proposed method is compared to measurements to demonstrate the improved accuracy.

Due to the environmental impacts resulting from the production of Ordinary Portland cement (OPC), the drive to develop alternative binders that can totally replace OPC is gaining huge consideration in the construction field. In the current study, attempt was made to determine the strength characteristics of glass fibre-reinforced fly ash based geopolymer concrete. Sodium hydroxide (NaOH) and sodium silicate (Na 2 SiO 3 ) were used as alkaline solutions (for activation of geopolymer reaction) at 12, 16, 20 M. Glass fibres were added to the geopolymer concrete in varying proportions of 0.1–0.5% (in steps of 0.1%) by weight of concrete. A constant weight ratio of alkaline solution to fly ash content of 0.43 was adopted for all mixes. British standard concrete test specimens were cast for measuring compressive strength, split-tensile strength, and flexural strength. Concrete specimens were cured by heating in oven at 90 °C for 24 h and natural environment, respectively. From the results, thermally cured concrete samples had better mechanical properties than the ambient (natural) cured samples. Thermally cured concrete specimen, containing 0.3% glass fibre and 16 M NaoH, achieved a maximum compressive strength of 24.8 MPa after 28 d, while naturally cured samples achieved a strength of 22.2 MPa. There was substantial increase in tensile strength of geopolymer concrete due to the addition of glass fibres. Split tensile strength increased by 5–10% in glass fibre-reinforced geopolymer concrete, containing 0.1–0.5% glass fibre and 16 M NaoH when compared to the unreinforced geopolymer concrete (1.15 MPa).

In this experimental work, the behaviour of unidirectional glass fibre-epoxy composites under a cutting force was studied, in order to better understand the cutting mechanisms of processes involving but not limited to composite materials. Starting from composite panels manufactured by resin infusion process, dedicated specimens were obtained and subjected to a quasi-static punch-shear test. Eight different fibre orientation angles with respect to the direction of the cutting force were considered. For each case, different stress-strain behaviours were observed and discussed. The differences were also investigated, in terms of damage propagation, by means of microscopic observations of the cutting zone.

Environmental awareness and trends to develop sustainable resources have directed much research attention towards kenaf fibre as an alternative reinforcement in composite manufacturing. Numerous studies have been conducted on kenaf and its hybrid composites. Most studies were conducted on kenaf/glass hybrid composites compared to other kenaf/synthetic hybrid composites. Similar with other materials, mechanical properties were the fundamental knowledge identified by the researcher. Limited studies conducted on other properties have restricted the use of kenaf composites to non-structural applications. To extend the potential of kenaf composites to automotive exterior or other critical applications, studies on impact properties can be a valuable contribution in the material field. This review discusses the mechanical and low velocity impact properties of kenaf/glass hybrid composites reported previously. Percentage loading of fibre, the angle of orientation in woven fibres and the chemical treatment applied to the fibre before compounding are the three major parameters that affect the mechanical and impact properties of the composites. This review provides insights into the mechanical and impact properties of kenaf/glass hybrid composites for future research.

By the in-line nanostructuring of glass fibres (GF) during the glass fibre melt spinning process, the authors achieve an electro-mechanical-response-sensor. The glass fibre interphase was functionalized with different highly electrically conductive carbon allotropes such as carbon nanotubes, graphene nanoplatelets, or conductive carbon black. On-line structural health monitoring is demonstrated in continuous glass fibre-reinforced polypropylene composites during a static or dynamic three-point bending test. The different carbon fillers exhibit qualitative differences in their signal quality and sensitivity due to the differences in the aspect ratio of the nanoparticles, the film homogeneity, and the associated electrically conductive network density in the interphase. The occurrence of irreversible signal changes during dynamic loading may be attributed to filler reorientation processes caused by polymer creeping or to the destruction of the electrically conductive paths due to the presence of cracks in the glass fibre interphase. Further, the authors found that sensor embedding hardly influences the tensile properties of continuous GF reinforced polypropylene (PP) composite.

Poster presentation of proposed PhD research including plasma treatment of non-crimp glass fabrics to control the formation of multiple cracks in a composite structure.

[ESP] Los materiales para moldes de inyección de polímeros y materiales compuestos representan un sector económicamente muy relevante debido al gran aumento del número de componentes fabricados a partir de materiales poliméricos obtenidos mediante moldeo por inyección. La selección del material para la fabricación del molde, su composición y tratamientos térmicos, así como las condiciones de mecanizado y endurecimiento, tienen una gran influencia sobre su comportamiento en servicio a lo largo de la vida útil del molde. En la primera parte del presente estudio, a partir de ensayos punzón sobre disco, se ha determinado la relación entre la resistencia al desgaste y la dureza de aceros para moldes obtenidos a partir de bloques de gran espesor, cuya microestructura cambia a lo largo del espesor del bloque, estudiando los principales mecanismos de desgaste que tienen lugar. A continuación, con el fin de determinar el daño superficial que sufren los aceros para moldes en condiciones reales de inyección, se han estudiado distintos tipos de aceros utilizados comercialmente en moldes de inyección de polímeros y materiales compuestos, seleccionando las condiciones de operación para determinar la variación de la rugosidad superficial del acero en función del material inyectado, del número de operaciones sucesivas de inyección y de la orientación del flujo de inyección, mediante técnicas de perfilometría óptica y microscopía electrónica de barrido. Además del daño superficial sufrido por el acero con el número de piezas inyectadas, también se ha determinado la evolución de la rugosidad superficial de los materiales inyectados, polibutilentereftalato (PBT) puro y materiales compuestos derivados de PBT por adición de un 20 o un 50% en peso de fibra de vidrio. En el caso de las piezas inyectadas, se ha caracterizado su microestructura en función del flujo de inyección y de la densidad de fibra, se han determinado sus propiedades térmicas y dinámico-mecánicas, así como la variación de la rugosidad superficial de las piezas inyectadas con el número de operaciones de inyección y con la geometría de las distintas secciones de las piezas. Finalmente, se ha evaluado la resistencia a la abrasión de PBT reforzado con un 50% de fibra, en función del número de piezas inyectadas y de la dirección de rayado con respecto a la orientación del flujo de inyección. [ENG] Mould materials for injection moulding of polymers and polymer-matrix composites represent a relevant industrial economic sector due to the large quantity of pieces and components processed. The material selection for mould manufacturing, its composition and heat treatment, the hardening procedures and machining and finishing processes determine the service performance and life of the mould. In the first part of the present study, the relationship between the hardness and microstructure and the wear resistance of mould steels from large blocks has been studied by pin-on-disc tests, studying the main wear mechanisms. In order to determine the surface damage on mould steels under real injection conditions, different commercial steels have been studied by measuring the variation of surface roughness with the number of injected pieces with different reinforcement percentages and different mould geometries, by using optical profilometry and scanning electron microscopy techniques. It was important to determine the variation of surface roughness of the moulded pieces with the number of injection operations. The materials used were polybutyleneterefatalate pure and reinforced with either 20% or 50% glass fibre. For the different mould designs, the evolution of the glass fibre orientation with injection flow has been determined by image analysis and related to roughness changes and surface damage, both of the composite parts and of the mould steel surface. Finally, the abrasion resistance of the composite parts has been studied by scratch tests as a function of the number of injected parts and of the scratch direction with respect to injection flow and glass fibre orientation., Universidad Politécnica de Cartagena

Revisiones [ES] esumen: La utilización de fibras de vidrio en sustitución del amianto, además de otras aplicaciones, ha contribuido a disminuir drásticamente la incidencia del mesotelioma y otras asociadas patologías asociadas a su utilización. Sin embargo, estudios recientes apuntan a la posibilidad de que su manipulación no se encuentre exenta de riesgos. Metodología: Se realiza una revisión bibliográfica de la literatura científica publicada recientemente en las principales bases de datos bibliográficas biomédicas. Resultados: La principal forma de entrada en el organismo es por vía inhalatoria, por lo que sus principales efectos sobre la salud se producen a nivel de vías respiratorias y su capacidad patogénica depende de su composición química, el tamaño, la biopersistencia y la concentración ambiental. Conclusiones: Existe controversia en la interpretación de resultados de estudios experimentales, aunque muchos autores parecen coincidir en que las fibras 475-glass y la E-glass pueden presentar un mayor riesgo de presentar fibrosis o cáncer pulmonar en animales. La mayoría de estudios en humanos no parece demostrar relación entre exposición con fibrosis pulmonar o la disminución de la capacidad pulmonar, que parecen más relacionadas con el consumo de tabaco. Tampoco existen evidencias claras en cuanto a una posible asociación con determinados cánceres del aparato respiratorio. Estudios recientes sobre efectos citotóxicos y genotóxicos, apuntan a que FMA de diámetro menor de 3 lm y longitud superior a los 5 lm pueden inducir alteraciones en las células A549 del epitelio alveolar de los seres humanos con estrés oxidativo y peroxidación de lípidos de membrana, aunque faltan elementos suficientes que permitan confirmar estos hallazgos. En base a las evidencias existentes en la actualidad, la IARC incluye las fibras de vidrio de filamentos continuos y las lanas de vidrio, roca y escoria dentro del grupo 3 como no clasificables respecto a su potencial efecto cancerígeno y las fibras cerámicas refractarias (FCR) dentro del grupo 2B como posibles cancerígenos para los seres humanos.[EN] Abstract: Among other applications, the use of glass fibre instead of asbestos, drastically contributed to reduce not only the mesothelioma incidence but also the other pathologies associated to its use. According to recent studies it could be that the manipulation is not exempt from the risks. Methodology: a bibliographic scientific literature review was recently published in the main biomedical bibliographic databases. Results: Since inhaling is the major organism entry route, its main health effects impact on the airwaves. Its pathogenic capacity depends on its chemical composition, the size, the biopersistence and the fibres concentration in the ambient. Conclusions: Although many authors seem to coincide that 475-glass fibre and E-glass fibre do represent a higher risk of developing fibrosis or lung cancer in animals, there is a controversy when interpreting the results in the experimental study. Most of the human studies reveal do not connect* between the asbestos exposure to the lung fibrosis or to the lung capacity decrease, which are more related to tobacco consumption. A possible association with particular cancers of the respiratory system it is not clearly verified. Although such discovery is just to be confirmed due to the lack of elements, according with recent investigations on cytotoxic and genotoxic effects, the MMFA, with a dimeter less than 3mm and more than 5 mm length, can induce variations in alveolar epithelia cells line, A549, from humans with oxidative stress and membrane lipid peroxidation. Concerning current evidences, the International Agency for Research on Cancer (IARC) includes the continuous filament glass fibres and glass wool, rock wool and slag wool fibres in group 3 –unclassifiable as to its carcinogenicity to humans and in group 2 the refractory ceramic fibres (RCF) as possibly carcinogenic to humans. No

The study implements the consequential life cycle assessment (CLCA) to provide a market based perspective on how overall environmental impact will change when shifting glass fibres to flax fibres as reinforcements in composite fabrication. With certain assumptions, the marginal flax fibre supply is identified to be a combination of Chinese flax fibre (70%) and French flax fibre (30%). Due to inferior cultivars and coal-fired electricity in Chinese flax cultivation, the CLCA study reveals that flax mat-PP has 0.8–2 times higher environmental impact values than the glass mat-PP in most environmental impact categories over the production and end-of-life (EoL) phases. For purpose of providing potential trajectories of marginal flax fibre supply, additional scenarios: the “all French fibre”, and “all Chinese fibre” are evaluated formulating the lower and upper boundaries in terms of environmental impact change, respectively. A “the attributional fibre supply mix” scenario is supplied as well. All of these scenarios are useful for policy analysis.

The use of polymer fibre reinforced Composite materials is finding applications day by day in engineering fields such as aero-space, automotive, aircrafts constructions, etc. Glass fibre polymer composites are reinforced with granulated blast furnace slag (GBFS) ball milled to size of 5 nm in different weight fractions, i.e. (0%, 5%, 10% and 15%) and fabricated by using hand lay-up technique. These fabricated slabs are cut into required dimensions and the tests for mechanical properties like Tension test, Compression test, Flexural test Impact test and Hardness test were performed. Tension test, compression test and Flexural test were performed on Computerized Universal Testing Machine (UTM), Impact test was performed for Izod and Charpy specimens and Hardness test was performed on Brinell's Hardness Testing Machine. From the experimental results obtained, it was noticed that the mechanical properties were enhanced when the blast furnace slag percent was increased and also among these percentages of blast furnace slag, the specimen having 15% was possessing highest properties.

Multi-layered glass and carbon-reinforced polymer composites may exhibit unique properties comparatively with the benchmark, proven they are being tailored bounded by several requirements. The paper herein approaches issues on the influence of the various contents and orientation of UD carbon fibre constitutive on the mechanical, dynamical and thermal expansion if embedded along with glass fibres in different stacking sequencing within an unsaturated polymer resin. The results show that the architectures with the highest content of carbon fibres (e.g. GF:CF(60:40) – 0° and 90°) provide the best tensile and flexural properties, and behave better under dynamical loading conditions and temperature variations, no matter the orientation directions. In addition, it was shown that a thorough understanding can be attained, with respect to the UD carbon fibre content, and different orientations influence on the overall composite material properties, taking into account the data retrieved from dynamical and thermal expansion runs.

A comprehensive program of experiments consisting of compression, uniaxial compression, direct shear, flexural as well as splitting tensile and air permeability tests were performed to analyse the effect of the level of fibre dosage and the water&ndash, cement ratio on the physical properties of hybrid fibre-reinforced concrete (HFRC). Two types of fibres were studied in terms of their effect on the properties of HFRC. The results indicated that the mechanical properties of concrete were significantly improved by increasing the fibre content. However, increasing the percentage fibre content past a certain peak performance limit (0.9% glass fibre (GF) and 0.45% polypropylene fibre (PPF)) led to a decrease in strength compared to reference mixes. Additionally, the incorporation of hybrid fibres yielded an increase in air permeability in the tested specimens. The results showed that the strength-related properties of HFRC were superior to the properties of single fibre-reinforced concrete.

Journal article Tidal turbine blades are subjected to significant thrust and torsional loadings due to the high density ofthe seawater in which they operate. These thrust loadings lead to high bending moments at the bladeroot, which can prove to be a serious design constraint for these devices and can have implications withrespect to cost-effectiveness and scalability. This work presents a combined hydrodynamic-structuraldesign methodology for a commercial scale (1.5 MW) tidal turbine. A hydrodynamic analysis of theblade is carried out to determine force distributions along the blade span under normal and extremeoperating conditions. Using output from the hydrodynamic model, a pre-processor for computing bladestructural properties is used to determine the strain distribution along the blade spar caps. The straindistributions from this analysis are then compared with a finite element model of the blade which is thenused to compare the structural performance of glass fibre reinforced polymer (GFRP) and carbon fibrereinforced polymer (CFRP) as spar cap materials. peer-reviewed

Three types of polyethylenes (low density: LDPE, medium density: MDPE, and high density: HDPE) were used to investigate the effect of chain branching on the dispersion and adhesion in Glass fibre reinforced polymer composites. The interaction between the polyethylene matrix and the Glass fibres was investigated in terms of differences in mechanical behaviour, morphological characteristics, rheological and thermal properties between the three polymer composites systems. Addition of Glass fibres enhanced the mechanical properties for all systems. The degree of enhancement, however, depended on the branching and crystallinity of each polymer. The long chain branching (LCB) in LDPE resulted in higher increases both in the Elastic (Young’s) modulus in the solid state and in the Storage modulus in the melt. The higher crystallinity of HDPE was responsible for higher increase in tensile strength and less fibre pull-out upon addition of Glass fibres. Rheological results also confirm the same observation for LCB. The addition of Glass fibres also resulted in improved thermal stability of the various polyethylene samples.

A novel re-formative polymer composite manufacturing route has been developed by UK and Qatar-based Universities. This novel process recycles domestic-waste thermoplastic material, without the requirement for intensive filtering or washing operations. The produced polymer can be reinforced with recycled glass fibres, forming a structurally load-bearing composite, which may potentially be suitable for use in applications, including utility poles, railway sleepers, and fencing. Thus, infra-red (IR) analysis showed the presence of polypropylene (PP), polyethylene (PE), and polyethylene terephthalate (PET) in the commingled material. Differential scanning calorimetry (DSC) was used to determine glass transition temperatures and melting temperatures of each of the associated polymer types. Dynamic mechanical thermal analysis (DMTA) was used to determine the storage and loss modulus of the bulk commingled component. Lastly, flexural and tensile strengths of the re-formative polymer with differing proportions of glass fibre were assessed, giving a range of strengths at each glass fibre proportion for possible compositional variation in the polymer type. The recycled polymer is considered a viable structural material for replacing both wooden and concrete components, generating a polymer recycling route with concomitant environmental benefits. This plastic recycling route therefore offers a solution towards achieving climate change targets with a purposeful end-product component.

This paper deals with an experimental investigation on the bearing failure load of glass fibre/epoxy (GFRP) laminates. The effects of fibre-to-load inclination angle and laminate stacking sequence on the bearing load capacity have been determined experimentally on two different type of laminates: unidirectional and bi-directional (cross-ply). Significant reductions in bearing failure load when fibre inclination angle increases are highlighted. Bearing design formulas are also proposed based on the results of the experiments.

The behaviour of fibre reinforced polymer (FRP)‐confined concrete in circular columns has been extensively studied, but much less is known about concrete in FRP‐confined square columns, in which the concrete is non‐uniformly confined and the effectiveness of confinement is much reduced. The present paper deals with the analysis of experimental results in terms of load‐carrying capacity and strains, obtained from tests on square prismatic concrete column, strengthened with external glass fibre composite. The parameters considered are the number of composite layers and the corner radius for a square shape. A total of twenty‐one prisms of size 100 × 100 × 300 mm were tested under strain control rate of loading. Santrauka Pluoštu armuotu polimeru sustiprintų apskritų betoninių kolonų elgsena yra išsamiai išnagrinėta. Daug mažiau žinoma apie polimero pluoštu sustiprintų kvadratinių betoninių kolonų elgseną. Tokiuose elementuose betono deformacijos suvaržomos nevienodai. Dėl to mažėja sustiprinimo efektyvumas. Straipsnyje pateikiami išoriniais stiklo pluošto lakštais sustiprintų kvadratinių betoninių kolonų laikomosios galios, deformacijų eksperimentinių tyrimų rezultatai ir jų analizė. Eksperimentiniuose tyrimuose nagrinėta kompozitinių pluoštų sluoksnių skaičiaus, skerspjūvio kampo spindulio įtaka sustiprintų kolonų elgsenai. Iš viso išbandytos dvidešimt viena 100×100× 300 mm matmenų prizmės. Bandymai atlikti kontroliuojant apkrovimo greitį pagal deformacijas. First Published Online: 14 Oct 2010 Reikšminiai žodžiai: betoninė kolona, kvadratinis skerspjūvis, sustiprinimas, stiklo pluoštas, gniuždomasis stipris, ribinė deformacija.

We present a new experimental technique to allow laboratory-scale observation of underwater blast loading on circular plates, including dynamic deformation and failure of the plates as well as the sequence of cavitation events in water. The apparatus is used to measure and compare the responses of a quasi-isotropic glass/vinylester composite and of a woven carbon/epoxy plate. Dynamic explicit FE simulations are conducted and their predictions are found in good agreement with experiments. Measurements and FE predictions are used to validate a recently developed theoretical model for the response of elastic orthotropic plates to underwater blast.

Dynamic rheological parameters such as storage modulus, G’, loss modulus, G”, and dynamic viscosity, h’, at 200°C were studied for Kevlar fibres, glass fibres and their hybrids reinforced linear low density polyethylene (LLDPE). Parallel plate rheometer was employed for these tests. G’, G” and h’ increased with the increased reinforcement and angular frequency, w. Two sets of reinforcement, 10 and 20 vol.% of fibres are used in LLDPE. The composition of fibres in hybrid composites was varied. The replacement of glass fibres with Kevlar increases the values of G’, G” and h’. The values of these rheological parameters also increased with the thickness of the composite. This increase was associated with the decreased average orientation of fibres present in the composite. The effects of the change in strain amplitude on G’ and G” is also studied and reported here.

International audience; This paper presents results from a study of the wet aging of four thermoset resins and their [0°/90°] stitched glass fibre reinforced composites. The matrix resins are orthophthalic polyester, isophthalic polyester, vinyl ester and epoxy. Resins and composites were aged for 18 months, under three immersion conditions: 20°C sea water, 50°C sea water and 50°C distilled water. Tensile tests,on resins and at 45° to fibre direction of composites, both before and after aging enable the influence of matrix resin and aging medium on weight changes and matrix dominated property degradation to be evaluated. This has enabled a unique data set to be obtained. A large part of the shear property loss after aging is recovered after drying. An original application of damage mechanics parameters is used to quantify the changes in composite shear behaviour, in order to provide a more complete representation of the inelastic response.

Glass fibre reinforced polymers (GFRP) are obvious candidate materials for use in the structures of ocean energy devices due to their corrosion resistance, high strength and low cost. The polymers normally used in GFRP can absorb up to 5% water by weight when immersed for long periods and this can reduce the tensile strength of the material by 25% or more. The thesis describes a combination of experiments and modelling studies undertaken to (i) quantify the degradation in fatigue strength due to moisture saturation in a number of candidate materials, (ii) seek to understand the damage mechanisms which are important in the degradation of the material strength by moisture saturation and (iii) predict the degradation in tidal turbine blade life due to water saturation. The experimental work involved the fabrication of quasi-isotropic (QI) coupons of vinyl-ester or epoxy / E-glass and vinyl-ester / Advantex-glass using the vacuum assisted resin transfer moulding process followed by post curing at elevated temperature for 4 hours to ensure full cure of the laminate. Approximately one half of those coupons were acceleration aged in warm water for up to 2 years to simulate immersion in 12° C seawater for 15 to 20 years. The rest were stored at normal room temperature and humidity for a similar length of time. Constant amplitude fatigue testing of both dry and wet coupons established the stress-life curves for the materials and thereby quantified the degradation in the fatigue strength due to water saturation of the materials. The modulus of the coupons was also monitored during the fatigue testing to establish the damage levels due to fatigue cycling. A number of other experimental studies were also performed to investigate the effects of applied stress during ageing and different glass fibre material on the fatigue strength of the material. A preliminary fatigue design methodology for tidal turbine blades was developed using a tidal velocity model, a hydrodynamic forces model, a structural finite element model and a strain-life fatigue model. The methodology is applied here for the preliminary design of a three-bladed tidal turbine concept, including tower shadow effects, and comparative assessment of pitch- and stall-regulated control with respect to fatigue performance. This methodology was also used to predict the effect of moisture saturation on blade life for both pitch- and stall-regulated turbines. A multiaxial fatigue damage model for fibre reinforced polymer composite materials has also been developed. The model combines (i) fatigue-induced fibre strength and modulus degradation, (ii) irrecoverable cyclic strain effects and (iii) inter-fibre fatigue. The inter-fibre fatigue aspect is based on a fatigue-modified version of the Puck multiaxial failure criterion for static failure. The model is implemented in a user material finite element subroutine and calibrated against fatigue test data for unidirectional glass fibre epoxy. Validation is performed against the fatigue tests on epoxy / E-glass coupons in the experimental programme. The model is successfully validated across a range of stress levels. The model predicts both modulus degradation and fatigue life of GFRP laminates during constant amplitude fatigue cycling. It also predicts the fatigue strength knockdown factor due to moisture saturation of the materials.

Ponencia presentada al I Simposio de la red española de análisis de ciclo de vida. ACV & Bioenergía, CIEMAT, Madrid 15 de octubre de 2013 Alife cycle assessment (LCA) for fibre-reinforced polymers consisting on glass fibre and pbenoltc resin with a brominated flame retardant additive ts presented. Due to its toxicity and difficulties in recycling, new environmental friendly matertals are being designed. lt is intended that this LCA. which is based on new data lffe cvcre inventory (LCl) serves as a benchmark.LCA results obtained with these new LCI are campared with results from lCI of cornrnercial database. The environmental impacts assoclated with energy consumption and air emissions were assessed, as well as other environmental impacts resulting from the extraction and processing of materials and fibre-reinforced polymers manufacturing. End-ot-llfe scenarios for recycling, incineration and landfilling,including the environmental impacts of brominated trame retardants,were also compared for this material. Se presenta el análisis del ciclo de vida (ACV) para un polímero de resina tenóltca reforzado con fibras de vidrio y con retardante de llama bromados como aditivo. Debido a su toxicidad y dificultades en el reciclaje, se están buscando nuevos materiales alternativos. Se pretende que este ACV, que está basado en datos de nuevos inventarios del ciclo de vida (ICV) sirva como base de comparación. Los resultados del ACV obtenidos con estos nuevos ICV se comparan con los resultados de ICV de bases de datos comerciales. Se han evaluado los impactos ambientales asociados al consumo de energía y emisiones al aire, así como otros impactos resultantes de la extracción y procesado de los materiales y fabricación de los polímeros.Además, se han comparado tres escenarios de fin de vida: reciclaje, incineración y disposición en vertedero, incluyendo en todos ellos los impactos ambientales de los retardantes de llama bromados.

This study reports the feasibility of reusing glass fibre waste resulting from the thermolysis of polyester fibreglass (PFG) to produce a glass-ceramic material. PFG was treated at 550ºC for 3 h in a 9.6 dm3 thermolytic reactor. This process yielded a solid residue (≈68 wt.%), an oil (≈24 wt.%) and a gas (≈8 wt.%). The oil was mainly composed of aromatic (≈84%) and oxygenated compounds (≈16%) and had a fairly high gross calorific value (≈34 MJ kg-1). The major PFG degradation products were styrene, toluene, ethylbenzene, α-methyl styrene, 3-butynyl benzene, benzoic acid and 1,2-benzenedicarboxylic acid anhydride. The gas contained basically CO2 and CO; the hydrocarbon content was below 10 vol%. The higher gross calorific value of the gas was low (26 MJ Nm-3). The solid residue (97 wt% fibreglass, 3 wt% char) was converted into a glass-ceramic material. For this, a mixture consisting of 95 wt% of this solid residue and 5% Na2O was melted at 1450ºC to obtain a glass frit. A powder glass sample (

Rodrigues FB, Paranhos MPG, Spohr AM, Oshima HMS,Carlini B, Burnett LH Jr. Fracture resistance of root filledmolar teeth restored with glass fibre bundles. InternationalEndodontic Journal, 43, 356–362, 2010. Aim To evaluate the effect of unidirectional or wovenglass fibre tapes inserted into MOD cavity preparationson the fracture resistance of root filled molar teeth.Methodology Extracted human molar teeth wererandomly divided into six groups (n = 15) : G1 – soundteeth, control; G2 – MOD cavity preparation; G3 –MOD + root canal treatment (Endo); G4 – MOD +Endo + composite resin restoration (Resin); G5 –MOD + Endo + unidirectional fibre (UF) + Resin; G6 –MOD + ;Endo + woven fibre (WF) + Resin. The teethwere subjected to a compressive fracture test in auniversal testing machine. After testing, two failuremodeswereclassified:pulpchamberfloororcusp.Results The highest and the lowest mean fracturestrengths were found in sound teeth (G1) (4960N) andMOD + root canal treatment (G3) (612.84N), respec-tively, with significant differences from the othergroups (P < 0.05). The remaining groups had statisti-cally similar means. In G5 and G6, there was atendency for fracture to occur in the pulp chamber floorcompromising tooth integrity.Conclusions The insertion of glass fibres into MODcavity preparations and restoring them with compos-ite resin was not different than molar teeth filled withcomposite resin only in terms of fracture resistance.Fibres placed into MOD cavities do not reinforceteeth.Keywords: composite resin, endodontic therapy,fracture resistance, glass fibre, molar teeth.

Tez (Yüksek Lisans) -- İstanbul Teknik Üniversitesi, Fen Bilimleri Enstitüsü, 2008, Thesis (M.Sc.) -- İstanbul Technical University, Institute of Science and Technology, 2008, Plastik parça imalatında kullanılan hammaddeler oldukça geniş bir yelpazeye sahiptir. Ayrıca ana polimer gruplarının altında bir takım katkılar ile fiziksel özellikleri kuvvetlendirilmiş alt polimer türleri geliştirilmiş ve halen geliştirilmeye devam edilmektedir. Plastik katkılarının en önemlilerinden biri hiç şüphe yoktur ki kullanıldığı malzemenin mukavemetini ciddi oranda arttıran cam elyafıdır. Plastik enjeksiyon için üretilen termoplastik granüllerinde kısa lifler kullanılmaktadır. İmalatı yapılacak olan parçanın mukavemetinde, bu kısa liflerinin ne yönde yoğunluk gösterecekleri çok önemlidir. Elyaf yönlenmelerinde akış geometrisi önemli bir rol oynamaktadır. Dolayısıyla akış geometrisini belirleyen unsurlardan en önemlisi olan yolluk giriş noktası, elyaf takviyeli malzemelerin mekanik özelliklerinde etkilidir, ve kalıp tasarımı esnasında bu kriter göz ardı edilmemelidir. Bu çalışma da plastik enjeksiyon ile imal edilen cam elyafı takviyeli bir plastik parçada liflerinin yönlenmesi araştırılmıştır. Bu amaç ile örnek bir parça üzerinde sayısal ve deneysel incelemeler yapılmıştır. İmal edilen parçadaki elyaf yönlenmesi sayısal çözümler ile karşılaştırılarak gerek kalıp tasarımı esnasında kullanılan sayısal benzetimlerin kullanışlılığı, gerekse elde edilen parçanın malzeme özellikleri irdelenmiştir. Enjeksiyon kalıbı tasarımında kullanılan sayısal benzetimlerin, yolluk giriş noktasının seçimi sayesinde elyaf yönlenmesini yönetmede nasıl kullanılacağı tartışılmıştır., There exists a wide range of raw material choices in plastic part production. Furthermore, under than the main polymer branches, sub branches were and being improved with additives which changes the physical properties of the plastic parts. One of the most important additive, with no doubt, is fiber, which improves the strength of the parts significantly. Thermoplastic granules, used in plastic injection, are produced with short fibers. Short fiber orientation is very important for the strength of the part. Flow geometry takes the major role in orientation. Most important fact which affects the flow is the gate location, has an influence on the mechanical properties of the materials with fiber additives. This point must be considered in mold design. In this thesis, fiber orientation in a plastic part with fiber additive was studied. For this purpose, numerical and experimental studies were done on a sample plastic part. Numerical predictions were compared with the actual produced parts; both the numerical simulations being used for mold design and material properties were examined. How numerical simulations should be used in deciding the injection point, correspondingly affecting the fiber orientation, was discussed., Yüksek Lisans, M.Sc.

Current research literature on coatings for building applications make evident the existence of important damage both in outdoors and indoors applications when the paint is used without any reinforcement because of several reasons: the low quality of some paint components, coatings extremely thin, and the unskilful of painters. This article studies the behaviour of some industrial paints for indoors and outdoors applications when reinforced with different gravimetric fractions of dispersable short cut glass fibre yarns. Jt is also studied the support influence (cement mortar, plasterboard and laminated plasterboard) and the application method (handy or sprayed). A better performance and durability is obtained for the fractions by weight which are determined for each type of paint, support and application method. Neither the paint colour properties nor the brightness and texture get worse when these gravimetric fractions of glass fibre are added lo the paint. La presente investigación estudia la viabilidad del empleo de refuerzos de fibra de vidrio para pinturas de interior y exterior con el fin de paliar parte de las patologías observadas en aplicaciones arquitectónicas. Se ha seleccionado un tipo de fibra de refuerzo dispersable y se ha estudiado el comportamiento de tres tipos de pinturas (temple, plástica y de impermeabilización) para fracciones gravimétricas crecientes de refuerzo y distintos procesos de aplicación de la pintura. Se ha conseguido mejorar las propiedades de las pinturas industriales que existen en el mercado para aplicaciones interiores y exteriores en edificación elevando las propiedades mecánicas y de durabilidad de dichas pinturas, sin que ello suponga ningún cambio significativo en las cualidades de la pintura, como son la colorimetría, el brillo y el espesor de película.

Composite materials have been subjected to moderate temperature and high sunlight doses of radiation for long periods of time. All tensile mechanical characteristics increase at moderately high temperature, in accordance with a damped increasing exponential model. Sunlight exposition yields ageing on all mechanical properties, in agreement with a damped decreasing exponential model. These mechanical properties loses in fire-resistant composites are less than standard resin composites ones. Toughness characteristics show loses stronger than strength ones. Se han sometido diversos materiales compuestos a exposiciones prolongadas a temperatura moderadamente alta y a fuertes dosis de radiación solar. Se ha comprobado que todas las características mecánicas a tracción aumentan por efecto continuado de temperaturas moderadas, de acuerdo a un modelo exponencial creciente amortiguado. La exposición prolongada a la radiación solar produce un envejecimiento de todas las características a tracción. Éstas disminuyen según un modelo exponencial amortiguado. Las pérdidas son menores en compuestos con resinas ignífugas que con resinas normales. Los indicadores tenaces experimentan pérdidas más intensas que los indicadores resistentes.

International audience; This work aims to analyse the influence of the fibre/matrix interface on the acoustic response of commingled yarn thermoplastic composites submitted to transverse tension and mode I fracture mechanics loading. For this purpose, different interfacial qualities were obtained by modification of the fibre reinforcement sizing and the matrix coupling. The acoustic emission rate (number of acoustic events emitted per time unit) has appeared suitable to quantify the damage involved by the mechanical loading according to the interfacial quality. The comparison of the acoustic emission obtained for the two loading modes has shown that, although the amplitude range [59-66dB] is characteristic of interfacial debondings in transverse tension, it is no more the case for a mode I delamination test for these commingled GF/PP composites.

This study evaluates the slurry-erosion wear of glass fibre reinforced vinyl ester composites (VE-FRP) using a high speed slurry-pot type wear tester. The wear rates of VE-FRP were compared using different abrasives, namely quartz, chromite, copper ore, zinc concentrate, and tailings. Furthermore, the effect of abrasive particle size and slurry concentration on the VE-FRP wear was studied. The erosion wear results of VE-FRP were compared to natural rubber (NR) and bromobutyl rubber (BIIR) as well as to few common thermoplastics, such as polypropylene (PP) and polyvinyl chloride (PVC). Moreover, the failure characteristics of VE-FRP were analyzed. The results demonstrated that coarse quartz produced the largest wear rates on VE-FRP samples, while the zinc concentrate showed the lowest wear. Minor changes in the abrasive particle size had no effect on the wear results, only when the particle size was markedly raised, the wear started to increase. When comparing the wear rates of different materials, it was concluded that with all abrasive types, tested rubbers and thermoplastics had lower wear rates than VE-FRP. acceptedVersion

The notch and strain rate sensitivity of noncrimp glass fibre/vinyl-ester laminates subjected to uniaxial tensile loads has been investigated experimentally. Two set of notch configurations were tested; one where circular holes were drilled and another where fragment simulating projectiles were fired through the plate creating a notch. Experiments were conducted for strain rates ranging from 10-4/s to 102/s using servo hydraulic machines. A significant increase in strength with increasing strain rate was observed for both notched and unnotched specimens. High speed photography revealed changes in failure mode, for certain laminate configurations, as the strain rate increased. The tested laminate configurations showed fairly small notch sensitivity for the whole range of strain rates. QC 20150506