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Al-Azzawi, Ahmad. "Analysis of static and fatigue damage in aluminium/GFRP hybrid composites." Thesis, Cardiff University, 2017. http://orca.cf.ac.uk/106742/.
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This study has focused on investigating the initiation, propagation and effects of damage in fibre-metal laminates (FMLs) specifically Glare® 4B under buckling, postbuckling and high cycle fatigue through the use of novel numerical and experimental techniques. In terms of numerical analysis, a 3D user-defined cohesive zone model (CZM) has been generated to simulate delamination initiation and growth in specimens under static compressive stresses, using the software Abaqus. The generated models have been validated using a comprehensive literature review in order to gather reliable mechanical properties for the Glare® material constituents. Following this, a modified cohesive zone model (CZM) based on a trapezoidal traction-separation law has been developed by the author to simulate damage evolution under high cycle fatigue loading. This model was implemented through a user-written VUMAT subroutine working through the interface of Abaqus/Explicit software. This model is able to simulate elastic-plastic interfacial damage behaviour and as such is suitable for ductile adhesives including toughened epoxy unlike bilinear cohesive zone models which can only accurately simulate damage in brittle adhesives. This makes it suitable for modelling any material interface which incorporates ductile adhesives. The numerical buckling results were validated using a series of experimental tests conducted on Glare® 4B specimens containing splice and doubler features in addition to flat specimens containing artificial circular delamination manufactured by Airbus Germany, demonstrating the ability of the models developed to predict the onset and propagation of damage. Experimental fatigue tests were then implemented on Glare® 4B specimens containing splice and doubler features manufactured in-house, to Abstract iii obtain fatigue life for these types of joints, with fatigue parameters extracted from literature on similar grades of Glare® used to validate the trapezoidal traction-separation law based cohesive zone model. Static tests were monitored using Digital Image Correlation (DIC) to provide full-field displacement data and Acoustic Emission (AE) for the detection and location of the damage using traditional AE analysis and novel Delta-T techniques respectively, with Acoustic Emission (AE) using traditional AE analysis technique being used for damage detection under fatigue loading. Finite element models were also generated to model the buckling and postbuckling behaviour of Glare specimens containing splice and doubler joints and showed good agreement with experiments in terms of in-plane and out-of-plane displacements. In experiments, artificial delaminations representative of those which could potentially be generated during manufacturing had a negligible effect on the compressive strength of specimens. Acoustic Emission (AE) was successfully used to detect and locate damage initiation and propagation under buckling loads. Of particular importance in this body of work are the implementation of a trapezoidal traction separation model to predict the initiation and propagation of damage in elastic-plastic materials such as the resin used in the Fibre Metal Laminate Glare under high cycle fatigue and the detection and location of this damage using a bespoke mapping algorithm for the interpretation of Acoustic Emission data.
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Manger, Christopher I. C. "Failure of notched woven GFRP composites : damage analysis and strength modelling." Thesis, University of Surrey, 1999. http://epubs.surrey.ac.uk/738/.
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Eitel, Amy Katherine. "Performance of a GFRP reinforced concrete bridge deck." online version, 2005. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=case1102014072.
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Munagala, Praveenkumar. "Fatigue life prediction of GFRP composite material at coupon and component level." Morgantown, W. Va. : [West Virginia University Libraries], 2005. https://eidr.wvu.edu/etd/documentdata.eTD?documentid=4437.
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Thesis (M.S.)--West Virginia University, 2005.<br>Title from document title page. Document formatted into pages; contains xi, 101 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 84-89).
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Vadlamani, Deepika. "Strain energy density based failure criterion for GFRP coupons under tension and bending." Morgantown, W. Va. : [West Virginia University Libraries], 2007. https://eidr.wvu.edu/etd/documentdata.eTD?documentid=5221.
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Thesis (M.S.)--West Virginia University, 2007.<br>Title from document title page. Document formatted into pages; contains xxii, 209 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 207-209).
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Zhu, Honggang. "Development of epoxy-organoclay nanocomposite as high performance coating and as matrix material of durable GFRP composite for civil engineering applications /." View abstract or full-text, 2009. http://library.ust.hk/cgi/db/thesis.pl?CIVL%202009%20ZHU.
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Tassinari, Aurelio. "Bond behaviour and kb factor in GFRP rebars casted in concrete." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2019.
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A proper bond between reinforcement and concrete is key for an appropriate composite action of both materials in reinforced concrete structures. However, to-date limited studies exist on bond of fiber reinforced polymer (FRP) bars in concrete members under flexure. In this paper, the bond strength developed by FRP and steel rebars is evaluated and compared, by testing reinforced concrete beams under three point bending load. The investigation included several beams that were 183 cm long × 15 cm wide × 36 cm deep: many of them were reinforced with sand coated GFRP rebars, while steel was used to reinforce the remaining ones. For each of the reinforcing systems, various different embedded lengths were tested. The beams were tested under a 3-point-bending setup and they were monitored using several measuring devices: LVDTS, potentiometers and strain gauges. Preliminary results show that the GFRP rebars have lower bond capacity than the ones made of steel. Moreover, it was inferred that the embedded lengths suggested by actual code provisions for GFRP rebars are too conservative.
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Oluwabusi, Oludare E. "Assessing the In-plane Shear Failure of GFRP Laminates and Sandwich Structures." University of Dayton / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1544528074090494.
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Abdi, Yussuf Yusuf, and Ibrahim Zand Jalal. "FRP:s användning inom brokonstruktioner." Thesis, KTH, Byggteknik och design, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-259362.
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I dagsläget är de flesta broar i Sverige tillverkade med betong eller stål. Dessa broar är många gånger förknippade med stora kostnader som ofta beror på underhåll och reparation. FRP, som står för Fiber Reinforced Polymer, är ett relativt nytt material i bärande stommar men är ett väl etablerat material i förstärkningssammanhang. I Europa och i synnerhet Nederländerna finns det flertal broar byggda i FRP. Men på grund av brist på normer och regelverk att luta sig emot sker det sällan någon form av brokonstruktion med FRP i Sverige. Detta examensarbete syftar till att undersöka befintliga normer och studera hur materialet FRP används vid förstärkning och konstruktion av broar. Vidare syftar även arbetet till att undersöka egenskaperna hos FRP som byggmaterial och jämföra det med konventionella material som stål och betong. FRP, också benämnd fiberkomposit, är ett kompositmaterial som kan sammanställas på flera olika sätt. Genom olika material som kombineras och olika tillverkningsprocesser som används kan man på så sätt ge individuell utformning till materialet för dess användning. Fördelarna med FRP är många, men i allmänhet har det god styrka, god beständighet samtidigt som det har en låg vikt. Detta resulterar i att inom brokonstruktion så ger det strukturen en minskad egenvikt, vilket i sin tur underlättar en mängd olika saker. Detta arbete visar på att FRP-material har fördelaktiga egenskaper och kan i vissa situationer vara mer gynnsamt att använda än stål eller betong. Dock som tidigare påpekat saknas det specifika Eurokoder för detta material. Däremot är vi säkra på att introduktionen av en ny Eurokod samt med uppmuntran från myndigheter kommer användningen av FRP inom brokonstruktion utan tvekan öka.<br>At present, most bridges in Sweden are made with concrete or steel. These bridges are often associated with high costs, which often depend on maintenance and repair. FRP, which stands for Fiber Reinforced Polymer, is a relatively new material in load-bearing structures but is a well- established material in the context of reinforcement. In Europe and in particular the Netherlands, there are several bridges built in FRP. But due to a lack of norms and regulations to lean against, there is rarely any kind of FRP bridge construction in Sweden. The aim of this thesis is to examine existing norms and study how the material FRP is used in the reinforcement and construction of bridges. Furthermore, this thesis also aims to investigate the properties of FRP as building material and compare it with conventional materials such as steel and concrete. FRP, also called fiber-composite, is a composite material that can be assembled in several different ways. Through various materials that are combined and different manufacturing processes used, one can thus provide individual designs for the material. The benefits of FRP are many, but generally it has good strength, good durability while having a low weight. This results in that within bridge construction, it gives the structure a reduced self-weight, which in turn facilitates a variety of things. This thesis shows that FRP materials have advantageous properties and in some situations can be more favorable to use than steel or concrete. However, as previously pointed out, there are no specific Eurocodes for this material. However we are sure that the introduction of a new Eurocode and encouragement from authorities will undoubtedly increase the use of FRP in bridge construction.
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PACK, JULIENNE R. "ENVIRONMENTAL DURABILITY EVALUATION OF EXTERNALLY BONDED COMPOSITES." University of Cincinnati / OhioLINK, 2003. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1046870996.
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El-Zefzafy, Hend. "Evaluation of the environmental effects on the behaviour of GFRP composite tubes for new sustainable building and urban infrastructure applications." Thèse, Université de Sherbrooke, 2013. http://hdl.handle.net/11143/6125.
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The advantages of fiber-reinforced polymer (FRP) composite material have attracted structural and architectural engineers as alternative construction materials of the traditional wood, steel and concrete. Concrete-filled FRP tubes (CFFTs) system is one of the most promising applications of the FRP composit material. This innovative integrated system can protect RC structures from aggressive environmental conditions; sequentially expand the service life of structures. Nevertheless, limited knowledge is available on the CFFT system at extreme service environments. Data related to durability of the CFFT as integrated system comparing with conventional ones is one of the major challenges that need to be addressed. These data are moer required prior to the widespread acceptance and implementation of FRP materials in civil infrastructure. Farther, comprehensive databases in this specific are critical to provide designers and practicing engineers with the knowledge to select the best solution toward achieving a sustainable built environment. This thesis focuses on evaluating the short and long term effect of freze-thaw cycles on the mechanical behavior of the filament wound glass-FRP (GFRP) tubes. In addition, the thesis evaluating the axial performances of reinforced and unreinforced CFFT columns through experimental and theoretical study. To fulfill the objectives of this research, an experimental program has been designed to examine three main parts. (I) Mechanical properties of the GFRP tubes; (II) The axial behavior of CFFT cylinders; (III) The axial behavior of CFFT reinforced and unreinforced columns. The effect of five parameters and their interactions were investigated; namely, the effect of different freze-thaw cycles (in dry air, frsh and/or salt water), number of cycles (100 and/or 300 cycles), two different thicknesses (2.65 mm and 6.4 mm) of the GFRP tube. The influence of using different types of internal longitudinal reinforcement (steel, GFRP, and carbon FRP bars) and the type of transverse reinforcements (spiral steel or FRP tubes) are included in the test variables. Based on the finding of experimental investigation regarding mechanical properties of the GFRP tubes (part I), neither the type nor the number of freze--thaw cycles affect the strength of GFRP tube used in this study. However, increasing in the stiffness, reductions in the strains and transition in failure mechanisms are identified after 300 freze-thaw cycles. The experimental results of axial compression tests on CFFT cylinders (part II) indicated low influence of the freze-thaw cycles on the average ultimate strength of CFFT tube with the large thickness. While, significant and sever degradation was reflected on the behavior of CFFT cylinders with the small thickness after 300 freze-thaw cycles. Based on the experimental test results of (part II) environmental reduction factors were proposed to consider the effect freze/thaw cycles on the strength capacity of CFFT cylinders. Also, the regression analysis was used to predict the service life environmental reduction Factors to design CFFT member for up to 75 years. In addition, an assessment of selected FRP-confined models has been presented to predict the ultimate strength of CFFT cylinders based on the test results of (part I). Finally, comparisons between the experimental results and those predicted by the selected models were presented. The experimental investigation on the performance of reinforced CFFT columns (part III) indicated that the freze-thaw exposure brings about individual degradation, in different levels, in the component of the CFFT (GFRP tube, concrete and reinforcement) as integrated systems. This degradation resulted in reduction in the axial carrying capacities of the conditioned columns. Nevertheless, an increase in compressive strength of the CFFT columns was evident over the RC conventional columns. Based on the test results of this (part III), environmental reduction factors were proposed to account for the effect of freze/thaw cycles on the axial load capacity of reinforced and unreinforced CFFT columns. The data obtained from the test results of (part I), predicted confined compressive strength optained from (part II) and the proposed environmental reduction factors from (part III) were used in the ACI440-2R-08 and CAN/CSA S806-08 design equations to predict the nominal capacity of CFFT columns in sever environmental condition.
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Aoujdad, Khalid. "Caractérisatiοns ultrasοnοres du vieillissement de pales d’hydroliennes et d’éoliennes en milieu marin. : Cοnfrοntatiοn aux essais mécaniques". Electronic Thesis or Diss., Normandie, 2024. http://www.theses.fr/2024NORMLH24.
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Cette thèse porte sur la caractérisation non destructive par ondes ultrasonores des échantillons représentatifs des pales d’éoliennes offshore, avec confrontation aux tests mécaniques. Les échantillons sont en matériaux composites à base de la résine polyester renforcée par des fibres de verre UD GFRP (Unidirectional Glass Fibers Reinforced Polyester). Ils sont soumis à un vieillissement accéléré dans l’eau de mer chauffée à 40 °C et à 60 °C, afin de simuler le milieu marin et réduire la durée d’étude. L’objectif est de trouver des paramètres acoustiques sensibles au vieillissement permettant d’évaluer l’effet du vieillissement ou de le quantifier. L’analyse par ondes guidées de Lamb a montré une diminution des vitesses de phase des modes et de la vitesse de Rayleigh, ainsi que l’augmentation de l’atténuation dans le matériau, ce qui indique que les propriétés mécaniques des matériaux se dégradent à cause du vieillissement. L’imagerie C-scan montre une dégradation de la résine, entraînant la réorganisation des fibres et la modification de leur alignement. Une modélisation numérique par la méthode des éléments finis de la propagation des ondes guidées dans ces matériaux a montré que les propriétés structurelles et géométriques des matériaux se dégradent à cause du vieillissement. Les paramètres les plus attaquées sont les constantes d’élasticité, ainsi que la masse volumique pour des vieillissement plus forts et plus longs. Enfin, le nombre des plis des renforts dans un échantillons joue un rôle important dans sa résistance au vieillissement<br>This thesis discusses the ultrasonic non-destructive characterization of representative samples of offshore wind turbine blades. The samples are made of composite materials based on Unidirectional Glass Fibers Reinforced Polyester (UD GFRP). Samples are subjected to accelerated aging in heated seawater at 40°C and 60°C, in order to simulate the marine environment and reduce study times. The aim is to find acoustic parameters sensitive to aging, enabling the effect of aging to be assessed or quantified. Lamb's guided wave analysis showed a decrease in mode phase velocities and Rayleigh velocity, as well as an increase in attenuation in the material, indicating that the mechanical properties of the material are degrading due to aging. C-scan imaging shows degradation of the resin, leading to reorganization of the fibers and changes in their alignment. Finite element numerical modelling of guided wave propagation in these materials has shown that the structural and geometric properties of the materials degrade with age. The parameters most affected are the elasticity constants, as well as the density for stronger and longer aging. Finally, the number of reinforcement plies in a sample plays an important role in its resistance to aging
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Gurer, Goksu. "Design And Characterization Of Electromagnetic Wave Absorbing Structural Compsites." Master's thesis, METU, 2010. http://etd.lib.metu.edu.tr/upload/12612359/index.pdf.
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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<br>free-space method&rdquo<br>in 18 &ndash<br>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.
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Sonambekar, Abhijit Arvind Soschinske Kurt. "Analysis of GFRP composite tubes for vertical pump application." Diss., Click here for available full-text of this thesis, 2006. http://library.wichita.edu/digitallibrary/etd/2006/t001.pdf.
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Thesis (M.S.)--Wichita State University, Dept. of Mechanical Engineering.<br>"May 2006." Title from PDF title page (viewed on October 2, 2006). Thesis adviser: Kurt Soschinske. Includes bibliographic references (leaves 87-90).
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Ručinskas, Robertas. "Fiber Reinforced Polymer Composite (Frpc) Bridges And Their Construction Perspectives In Lithuania." Master's thesis, Lithuanian Academic Libraries Network (LABT), 2011. http://vddb.laba.lt/obj/LT-eLABa-0001:E.02~2011~D_20110620_141735-19839.
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In this thesis technical and economic analysis of Fiber Reinforced Composite Polymer (FRPC) bridges was performed. Current condition and main issues of conventional bridges in the world and in Lithuania are assessed, main defects are indicated. In this thesis FRPC is considered as an alternative solution for bridge construction. Application range of FRPC for bridge construction is classified and actual bridge examples are analysed. Further, main properties of FRPC are introduced, taking into account influence of material composition, manufacturing technology, long term effects and advantages over conventional materials. Load-deformation, failure behavior analysis of FRPC bridge decks and bridges revealed advantages over conventional bridge solutions and design issues. In addition, existing codes for FRPC bridge design are analysed, design peculiarities are emphasized and current problems are identified. Performed Life Cycle Cost (LCC) analysis revealed financial viability of FRPC bridges. Finally, main conclusions and problems to be solved are stated and FRPC application potential for bridges construction in Lithuania is suggested. Performed analysis revealed that FRPC application for bridges construction is technically and economically viable solution.<br>Šiame magistriniame darbe atlikta Pluoštais Armuotų Polimerinių Kompozitinių (PAPK) tiltų techninė ir ekonominė analizė. Nagrinėjama esama pasaulio ir Lietuvos tiltų būklė, nustatytos būdingos problemos bei defektai. Šiame darbe PAPK yra svarstoma kaip alternativi medžiaga tiltų statybai. Atlikta PAPK panaudojimo klasifikacija tiltų statybai, analizuojami esami PAPK tiltų pavyzdžiai bei jų paplitimas. Toliau nustatomos mechaninės bei fizinės PAPK savybės, atsižvelgiant į medžiagos sandarą, gamybos būdą, ilagalaikius veiksnius ir privalumus lyginant su plienu ir gelžbetoniu. Pagal atliktą PAPK tiltų ir perdangų apkrovos-deformacijų, suirimo analizę nustatyta elementų elgsena, pateiktos pagrindinės problemos bei privalumai palyginus su tradiciniais tiltų sprendiniais. Taip pat išnagrinėtos PAPK tiltų projektavimų normos, pateikti skaičiavimų ypatumai bei problemos. Paskutiniame skyriuje atlikta Gyvavimo Ciklo Kainos analizė parodė PAPK tiltų finansinį įgyvendinamumą. Darbo pabaigoje pateikiamos pagrindinės išvados, rezultatai, spręstinos problemos bei PAPK tiltų panaudojimo rekomendacijos Lietuvoje. Atlikta techninė ir ekonominė analizė parodė, jog PAPK panaudojimas tiltų statybai yra techniškai ir ekonomiškai efektyvus sprendimas.
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Adediran, Oluseun. "Damage assessment of GFRP (glass fibre reinforced polymer) composite beam using vibration data." Thesis, University of Surrey, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.590654.
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Due to increase in the application of glass fibre reinforced polymer (GFRP) beams based structural systems for rehabilitation of existing and construction of new bridges there is a requirement for identification of critical components of these structural systems and the assessment of damage in this sort structural. The application of vibration-based damage detection (VBDD) techniques has been identified as one of the universal technique that is promising in damage assessment in composite beams. The current study aimed at using vibration-based damage detection technique for assessment of damage exhibited by FRP composite beam structure. This thesis addresses the experimental and numerical study of damage assessment of FRP composite beams using vibration data. Dynamic measurements were carried out considering different specified boundary conditions and the effect of supports on the modal parameters and the effect of damage would be obtained. Another set of experiments were conducted on a Fixed-Free beam with unspecified boundary conditions at the free end, where a mass and a spring attached to the free end and beams were tested for different damage scenarios. Triaxial accelerometers were placed at selected locations based on the result of simple FE beam model. The beams were excited in the two (vertical and horizontal) directions by means of a hammer but only the vertical direction was taken into consideration at this point. The responses at different points along the beam were recorded at different levels of damage and fed into an FIT analyzer. Post-processing of data was done with the stochastic subspace identification (SSI) technique. The effect of the damage on the natural frequencies, mode shapes, and damping ratio were determined. Finite element models for the intact, reference and damaged beams were constructed and used to support the dynamic measurements. FE model updating was applied to different five boundary conditions in order to evaiuate their effect. Damage assessment techniques based on selected methods such as modal frequency change, direct mode shapes, change in modal curvature, damage index method and model updating methods were developed and applied to the beams. A unique test configuration was introduced by combining fixed-free beam with undefmed boundary at the free end. The spring and masses were attached to the free-end, this was implemented for different damage scenarios. The outcome of this implement experiment was discussed and analysed.
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Iqbal, Mohammed Asif. "Fatigue Life of Pultruded and Hand Lay-Up GFRP Exposed to Different Environmental Conditions." Fogler Library, University of Maine, 2001. http://www.library.umaine.edu/theses/pdf/IqbalMA2001.pdf.
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Simon, Pavel. "Progresivní styčníky FRP kompozitů konstrukcí dopravní infrastruktury." Doctoral thesis, Vysoké učení technické v Brně. Fakulta stavební, 2018. http://www.nusl.cz/ntk/nusl-390279.
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This thesis deals with junction points of construction used in transport infrastructure, which are made of FRP composite material. Main focus is on bonded joints. The material and geometrical criteria od FRP material and there influence to junctions are analyzed. In sequential steps the development of the design of joints applicable to reference constructions - pedestrian walkways is documented. There are also presented practical experiences from the tests of joints of overlapped and single-sided joints, as well as experience from the design, production and testing of two types of pedestrian bridges on a real scale. Furthermore, extensive comparison of joints, in particular T-joints with closed profiles for selected types of fasteners, is provided. From a simple connection, screws and rivets or plain bonding to combined joints. These are assessed both in terms of bearing capacity and their deformation behavior. These tests are performed for two material combinations, FRP-FRP and FRP-steel.
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Post, Nathan L. "Modeling the Residual Strength Distribution of Structural GFRP Composite Materials Subjected to Constant and Variable Amplitude Tension-Tension Fatigue Loading." Thesis, Virginia Tech, 2005. http://hdl.handle.net/10919/36196.
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One scheme for reliability-based design that is growing in popularity for civil and naval applications is the load and resistance factor design (LRFD). Our goal in this research is the development of a simulation to predict the remaining strength of structural composites subjected to variable fatigue loading and environmental exposure. The results of this simulation can then be used in LRFD to determine appropriate material factors of safety for engineering design applications. The work so far focuses on modeling the response of the material to fatigue damage only. A general phenomenological modeling approach is described and applied in two experimental studies using E-glass/vinyl ester composite materials. Strength distributions are modeled using Weibull statistics and residual strength is modeled using a strength-life equal rank assumption and a Monte-Carlo style simulation.
The model provides good residual strength distribution fits to constant amplitude fatigue data and worked well for ordered block spectrum loading using a 735,641 cycle, 22 stress level spectrum. However, applying a randomized spectrum produced unexpected results with every specimen failing after 200,000 to 400,000 cycles while the model predicts identical residual strength when compared with the block loading case. This work points to a need for focus on developing a better understanding of load order impacts in design of composite structures based on constant amplitude fatigue tests. A future approach toward more detailed micro-mechanics fatigue damage modeling is suggested to enable better modeling of residual strength of laminates subjected to random loading fatigue.<br>Master of Science
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Ospina, Larrea Pedro Manuel. "Analysis of an innovative slim floor composite beam conformed by a custom GFRP pultruded profile and reinforced concrete." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2013. http://amslaurea.unibo.it/6392/.
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GFRP pultruded profiles have shown to be structural profiles with great stiffness, strenght and very low specific weight, making it a great candidate for the rehabilitation of damaged strucutres. To further enhance the strucutral mechanism of these type of beams, the Slimflor composite structural system has lead as basis for this analysis; by replacing the steel beam with a GFRP pultruded profile. To further increase its composite action, a continuous shear connector has been set as part of the beam cross section as well as its needed reinforcement and fire protection.
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Govender, Reuben Ashley. "Characterisation of Glass Fibre Polypropylene and GFPP based Fibre Metal Laminates at high strain rates." Doctoral thesis, University of Cape Town, 2011. http://hdl.handle.net/11427/25150.
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Fibre reinforced polymers (FRP) are finding increasing use in structures subjected to
high rate loading such as blast or impact. Proper design of such structures requires
thorough characterisation of the material behaviour over a range of loading rates from
quasi-static to impact. This thesis investigated the quasi-static and impact response
of Glass Fibre Polypropylene (GFPP) in compression, bending and delamination. The
bending and delamination response of Fibre Metal Laminates (FMLs) based on GFPP
and aluminium was also investigated at quasi-static and impact rates.
High strain rate (5x10^2 to 10^3 /s) compression tests were conducted on GFPP using
a compressive Split Hopkinson Pressure Bar (SHPB) and a Direct Impact Hopkinson
Pressure Bar (DIHPB), in the through-thickness and in-plane directions. In both loading
directions, the peak stress of GFPP increased linearly with the logarithm of strain
rate. For in-plane loading, the failure modes were dominated by localised fibre buckling
and kink bands, leading to delamination. The through thickness loading produced
macroscopic shear and spreading failure modes. However, both of these failure modes
are linked to in-ply fibre failures, due to through thickness compression causing transverse
tensile strain. Previous studies of similar materials have not explicitly stated the
link between through thickness compression and fibre failure associated with transverse
tensile strain.
A novel test rig was developed for Three Point bend testing at impact rates. The
specimen was supported at the outer points on a rigid impacter and accelerated towards
a single output Hopkinson Pressure Bar (HPB), which impacted the specimen
at its midspan. Previous impact bend test rigs based on HPBs were limited to testing
specimens with deflections to failure up to approximately 1mm, whereas the rig implemented
herein measured deflections up to approximately 10 mm. This configuration
permits the output HPB to be chosen purely on the magnitude of the expected impact
force, which resulted in superior force resolution to configurations used in other
studies. The HPB Impact Bend rig was used to test GFPP and aluminium-GFPP FML
specimens, at impact velocities ranging from 5 to 12 m/s. The flexural strength of GFPP
increased with strain rate, while the flexural response of the FML specimens was relatively
insensitive to strain rate.
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Several candidate delamination test geometries were investigated at quasi-static
displacement rates (1 mm/min), and the Single Leg Bend (SLB) test was identified as
suitable for adaptation to higher rate testing. Single Leg Bend delamination tests of
both GFPP and FML specimens were performed using the HPB Impact Bend rig, at
impact velocities of 6 to 8 m=s. The shape of the force displacement response for the
high rate testswas markedly different from the quasi-static tests, for both the GFPP and
FML specimens. Finite element (FE) simulation of the quasi-static and impact rate SLB
tests on GFPP indicated that the difference was probably due to the interaction of flexural
vibrations and stress waves in the specimen and the impacter cross member. The
experimental results and FE analysis suggest that the delamination fracture toughness
of GFPP decreases slightly as strain rate increases. High rate delamination tests on
FML specimens resulted in unstable crack growth.
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Eriksson, Carl-Johan, and Jonas Erlingsson. "FRP i brokonstruktion : -varför används FRP inte i Sverige." Thesis, Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-30284.
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FRP stands for Fiber Reinforced Polymer. FRP materials have yet to be introduced inbridge construction in Sweden. Composite materials can through combined componentsand manufacturing processes be tailored to fit advanced bridge designs. FRP materials arestrong, durable and of low weight. FRP materials give the superstructure reduced weightand are therefore a suitable alternative for industrial prefabrication. This report shows thatFRP materials are possible to use in bridge construction. With the introduction of a specificEurocode we are confident that FRP materials will become a competitive alternative inbridge construction in Sweden in the future.<br>Broar är förenade med stora kostnader, dels för att bygga och dels för att underhålla ochreparera. FRP står för Fiber Reinforced Polymer är ett erkänt material för många andraanvändningsområden, exempelvis flyg och bilindustri. I Europa finns en mängd FRP-broar,men materialet har ännu inte introducerats i någon bro i Sverige.FRP är ett kompositmaterial som genom olika kombinationer av komponenter ochtillverkningsprocesser kan skräddarsys för den aktuella uppgiften i en konstruktion. FRPmaterialär starka, beständiga och har en låg vikt. Fördelar med FRP inom brokonstruktionär att det ger överbyggnaden en minskad egenvikt och därmed är ett lämpligt alternativ attprefabricera industriellt, då bland annat transport- och lyftbarhet gynnas samt att en högbeständighet ger minskat underhåll.Då ingen litteratur hanterar FRP i Brokonstruktion har de intervjuades åsikter varit mycketviktiga för arbetet. Litteraturstudien har legat till grund för en ökad förståelse för egenskaperutmärkande för olika typer av FRP. Intervjuer har utförts med personer som i dagslägetkommit i kontakt med materialet inom brokonstruktion. Detta har gjorts för att nå ett relevantresultat med möjlighet att kunna identifiera materialets för- respektive nackdelar samtanledningen till det låga användandet i Sverige.Rapporten visar att materialet har positiva egenskaper och är möjligt att använda vidkonstruktion av broar. Det saknas i dagsläget en specifik Eurokod som på ett enhetligt sättredovisar hur materialet ska hanteras. Med införandet av en specifik Eurokod och om en nykompetens arbetas fram inom branschen är vi övertygade om att FRP-material kommer attbli ett konkurrenskraftigt alternativ vid brokonstruktion.
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ElGendy, Mohammed. "Punching shear behaviour of slab-column edge connections reinforced with fibre-reinforced polymer (FRP) composite bars." Canadian Society of Civil Engineering, 2014. http://hdl.handle.net/1993/24092.
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The use of fibre reinforced polymer (FRP) composites as an alternate to steel has proved to be an effective solution to the corrosion problem. However, FRP bars have low axial and transverse stiffness compared to steel bars which results in a lower shear capacity of FRP reinforced concrete (RC) elements compared to steel-RC elements.
Flat plate systems are commonly used to take advantages of the absence of beams. They, however, are susceptible to punching shear failure where the column suddenly punches through the slab.
An experimental program was conducted to investigate the punching shear behaviour of slab-column edge connections. Nine isolated full-scale slab-column edge connections were constructed and tested to failure. One connection was reinforced with steel flexural reinforcement, six with GFRP flexural reinforcement and two with GFRP flexural and shear reinforcement. The parameters investigated were the flexural reinforcement type and ratio, the moment-to-shear ratio and the shear reinforcement spacing.
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Almerich, Chulia Ana Isabel. "Diseño, según estados límites, de estructuras de hormigón armado con redondos de fibra de vidrio GFRP." Doctoral thesis, Universitat Politècnica de València, 2011. http://hdl.handle.net/10251/9744.
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Desde la aparición de los redondos de fibra de vidrio como armado del hormigón, las recomendaciones existentes sobre su uso, están en continua revisión al tratarse de un material innovador en el mundo de la ingeniería. Sin embargo, todos los códigos y guías de diseño existentes de elementos de hormigón armado con redondos de GFRP, no consideran en el diseño la resistencia a compresión de los redondos, al no existir métodos de ensayos contrastados, ni resultados homogéneos en los mismos, despreciándose su contribución debido a su bajo módulo de elasticidad, y a consideraciones económicas injustificables.
Esta tesis se centra en definir un método de diseño y cálculo de elementos de hormigón armado con redondos de fibra de vidrio, incluyendo su uso como armadura a compresión, así como su posible resistencia frente al fuego.
La tesis presenta una metodología adecuada a una investigación de los elementos de hormigón armado con este tipo de redondos, basándose principalmente en una amplia base experimental. Se realiza una recopilación bibliográfica y una elaboración de un estado del arte de las aplicaciones de los redondos de FRP como armado del hormigón, y de las directrices existentes en cada uno de los códigos o guías vigentes. Tras ello, se recoge el proceso y los resultados de los trabajos experimentales de los ensayos de tracción, compresión, cortante y adherencia ejecutados a las probetas de fibra de vidrio RTHp, con el fin de obtener de sus características mecánicas, para posteriormente lograr su ratificación por el CSIC, a través del Instituto "Eduardo Torroja", dando pie a la comprobación de su uso como armadura a compresión en elementos de hormigón armado.
Conocido el comportamiento de los redondos, se elabora unas directrices de diseño para elementos de hormigón armado bajo estados limites, cumpliendo con los preceptos marcados por la EHE-08 con respecto a la compatibilidad de tensiones y deformaciones.<br>Almerich Chulia, AI. (2011). Diseño, según estados límites, de estructuras de hormigón armado con redondos de fibra de vidrio GFRP [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/9744<br>Palancia
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Didonè, Marco. "Advanced Non-Destructive Inspections focused on composite materials application for the automotive and marine sectors." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2016.
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The goal of this master thesis is to explain in detail the application of Non-Destructive-Inspection on the Automotive and the Marine sectors. Nowadays, these two particular industries faces many challenges, including increased global competition, the need for higher performance, a reduction in costs and tighter environmental and safety requirements. The materials used for these applications play key roles in overcoming these challenges. So, also an NDI procedure need to be planned in order to avoid problems during the manufacturing process and the after sale life of the structures. The entire thesis work has been done in collaboration with Vetorix Engineering.
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松原, 剛., Go MATSUBARA, 弘泰 西川 та ін. "高強度GFRP積層板の層間はく離疲労き裂進展におよぼす混合モード比の影響". 日本機械学会, 2004. http://hdl.handle.net/2237/9136.
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松原, 剛., Go MATSUBARA, 英夫 尾野, Hideo ONO, 啓介 田中 та Keisuke TANAKA. "高強度GFRPのモードⅠ層間はく離疲労き裂進展におよぼす繊維架橋の影響". 日本機械学会, 2004. http://hdl.handle.net/2237/9138.
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Lagiň, Juraj. "Řešení vybraných detailů betonových konstrukcí s využitím FRP výztuže." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2020. http://www.nusl.cz/ntk/nusl-409796.
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The diploma thesis is devided into two levels. The Primary part of the thesis is the theoretical part, which is part of project „FV10588 – New generation of spatial prefab made from high-firm concrete with increased mechanical resistence and endurance“, realized in cooperation with Faculty of Civil Engineering at VUT university – Institute of concrete and masonry structures. The project deals with frame corners in the form of steel and composite reinforcement which will compared through experiments and various kind of calculate proceedings. The secondary part of thesis focuses on the static-design project of cooling reservoir, placed under the ground, while is stressed by temperature. The reinforcement of the construction is realized in two ways – steel and composite reinforcement with their effectivity compared.
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Yaqub, Muhammad. "Axial compressive and seismic shear performance of post-heated columns repaired with composite materials." Thesis, University of Manchester, 2010. https://www.research.manchester.ac.uk/portal/en/theses/axial-compressive-and-seismic-shear-performance-of-postheated-columns-repaired-with-composite-materials(76babab7-06db-49b2-a8be-e76c17495eaa).html.
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In the light of extreme events of natural disasters (earthquakes or hurricanes) and accidents (fire or explosion), repairing and strengthening of existing concrete structures has become more common during the last decade due to the increasing knowledge and confidence in the use of composite advanced repairing materials. The past experience from real fires shows that it is exceptional for a concrete building to collapse as a result of fire and most fire-damaged concrete structures can be repaired economically rather than completely replacing or demolishing them. In this connection an experimental study was conducted to investigate the effectiveness of fibre reinforced polymer jackets for axial compressive and seismic shear performance of post-heated columns. This study also investigates the effectiveness of ferrocement laminate for the repairing of post-heated reinforced concrete columns.A total of thirty-five reinforced concrete columns were constructed and then tested after categorising them into three main groups: un-heated, post-heated and post-heated repaired. The post-heated columns were initially damaged by heating (to a uniform temperature of 500°C). The concrete cubes were also heated to various temperatures to develop the relation between compressive strength and ultrasonic pulse velocity. The residual compressive strength of the concrete cubes and reinforced concrete columns were determined by ultrasonic testing. The post-heated columns were subsequently repaired with unidirectional glass or carbon fibre reinforced polymer and ferrocement jackets. The experimental programme was divided into two parts. The columns of experimental part-1 were tested under axial compressive loading. The columns of experimental part-2 with a shear span to depth ratio of 2.5 were tested under constant axial and reversed lateral cyclic loading. The results indicated that the trend of reduction in ultrasonic pulse velocity values and in residual compressive strength of concrete was similar with increasing temperature. The reduction in residual stiffness of both post-heated square and circular columns was greater than the reduction in ultimate load. The circular sections benefited more compared to the square cross-sections with fibre reinforced polymers for improving the performance of post-heated columns in terms of compressive strength and ductility tested under axial compression. GFRP and CFRP jackets performed in an excellent way for increasing the shear capacity, lateral strength, ductility, energy dissipation and slowed the rate of strength and stiffness degradation of fire damaged reinforced concrete square and circular columns tested under combined constant axial and reversed lateral cycle loading. However, the effect of a single layer of glass or carbon fibre reinforced polymer on the axial stiffness of post-heated square and circular columns was negligible. The use of a ferrocement jacket for the repairing of post-heated square and circular columns enhanced the axial stiffness and ultimate load carrying capacity of columns significantly.
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松原, 剛., Go MATSUBARA, 啓介 田中 та Keisuke TANAKA. "高強度GFRPのモードⅢ層間はく離疲労き裂進展におよぼす応力比の影響". 日本機械学会, 2006. http://hdl.handle.net/2237/9127.
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松原, 剛., Go MATSUBARA, 英夫 尾野, Hideo ONO, 啓介 田中 та Keisuke TANAKA. "高強度GFRPのモードⅡ層間はく離疲労き裂進展におよぼす応力比の影響". 日本機械学会, 2004. http://hdl.handle.net/2237/9159.
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Sabathier, Thibault. "De la compréhension des mécanismes de dégradation d'un renfort composite en milieu cimentaire à l'amélioration de ses propriétés mécaniques." Thesis, Montpellier, 2020. http://www.theses.fr/2020MONTS059.
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Les fibres de verre, lorsqu’elles sont utilisées en tant que renfort dans des milieux cimentaires, sont sujettes à une perte progressive de leurs propriétés mécaniques. Ces pertes ont été pour la première fois mises en évidence dans les années 60. Depuis, de nombreuses études ont cherché à limiter ces pertes de propriétés, principalement par des modifications de formulation des ensimages.Cette étude se focalise d’abord sur la compréhension des phénomènes entrainant la perte des propriétés mécaniques du renfort développé par Chomarat. Pour cela, l’étude du vieillissement des différents composants de la grille composite ont montré que les phénomènes de corrosion de la fibre et de précipitation de cristaux, responsables de la perte des propriétés mécaniques des premiers renforts cimentaires, sont largement prévenus par les ensimages formulés aujourd’hui. Les analyses microscopiques et tests de traction mécanique sur filament montrent que la perte des propriétés mécaniques est majoritairement pilotée par la présence d’eau au contact de défauts de surface de la fibre de verre. La diffusion de l’eau au travers du revêtement a donc un rôle prédominant dans la dégradation de la grille.Pour limiter les conséquences de ce phénomène, une démarche d’amélioration du renfort est mise en place afin de réduire l’accessibilité de l’eau à la surface de la fibre. L’étude montre que l’imprégnation de la fibre par des tensioactifs permet de limiter fortement les pertes des propriétés mécaniques.Une partie du travail de thèse consiste également à développer des tests permettant une évaluation efficace de la perte des propriétés du produit final en s’appuyant notamment sur la mesure de la diffusion de l’eau au travers du revêtement. De plus, afin de répondre aux cahiers des charges en perpétuelle évolution, le développement d’un nouveau test de rétention des propriétés mécaniques de la grille, plus simple et rapide, est également développé<br>The glass fibers, when they are used as reinforcement materials in cementitious media, undergo a progressive loss of their mechanical properties. These losses were observed for the first time during the 1960s. Since then, a lot of studies aimed to limit these losses, mainly through the modifications of the sizing formulations.This study focuses on the understanding of the phenomena leading to the decrease of the mechanical properties of the reinforcement material developed by Chomarat. Thus, the ageing study of the composite scrim components shows that the corrosion phenomenon and the crystal formation phenomenon, which were both responsible for the mechanical losses observed on the first cementitious reinforcement, are mainly prevented by the sizing formulations.The microscopic analysis and the filament tensile strength test show that the mechanical properties drop is mainly driven by the water presence on contact with the glass fiber surface flaws. The water diffusion through the coating has a decisive role in the scrim degradation.To limit the diffusion phenomenon consequences, we have set up an approach to reduce the accessibility of the water to the fiber surface. The study shows that the impregnation of the fibers by surfactants allows to strongly limit the mechanical property losses.A part of the work consists to develop new tests allowing an efficient evaluation of the scrim property losses by the measure of the water diffusion through the coating. Moreover, to answer to the perpetual evolution specifications, the development of a new scrim mechanical property test, easier and faster, is presented
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松原, 剛., Go MATSUBARA, 啓介 田中 та Keisuke TANAKA. "高強度GFRP積層板における内部欠陥からの層間き裂と貫通層間き裂の疲労進展特性の関係". 日本機械学会, 2006. http://hdl.handle.net/2237/9125.
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Elmushyakhi, Abraham. "In-Plane Fatigue Characterization of Core Joints in Sandwich Composite Structures." University of Dayton / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1510678155755824.
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Azzarone, Davide. "Sviluppo di sistemi di serraggio di un pacco batterie per applicazioni automotive." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2021.
Find full textAbstract:
La tesi si colloca all’interno del progetto LiBER, il cui obiettivo è realizzare un pacco batterie leggero e modulare.
Lo scopo di questo elaborato è la progettazione di un sistema di serraggio radiale per garantire il bloccaggio tra i componenti interni del pacco batteria e il case esterno.
Dopo aver definito i componenti del sistema, si è proceduto con un’analisi dettagliata dei prodotti presenti sul mercato, per identificare le caratteristiche tecniche da ottimizzare, e realizzare un prodotto competitivo.
Al termine dell’analisi si sono stilate le specifiche di progetto, seguendo le normative e i test da effettuare per ottenere l’omologazione europea.
Identificate le specifiche, si procede con la formulazione di un modello analitico, i cui dati mancanti, come le rigidezze dei componenti o le caratteristiche dei materiali utilizzati, sono stati calcolati o ottenuti mediante test in laboratorio.
Terminata la fase di comprensione del problema, si procede con lo sviluppo di varie soluzioni mediante software CAD e alla successiva analisi FEM, opportunamente settata per simulare correttamente le complessità introdotte dall’uso del materiale composito.
La validazione delle soluzioni proposte è stata effettuata tramite test di serraggio in pressa di un modello ridotto e, conseguentemente, si è estesa l’analisi al modello in scala 1:1, con case laminato in GFRP.
Ottenuta la validazione del sistema, si esplora la possibilità di poter utilizzare il sistema di serraggio proposto a seguito di una variazione di tecnologia di fabbricazione del case esterno, passando dalla produzione per pultrusione, al fine di abbattere i costi di produzione di due ordini di grandezza.
Terminato lo sviluppo modello, si conclude l’elaborato con la progettazione della struttura necessaria per l’assemblaggio dei componenti sviluppati.
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Miotto, José Luiz. "Estruturas mistas de madeira-concreto: avaliação das vigas de madeira laminada colada reforçadas com fibras de vidro." Universidade de São Paulo, 2009. http://www.teses.usp.br/teses/disponiveis/18/18134/tde-15062009-094616/.
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No cenário da produção de edificações sustentáveis, a madeira laminada colada (MLC) ocupa lugar de destaque, sobretudo pela possibilidade de emprego de madeiras provenientes de florestas plantadas. Com o propósito de amenizar os problemas de durabilidade, quando exposta às intempéries, uma solução pressupõe a associação das vigas de MLC com um tabuleiro de concreto armado, sendo as partes ligadas por meio de conexões flexíveis. Essa técnica tem sido aplicada com sucesso, especialmente por conta do expressivo acréscimo de rigidez proporcionado pela composição. No entanto, em situações de elevados carregamentos ou de grandes vãos, a aplicação de reforços com fibras sintéticas, na face tracionada das vigas de MLC, aprimora ainda mais essa técnica, refletindo-se em significativos acréscimos nas forças de ruptura. Neste trabalho avaliou-se, de forma experimental e numérica, o comportamento estrutural de vigas mistas de MLC-concreto reforçadas com fibras de vidro. Numa primeira etapa foram estudados os elementos de ligação, optando-se pelos ganchos de aço com diâmetro de 8 mm pelo seu excepcional desempenho. Em seguida foram confeccionadas as vigas mistas, com e sem reforços com fibras de vidro, registrando-se acréscimo médio de 37% no módulo de ruptura (MOR) das vigas mistas em relação às vigas de MLC, ambas reforçadas com fibras. O emprego do reforço com fibras sintéticas se justifica pela diminuição na dispersão dos resultados. Por fim, um algoritmo foi proposto para o dimensionamento das vigas mistas de MLC-concreto reforçadas com fibras de vidro, o qual, associado às avaliações numéricas e experimentais, permite ampliar os horizontes de aplicação das estruturas de madeira.<br>Production of sustainable constructions forms a scenario where glulam beams occupy a prominence place, because of the possibility of utilization of wood that comes from planted forests. With the intention of diminution in the durability problems, when exposed to the weather effects, a solution presupposes the association of glulam beams with a reinforced concrete slab, in which the components are linked by means of flexible connections. This technique has been applied with results, especially due to the expressive increment in stiffness provided by the composition. However, in situations where high loads or great spans are found, the application of synthetic fibers reinforcements in the tension side of glulam beams improve this technique, being reflected in significant increments in the rupture forces. In this study it was evaluated, in experimental and numerical way, the structural behavior of glulam-concrete composite beams reinforced with glass fiber reinforced polymer (GFRP). In a first stage the connection elements were studied, being opted for steel hooks with 8 mm in diameter because of their exceptional behavior. Soon after, the composite beams were made with and without GFRP reinforcements and their tests showed average increment of 37% in modulus of rupture (MOR), when the composite beams were compared to glulam beams, both reinforced with GFRP. The decrease in the variability of results justifies the use of synthetic fibers reinforcements. Finally, an algorithm was proposed for the design of glulam-concrete composite beams reinforced with GFRP. So, when associated with the experimental and numerical evaluations that were carried out, this method allows enlarging the horizons of timber structures applications.
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Kumar, Krishna. "Experimental Study on Drilling of GFRP and CFRP Composites." Thesis, 2017. http://ethesis.nitrkl.ac.in/9011/1/2017_MT_KrKumar.pdf.
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Glass fiber reinforced plastic (GFRP) and Carbon fiber reinforced plastic (CFRP) are widely used composites in the area of manufacturing industry. Drilling of such composites for assembling is increasing fast with the increase in demand for such composites materials. The high specific strength and fatigue characteristics of such composites make these superior as compared to conventional material. Several damages like uncut fibers, delamination, edge chipping fiber pull out, and occur during drilling. Delamination is the major problem during drilling of CFRP and GFRP as it causes poor assembly tolerance, reduced structural integrity and deteriorated long term performance. Machining of composites is performed at various drilling parameters using CNC machine. In order to reduce number of experimental runs, a face centred central composite design (FCCCD) is used considering feed rate, spindle speed, and drill size as three drilling parameters. Delamination factor of CFRP and GFRP under each experimental run is estimated. It has been observed that delamination is related to the thrust force. The thrust force of step drill and through hole drill under different drilling parameter setting during drilling of CFRP and GFRP is experimentally obtained using drill dynamometer. It has been found that step drilling is superior to through hole drilling since it reduces thrust force and consequently delamination.
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Mhetre, Yogesh Shamsundar. "Mechanical Performance Evaluation of Woven and Unidirectional GFRP Composite Through Numerical Simulation." Thesis, 2017. http://ethesis.nitrkl.ac.in/9033/1/2017_MT_YSMhetre.pdf.
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In this research work, detail investigation on mechanical response of woven as well as unidirectional Glass fiber reinforced polymer (GFRP) composite has been performed using finite element analysis (FEA). Representative volume element (RVE) model of GFRP composite has been undergone different simulated mechanical tests such as tensile test by applying 160N load, three-point bending test by employing 160N against two fixed supports, cyclic loading from 0 to 160N, in-situ test at 120oC temperature, and free vibrational analysis to evaluate natural frequencies. Inter-laminar shear strength (ILSS) of woven GFRP composite has been observed by conducting Short beam shear (SBS) test. To investigate adhesive strength of unidirectional and woven GFRP composite, Peel-off test has been performed. Total deformation, equivalent stress and equivalent elastic strain are evaluated though numerical simulation using finite element method. It is observed that the total deformation obtained is more uniform in unidirectional structure composite compared to woven structure composite due to interlocking behavior of fibers in woven composite structure. It is also found that the equivalent stress value is higher in tension than three-point bending for both types of composites. The equivalent stress value is higher in case of woven GFRP composite as compared with unidirectional GFRP composite in three-point bending test. According to simulated in-situ test, maximum stress value decreases as temperature increases in unidirectional GFRP composite whereas, in woven GFRP composite variation in maximum stress value is negligible. Delamination failure of material after conducting SBS test is observed at time 45 sec for displacement 0.15mm. Material failure has been occurred at maximum load 160.512 N and the same value is assumed to calculate ILSS. By performing Peel-off test, it has been concluded that unidirectional GFRP composite structure has very low adhesive strength as compared to woven GFRP composite structure.
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Mohanty, Sarat Chandra. "Development of CNT Modified GFRP Composite and Assessment of Its Elevated Temperature Mechanical Performance." Thesis, 2016. http://ethesis.nitrkl.ac.in/9079/1/2016_MT_214MM1340_SCMohanty.pdf.
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Matrix modification in fiber reinforced polymer (FRP) composite by a scientifically structured nano-filler is a current trend of research which has been globally acknowledged to enhance the transverse mechanical performance of the FRP composites. In the present investigation, modification of epoxy resin has been done by multi-walled carbon nanotube (MWCNT) by a sequential process comprising of stirring, sonication followed by vacuum degassing (VD). The potential improvement due to MWCNT modification in the polymer matrix lies in the efficient dispersion of MWCNT in the epoxy matrix with introduction of least possible defects in the final material. Hence, initially emphasis has been focused on the effect of varying the VD time (4, 12, 18 and 50 hours) of MWCNT/epoxy mixture. After optimising the VD time, effect of MWCNT content (0.1 and 0.3 wt. %) in the epoxy resin on flexural properties of MWCNT embedded glass/epoxy-composite (MWCNT-GE) with respect to the control glass/epoxy (GE) composites were evaluated. The flexural test results revealed that maximum strength in the MWCNT (0.1%)-GE composite was obtained with a vacuum degassing time of 18 hours, which was about 27% higher than the control GE sample. In the next phase of the work, emphasis has been focused on elevated temperature durability of MWCNT/GE, functionalized CNT modified FRP composite and control GE composite. In-situ 3-point bend tests were carried out for control GE, 0.1wt% pristine CNT embedded GE (CNT/GE) and 0.1wt% COOH functionalized CNT embedded GE (FCNT/GE) at room temperature (25°C), 70°C, 90°C and 110°C. It has been observed that addition of 0.1% CNT in polymer matrix enhances the flexural strength and flexural modulus by 22.22% and by 7.24% respectively than control GE composite at room temperature whereas addition of 0.1% FCNT enhances flexural strength and flexural modulus by 40.21% and 15.05% respectively than control GE composite. Post failure fractured surface was analysed by SEM to study different fracture mechanism.
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Ηλιόπουλος, Ηλίας. "Numerical simulation of damage progression in GFRP composites under cyclic loading." Thesis, 2013. http://hdl.handle.net/10889/7285.
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Αντικείμενο της εργασίας αποτελεί η ανάπτυξη ανισότροπου μη γραμμικού καταστατικού μοντέλου υλικού, που περιλαμβάνει την πρόβλεψη της έναρξης και προοδευτικής διάδοσης της βλάβης, για την προσομοίωση της μηχανικής συμπεριφοράς πολύστρωτων διατάξεων από ινώδη σύνθετα υλικά υπό κυκλική φόρτιση. Το καταστατικό μοντέλο χρησιμοποιεί ως δεδομένα εισόδου τη μηχανική συμπεριφορά της στρώσης υπό κυκλική εντατική κατάσταση σταθερού εύρους και προβλέπει τη διάρκεια ζωής και την εναπομένουσα δυσκαμψία και στατική αντοχή οποιασδήποτε πολύστρωτης διάταξης υπό πολυαξονική κυκλική φόρτιση μεταβλητού εύρους.
Στο πλαίσιο της εργασίας διεξήχθησαν πειράματα για την ανάπτυξη καταστατικών μοντέλων που περιγράφουν την μηχανική συμπεριφορά της στρώσης υπό κυκλική φόρτιση, στις κύριες διευθύνσεις της, επεξεργάστηκαν πειραματικά δεδομένα, παρήχθησαν τα καταστατικά μοντέλα και αναπτύχθηκε κώδικας για την προσομοίωση.
Τα μοντέλα της μηχανικής συμπεριφοράς της στρώσης υπό κυκλική εντατική κατάσταση παρουσιάστηκαν λεπτομερώς, όπως προέκυψαν από την επεξεργασία δεδομένων από 304 πειράματα, στατικά και κοπωτικά.
Εισήχθησαν νέα καταστατικά μοντέλα για την αναπαράσταση της μηχανικής συμπεριφοράς της στρώσης υπό κυκλική φόρτιση, για τις ιδιότητες που δεν υπήρχαν διαθέσιμα ή που τα διαθέσιμα κρίθηκαν μη ικανοποιητικά.
Η μέθοδος είχε δύο εφαρμογές. Στην μία θεωρήθηκε ομογενές εντατικό πεδίο και ο υπολογισμός της εντατικής κατάστασης έγινε με τις υποθέσεις της κλασικής θεωρίας πολύστρωτων πλακών. Η άλλη ήταν σε εμπορικό κώδικα πεπερασμένων στοιχείων.
Διεξήχθη εκτενής ποιοτική ανάλυση ευαισθησίας της μεθόδου για να διαπιστωθεί ποιοί παράγοντες επηρεάζουν περισσότερο τα αποτελέσματα.
Η εγκυρότητα της μεθόδου επιβεβαιώθηκε από ιδιαίτερα εκτενή σύγκριση των προβλέψεων και των δύο εφαρμογών της με πειραματικά δεδομένα: 785 πειράματα διαφόρων πολύστρωτων διατάξεων υπό διάφορες συνθήκες φόρτισης.<br>An anisotropic non-linear constitutive model implementing progressive damage concepts to predict the residual strength/stiffness and life of composite laminates subjected to multi-axial variable amplitude cyclic loading, FADAS, was presented. The in-plane mechanical behaviour in the principal directions of the uni-directional ply under cyclic loading was also comprehensively presented and implemented in the constitutive model. Stiffness degradation and static or fatigue strength of any multi-directional stacking sequence can be predicted.
Two implementations of the method were developed. In the first, homogenous stress field was considered and the cyclic load sequence was simulated cycle by cycle. The second was in a commercial FE code. Strength and stiffness degradation were modelled using simple and cost-effective schemes, while the failure criterion of Puck along with post-failure behaviour of the material, were implemented.
An extensive qualitative sensitivity analysis was performed to determine the factors affecting more the simulation results. The method was exhaustively validated by almost entirely reclaiming a huge experimental database, consisting of various laminates under various loading conditions.
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Sahu, S. "Strengthening reinforced concrete beams using Glass Fiber Reinforced Polymer (GFRP) composites." Thesis, 2014. http://ethesis.nitrkl.ac.in/5943/1/E-110.pdf.
Full textAbstract:
Deterioration in reinforced concrete structures is a major issue faced by the infrastructures and bridge industries all over the world. One of the suitable solutions is to modify and to improve the performance of the structure by introducing a new technique called “Strengthening”. It is not only cost effective but also helps in improving the service life of structures. To strengthen deficient RC structures, previously steel plates was used as external reinforcement but in last fifteen years, FRP plates have been used to replace steel because of their superior properties. The present study describes the flexural and shear strengthening of rectangular RC beams using glass fiber reinforced polymer (GFRP). In total, 12 no. of beams were cast and divided into 2 groups varying in steel reinforcement. One beam in each group, designated as control beam. Rest beams were strengthened in different orientations using GFRP sheets. Anchorage plate has been used to prevent premature debonding failure. The beams were tested under symmetrical four-point static loading system. A theoretical comparison was done to support the experimental results.
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Prusty, Rajesh Kumar. "Implication of CNT Fillers on Environmental Durability of GFRP Composites: An Evaluation of Microstructural Features and Mechanical Properties." Thesis, 2017. http://ethesis.nitrkl.ac.in/9365/1/2017_PhD_RKPrusty_513MM4084.pdf.
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The excellent mechanical performance of the fiber reinforced polymer (FRP) composites in combination with its low density and corrosion resistance has made it a revolutionary material in the current structural world. However, the poor out of plane properties of these laminated FRP composites creates an interest for suitable modification of the matrix and/or interface by scientifically structured nanofillers. The paucity of structural defects in carbon nanotube (CNT) with unrivalled mechanical properties has always posed an interest to material scientists for its potential incorporation in soft polymer resins to achieve superior mechanical stability. But, the performance of these CNT modified FRP composites under various in-service environments must be well ensured before accepting these materials for different high end applications.
Present study starts with assessing the flexural behaviour of control glass fiber/epoxy (GE) and 0.3% multi-walled CNT (MWCNT) embedded GE (CNT-GE) composites at different in-service environmental temperatures. In-situ 3-point bend tests were performed on GE and CNT-GE composites at -80, -40, 20, 70 and 110 °C temperatures. The results revealed that at 110 °C temperature, the flexural strength of GE and CNT-GE composites was significantly decreased by 67% and 81% respectively in comparison to their strength at -80 °C temperature. Dynamic mechanical thermal analysis (DMTA) was carried out in the temperature range of -100 °C to 200 °C to correlate the mechanical and thermo-mechanical response of both the material systems. Addition of 0.3 wt. % MWCNT in GE composite resulted in lowering of glass transition temperature (Tg) by 12°C.
Further, emphasis was given on the elevated temperature durability of GE composites with various MWCNT contents (0, 0.1, 0.3 and 0.5 wt.% of epoxy). Flexural testing at room temperature revealed that addition of 0.1% MWCNT yielded maximum strength (+32.8% over control GE) and modulus (+11.5% over control GE) amongst all the composite systems. Further, all the CNT-GE composites resulted in accelerated degradation of mechanical performance with increasing temperature as compared to GE composite. 0.1% CNT-GE composite, which exhibited highest strength at room temperature, exhibited the poorest flexural performance at 110 °C. Fractographic analysis figured out various failure modes in all composites at various temperatures.
To evaluate the susceptibility of CNT-GE composites towards cryogenic shock, alteration in the flexural performance of GE composites with and without MWCNT was studied after liquid nitrogen conditioning for various time intervals. Decrease in strength and modulus was observed for short time span of liquid nitrogen conditioning and the rate of this decrement was higher for the CNT-GE composites. On the other hand, a longer conditioning time enhances the strength of CNT-GE composites more effectively than GE composite due to generation of clamping stress at CNT/epoxy interface.
The next objective is aimed to elucidate the temperature dependant reinforcement efficiency due to the chemical restructuring of the nano-filler/matrix interphase in CNT embedded GE composites. Carboxyl functionalized CNT embedded GE (FCNT-GE) composite exhibits 25% and 10% better strength than GE and unmodified (pristine) CNT embedded GE (UCNT-GE) composites respectively, at room temperature. Covalently bonded CNT/epoxy interface in oxidized nanotube modified epoxy matrix restricts the interfacial debonding to a better extent than pristine one upon excursion to elevated temperatures. On the contrary, mechanical gripping at the CNT/epoxy interface at lower temperatures maximizes its failure strength, resulting in an admirable structural material for low and cryogenic temperature applications. Thermo-mechanical properties and microscopic evidences of the interfaces at nanoscale (CNT/epoxy) and microscale (glass/epoxy) divulge the synergetic strengthening effect due to both chemical functionalization and low temperature environment.
The effect of diffusion temperature on the water uptake and subsequent degradation behaviour of GE and CNT-GE composite has also been studied. Presence of CNT in the GE composite significantly suppressed its water absorption propensity at lower temperature (25°C). It is attributed to the reduced free volume of polymer and hydrophobic nature of the CNTs, which forces the water molecules to follow a torturous extended path. However, CNT reinforcement in GE composite adversely affects its high temperature water resistance due to generation of unfavourable thermal and hygroscopic stresses at the CNT/polymer interfaces. Flexural testing of the water saturated samples revealed that diffused water exerts more detrimental effect on mechanical performance of CNT-GE composite than control GE composite. The extent of recovery in mechanical performance of the composites has also been evaluated after complete desorption of the water saturated samples.
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Twu, C. M., and 涂嘉明. "Damage Analysis of GFRP Composites Subject to a Low-Velocity Drop Impact Loading." Thesis, 2001. http://ndltd.ncl.edu.tw/handle/23685752918754397326.
Full textAbstract:
碩士<br>國立成功大學<br>航空太空工程學系<br>89<br>The purpose of this thesis is to study the force and energy curve of composites due to low-velocity impact, and simulate the all curves with a numerical analysis method, then compare the experimental result and the numerical simulation. There are two types of GFRP composites: Plain weaved and Double-wall GFRP composites and two types of automotive application based composites in this thesis. We do a series of low-velocity impact experiment utilizing the Drop-Weight Tower Tester, and analyze the experimental data. We can understand the condition of damage and energy absorbed of the specimen from the experimental curve to be the basis of the choice of the materials and the assessment of the ability of impact resistance.
In this thesis, we use the“Maxwell Model Method”to simulate the whole behavior during low-velocity impact, such as local indentation and global bending deformation. The model separate the predicted energy from elastic stored, dissipated, and damage propagation. Finally, we compare the experimental data and numerical simulation; there is a good resultant for the low-velocity impact testing.
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Verma, Rajesh Kumar. "Fuzzy rule based optimization in machining of glass fiber reinforced polymer (GFRP) composites." Thesis, 2012. http://ethesis.nitrkl.ac.in/3971/1/209ME2209_RAJESH_KUMAR_VERMA_(Production_Engineering).pdf.
Full textAbstract:
With the increasing use of Fiber Reinforced Polymer (FRP) composites outside the defense, space and aerospace industries; machining of these materials is gradually assuming a significant role. The current knowledge of machining FRP composites is in transition phase for its optimum economic utilization in various fields of applications. Therefore, material properties and theoretical mechanics have become the predominant research areas in this field. With increasing applications, economical techniques of production are indeed very important to achieve fully automated large-scale manufacturing cycles. Although FRP composites are usually molded, for obtaining close fits and tolerances and also achieving near-net shape, certain amount of machining has to be carried out. Due to their anisotropy, and non-homogeneity, FRP composites face considerable problems in machining like fibre pull-out, delamination, burning, etc. There is a remarkable difference between the machining of conventional metals and their alloys and that of composite materials. Further, each composite differs in its machining behavior since its physical and mechanical properties depend largely on the type of fibre, the fibre content, the fibre orientation and variabilities in the matrix material. Considerable amount of literature is readily available on the machinability of conventional metals/alloys and also polymers to some extent; with very limited work on FRP composites. Therefore, machining process optimization for all types FRP composites is still an emerging area of research. In this context, the present research highlights a multi-objective extended optimization methodology to be applied in machining FRP-polyester/epoxy composites with contradicting requirements of quality as well as productivity. Attempt has been made to develop a robust methodology for multi-response optimization in FRP composite machining 6 for continuous quality improvement and off-line quality control. Design of Experiment(DOE) has been be selected based on Taguchi’s orthogonal array design with varying process control parameters like: spindle speed, feed rate and depth of cut. Multiple surface roughness parameters of the machined FRP product along with Material Removal Rate (MRR) of the machining process have been optimized simultaneously. A Fuzzy Inference System (FIS) integrated with Taguchi’s philosophy has been proposed for providing feasible means for meaningful aggregation of multiple objective functions into an equivalent single performance index (MPCI). This Multi Performance Characteristic Index (MPCI) has been optimized finally. Detailed methodology of the proposed fuzzy based optimization approach has been illustrated in this reporting and validated by experiments.
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Sonkar, V. "Multi-objective optimization in machining of GFRP and MMC composites: two case experimental research." Thesis, 2014. http://ethesis.nitrkl.ac.in/6296/1/E-70.pdf.
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Composite materials like GFRP and MMCs having more importance in various manufacturing industries mainly in aerospace and automotive industries and many engineering application, because of their unique mechanical properties as compare to the conventional material. Drilling is the most common machining process in manufacturing industries for assembly of components but drilling of composite may possesses many difficulties such as fiber pull out, delamination and circularity etc. which affects the quality of drilled hole. To overcome these difficulties the effect of machining parameters on different machining responses should be investigated for attaining high product quality as well as satisfactory machining process performance. Therefore, the main objective of this dissertation is to investigate the various machining performance characteristics with different machining condition in drilling of GFRP and MMCs composites by using various integrated multi objective optimization methodologies. In this presented thesis, Deng’s similarity method integrated with Taguchi, TOPSIS integrated with Taguchi method (in drilling of GFRP composite) and PCA-Grey method integrated with Taguchi, Grey-TOPSIS Integrated with Taguchi method (in drilling of MMCs), have been implemented for obtaining the optimal machining conditions.
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Singh, Abhishek. "Drilling of Glass Fiber Reinforced Polymer (GFRP) Composites: Parametric Appraisal and Multi Response Optimization." Thesis, 2015. http://ethesis.nitrkl.ac.in/6796/1/DRILLING_Singh_2015.pdf.
Full textAbstract:
In today’s scenario, composite like Glass Fiber Reinforced Polymer (GFRP) is a standout amongst the most alluring and profitable material among all the designing materials. The reason for using these composite laminates is their superior properties and their influential application in aerospace industries, aircraft structural components, and others. The present learning about machining of GFRP composites is in a moving stage for its ideal usage in different fields of uses in the monetary perspective. Hence, the hypothetical mechanics have ended up overwhelming in this field to attain to completely mechanized substantial scale assembling cycles. Composites fluctuate in their machining direct as a consequence of their mechanical and physical properties that basically depend on upon the kind of fiber, content of fiber, alignment of fiber, and inconsistency in the matrix material. The very common operation for the assembly of components made up of GFRP is using rivets and joints. To join components by rivets and joints the basic requirements is good quality holes, for which drilling operation is performed. Drilling of GFRP by the conventional methods is a complicated machining process, to achieve good quality hole, as glass fibers are used in the material. Likewise, composite overlays are viewed as difficult to machine materials. Drilling process is highly depended on the cutting parameters (i.e. Feed, Speed, and Drill Diameter), tool geometry, instrument and workpiece material, delamination along with torque and thrust force. Optimization is done to get the nominal measures for all parameters. The drilling parameters like spindle speed and feed rate are improved by considering various performance qualities, such as surface roughness of the workpiece, delamination occurred while drill along with thrust force. Understanding the machining behavior of the work-piece results in vi least waste and defects. To evaluate thrust force and torque, motionless and active analysis of the work-piece is done. Multi-response optimization is termed as a process of opting the best suitable alternative among all the options available. Optimization of machining parameters is done to improve the product quality, as well as its productivity. In this perspective, an attempt has been made to develop a vigorous approach for the optimization of multiple responses in GFRP composite drilling. For persistent quality change and logged off quality control, strategy of experimentation has been chosen in light of Taguchi’s orthogonal configuration along with shifting procedure control constraints like, spindle speed, feed and drill diameter. A utility concept incorporated with Taguchi’s reasoning has been proposed for giving possible intends to the important accumulation of more than one objective functions into an equal single execution index.
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Shit, Trishanu. "Experimental and numerical study on behavior of externally bonded RC T-beams using GFRP composites." Thesis, 2011. http://ethesis.nitrkl.ac.in/2913/1/trishanu_thesis.pdf.
Full textAbstract:
Fiber-reinforced polymer (FRP) application is a very effective way to repair and strengthen structures that have become structurally weak over their life span. FRP repair systems provide an economically viable alternative to traditional repair systems and materials. In this study experimental investigation on the flexural behavior of RC T-beams strengthened using glass fiber reinforced polymer (GFRP) sheets are carried out.
Reinforced concrete T beams externally bonded with GFRP sheets were tested to failure using a symmetrical two point static loading system. Seven RC T-beams were casted for this experimental test. All of them were weak in flexure and were having same reinforcement detailing. One beam was used as a control beam and six beams were strengthened using different configurations of glass fiber reinforced polymer (GFRP) sheets. Experimental data on load, deflection and failure modes of each of the beams were obtained. The effect of different amount and configuration of GFRP on ultimate load carrying capacity and failure mode of the beams were investigated.
The experimental results show that externally bonded GFRP can increase the flexural capacity of the beam significantly. In addition the results indicated that the most effective configuration was the U-wrap GFRP .A series of comparative studies on deflection between the present experimental data and results from finite element method and IS code method were made. Future area of research are being outlined.
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Mahananda, Ranjan. "Optimization of Machining Performance Yields during Turning of GFRP Composites: A Grey based Taguchi Approach." Thesis, 2015. http://ethesis.nitrkl.ac.in/6792/1/Optimization__Mahananda_2015.pdf.
Full textAbstract:
Glass fiber-reinforced polymer (GFRP) composites have made their applications increasingly noticeable mainly in the aerospace and automotive industries due to its lighter in weight and excellence mechanical properties. It has been found very difficult to assess the optimum process parameters responsible for machining. The thesis focuses on machining (turning) aspects of GFRP composites by using single point HSS cutting tool. The optimal setting i.e. the most favourable combination of process parameters (such as spindle speed, feed rate and depth of cut) has been obtained in view of multiple requirements of machining performance yields viz. tool tip temperature and surface roughness by using a grey Taguchi approach.
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Wang, K. D., and 王凱達. "Low Velocity Impact Response of Plain-Weaved and Double-Walled GFRP Composites Utilized A Drop-Weight Impact Tower." Thesis, 2000. http://ndltd.ncl.edu.tw/handle/24594329712814273314.
Full textAbstract:
碩士<br>國立成功大學<br>航空太空工程學系<br>88<br>The purpose of this thesis is to study the impact response and damage development of plain-weaved and Double-wall GFRP composites. The plain-weaved contain two different layers which are 8-plys and 11-plys, and double-walled include two types which are Parabeam-3mm and Parabeam- 6mm. We are using a Drop-Weight Impact Tower with a hemispherical tup in ascending impact Energy to do a series experiments for four laminates respectively. Utilizing the force Sensor (PCB) and data acquisition system (NI), we can get the impact force and absorbed energy histories in different impact energy. By the information of these curves, we can realize the condition of impact deformation、damage and energy absorbed during the impact. With comparing the relationship between the impact force and impact kinetic energy of each laminate, it could become the basis to estimate the ability of impact resistance.
In this thesis, we also introduce the “Energy-Balance Model” which could predict the impact force by balancing the impact kinetic energy of the impactor and the sum of strain energies due to each deformation. From the experiments, we know it should add the damage energy to the energy-balance equation to conform with really situations. Finally, we use the commercial finite element code MARC to simulate the behavior of impact. For the relative low velocity cases, the impact force and the velocity of impactor during impact are well captured for the plain-weaved.
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Sahu, Sharwan Kumar. "Drilling of Glass Fiber Reinforced Polymer (GFRP) Composites: Multi Response Optimization Using Grey Relation Analysis with Taguchi’s Method." Thesis, 2015. http://ethesis.nitrkl.ac.in/6789/1/DRILLING_Sahu_2015.pdf.
Full textAbstract:
Nowadays, GFRP (Glass Fiber Reinforced Polymer) composites are widely used in manufacturing industries specially aircraft, aerospace, and automobile industries due to their excellent mechanical and thermal properties such as more specific strength, better specific modulus of elasticity, high damping factor or damping capacity, better resistance to corrosion, effective fatigue resistance, low thermal expansion coefficient. Hence, it is necessary to understand the machinability behavior of these composites. Drilling is widely used to assemble the components in aforementioned industries. But machining of these composites is dissimilar to conventional metals due to their isotropic nature and in-homogeneity. Major drawbacks of these composites in machining are fiber pull out, delaminating and burring of fibers. So, appropriate selection of process parameters is an important concern in machining of GFRP composites. This work mainly focuses on assessing the effects of process parameters i.e. spindle speed, feed and drill diameter on thrust, torque, delamination factor (both at entry and exit) in drilling of GFRP composites using TiAlN coated drill bit. The study also utilizes the Grey methodology coupled with Taguchi L16 OA to determine the optimal parametric combination.