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151	Characterization of Fiber Orientation and Weld Line Effects in Reinforced Plastics with Reduced CO2eq Emissions Tolf, Anders, Johannesson, Markus January 2022 (has links) With increasing emphasis and regulations on the environmental footprint in industries, the integration of reduced carbon dioxide equivalent (CO2eq) plastic materials is desirable. Fiber-reinforced plastic materials mechanical properties differ with varying fiber orientations. Similarly, the welding line phenomenon, commonly present in more complex injection molded parts, decreases the mechanical performance. This thesis aims to experimentally investigate tensile behavior on reduced CO2eq reinforced plastics in different fiber orientations and weld line configurations. Ten materials with reduced CO2eq are investigated, the types of materials are as follows: PA6 (Polyamide6), PP (Polypropylene), and PA6/PP blend materials. Both short fiber-reinforced polymers (SFRP) and long fiber-reinforced polymers (LFRP) are investigated. The screening resulted in three selected materials for further investigation: one recycled PA6, one bio-based PA6/PP, and one alternative PP. The further investigation involves tensile testing in the five directions and three weld line configurations with non-standardized geometry specimens punched out from an injection molded plate with controlled fiber orientation. Two types of uniform fiber orientation plates are manufactured for the testing conditions, one with holes for weld line testing and one without for testing of orientation. The evaluated fiber orientations are 0° (fibers parallel to load direction), 22.5°, 45°, 67.5°, and 90° (fibers transverse to load direction). The weld line configuration consists of three consecutive holes with 96.5, 146.5, and 196.5 mm distances from the gating system. Three weld line test specimens are generated from each plate, they are denoted W1, W2, and W3 from their respective distance from the gating system, with W1 being closest to the gate. Optical microscopy of fiber orientation and failure modes for the test specimens are performed to investigate and validate the testing conditions. Varying fiber orientation was found to greatly affect the stress-strain behavior in all four materials investigated. The tensile strength was reduced from longitudinal to transverse fiber orientation, with the most significant reduction near flow direction. High variations were present for the brittle materials supposedly from their weakness to stress concentrations. Strain tended to increase from the lowest at 0° to the maximum at 45°, from which it again decreased to a mid-value at 90° for all materials. The weld line strength reduced significantly for the brittle materials, whereas the ductile materials experienced a much smaller reduction. The three weld line cases failed at similar stresses, while having different stiffness. Fiber-reinforced plastics GFRP Experimental Uniaxial tensile test Uniform fiber orientation plate Tensile strength Fiber orientation Weld line Fracture analysis Microscopy Textile, Rubber and Polymeric Materials Textil-, gummi- och polymermaterial Applied Mechanics Teknisk mekanik Composite Science and Engineering Kompositmaterial och -teknik Other Materials Engineering Annan materialteknik
152	All-Oxide Ceramic Matrix Composites : Thermal Stability during Tribological Interactions with Superalloys / Materiales Compuestos de Matriz Cerámica base Óxido : Estabilidad Térmica durante Interacciones Tribológicas con Superaleaciones Vazquez Calnacasco, Daniel January 2021 (has links) The challenges faced in today’s industry require materials capable of working in chemically aggressive environments at elevated temperature, which has fueled the development of oxidation resistant materials. All-Oxide Ceramic Matrix Composites (OCMC) are a promising material family due to their inherent chemical stability, moderate mechanical properties, and low weight. However, limited information exists regarding their behavior when in contact with other high-temperature materials such as superalloys. In this work three sets of tribological tests were performed: two at room temperature and one at elevated temperature (650 °C). The tests were performed in a pin-on-disk configuration testing Inconel 718 (IN-718) pins against disks made with an aluminosilicate geopolymeric matrix composite reinforced with alumina fibers (N610/GP). Two different loads were tested (85 and 425 kPa) to characterize the damage on both materials. Results showed that the pins experienced ~ 100 % wear increase when high temperature was involved, while their microstructure was not noticeably affected near the contact surface. After high temperature testing the OCMC exhibited mass losses two orders of magnitude higher than the pins and a sintering effect under its wear track, that led to brittle behavior. The debris generated consists of alumina and suggests a possible crystallization of the originally amorphous matrix which may destabilize the system. The data suggests that while the composite’s matrix is stable, wear will not develop uncontrollably. However, as soon as a critical load/temperature combination is attained the matrix is the first component to fail exposing the reinforcement to damage which drastically deteriorates the integrity of the component. Ceramic Matrix Composites Long Fiber Composites (LFC) Ceramic Fiber-Matrix Composites (CFMC) Fiber Reinforced Ceramics (FRC) Superalloys Inconel 718 Tribology Elevated Temperature Alumina Aluminosilicate Superaleaciones Inconel 718 Tribología Alta Temperatura Alumina Aluminosilicatos Other Materials Engineering Annan materialteknik Metallurgy and Metallic Materials Metallurgi och metalliska material Composite Science and Engineering Kompositmaterial och -teknik Ceramics Keramteknik
153	Preventing fatal effects of overworking : Product design solution Adawi, Rahim January 2018 (has links) “Overworking to death” is a phenomenon that has been noticeable in developing countries. The cause of death is mainly through ischemic strokes. While the victims’ occupations differed, they all shared a common characteristic, being positioned in a sedentary work, ranging from IT workers to doctors. This project’s aim was to develop a product that prevented or decreased the strokes that derived from sedentary overwork. This was mainly tackled by preventing one of the three causes of developing blood props, slowed blood flow. In order to gather rich data of the phenomenon, a qualitative study was conducted in China, during two months. By doing an extensive structured sampling, information rich data could be gathered during a short period of time. Data were derived from observations, questionnaires and an interview, which then was interpreted to customer needs and the final product specification. The final product became a trouser with an in built dynamic compression mechanic, that can compress the veins mostly during sitting activities, in order to prevent blood stasis. The compression mechanic works like the Chinese finger trap; compressing the calves while sitting and stretching the legs forward. It is made only out of polysaccharides fibres; cotton and corn. / "Guolaosi" eller död från överarbete är ett fenomen som i regel uppkommer bland utvecklingsländer. Dödsorsaken är huvudsakligen genom stroke. Offrens yrken varierar allt från professorer, IT-arbetare till läkare. De delar dock en sak gemensamt; att arbeta under långa perioder stillasittande. Projektets mål var att utveckla en produkt som minskar dödliga följderna av sedentära överarbete, genom att förebygga en av de tre orsakerna för att utveckla blodproppar; saktad blodström. Målgruppen var då kineser av de yrken som hade tidigare drabbats av fenomenet. För att samla informationsrika data om fenomenet genomfördes en kvalitativ studie i Kina under två månader. Genom att göra en omfattande strukturerad provtagning kunde informationsrika data samlas under en kort tidsperiod. Fältstudien bestod av observationer, frågeformulär och en intervju, som då tolkades till kundbehov och eventuellt produktspecifikationen. Den slutliga produkten kom att bli ett par byxor med en inbyggd dynamisk komprimeringsmekanism, som kan komprimera venerna under sittande aktiviteter, för att förhindra saktad blodström. Kompressionsmekanismen fungerar som den kinesiska fingerfällan. Den komprimerar blodkärlen medan personen sitter och sträcker benen framåt. Produkten är konstruerad på så sätt att den kan tillverkas endast av polysackariders tråd, från bomull och majs. Vilket är lämpligt för Kinas lokala resurser. stroke DVT overworking karoshi guolaosi prolonged inactivity sedentary death product design China Sweden Sida MFS field study trouser pants sampling observation questionnaire interview blood circulation stasis cardiovascular disease cotton corn agenda 2030 Chinese finger trap textile fibre yarn soil erosion muscle pump mechanism gradual compression stockings GECS PECS pressure distribution blood clot veins therapy stool chair PE PTS economy class syndrome methodology plastic sample concept sketch stroke DVT överarbete karoshi guolaosi förlängd inaktivitet stillasittande död produkt design Kina Sverige Sida MFS fältstudie byxa byxor provtagning observation frågeformulär intervju blodcirkulation stasis kardiovaskulär sjukdom bomull majs agenda 2030 kinesisk fingerfälla textil fiber garn jord erosion muskel pump mekanism gradvis komprimering strumpor stödstrumpa tryck kraft GECS PECS tryckfördelning blod blodproppar vener terapi pall stol PE PTS ekonomi klass syndrom metodik plast prov koncept skiss Design Design Pharmacology and Toxicology Farmakologi och toxikologi Occupational Therapy Arbetsterapi Cardiac and Cardiovascular Systems Kardiologi Environmental Sciences Miljövetenskap Medical Ergonomics Medicinsk ergonomi Textile, Rubber and Polymeric Materials Textil-, gummi- och polymermaterial Composite Science and Engineering Kompositmaterial och -teknik Medical Materials Medicinska material och protesteknik

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