Increasing concerns regarding human-driven effects on the biosphere have led to the development and adoption of environmentally friendly “green” composites. Unlike conventional synthetic composites, green composites are made of natural materials in either the matrix or the fiber reinforcement (or both). They are claimed to have lower negative environmental effects due to their sustainability and easier recyclability. To assess the environmental impacts associated with any product, a life cycle assessment (LCA) is needed. This literature review summarizes the individual steps undertaken in an LCA study and discusses their relevance within the field of green composites. Similarly, an outline of life cycle costing (LCC), a type of study which determines the economic implications of a product, is incorporated. Since some phases of a product’s life cycle can have significant environmental effects, parameters affecting the time-dependant degradation of green composites and their significance in LCA studies were also explored. Finally, criteria for choosing natural fibers and biopolymers for green composites in engineering applications were considered, and case studies of hemp and flax as candidates for fiber cultivation in Alberta, Canada are provided throughout.
With the rapid development of engineering and new demands of contemporary employers, post-secondary institutions have to adapt, improve and enhance engineering curricula to ensure that recent graduates possess appropriate levels of technical and professional skills and multilateral abilities for a successful start in industry. As industrial technologies, tools, and processes evolve, so must teaching methodologies and approaches, which significantly changes the structure of engineering courses. To ensure that students not only master technical knowledge but also develop their professional, interpersonal, cognitive and computer skills, engineering curricula have begun to shift from a classic instruction format to a blended learning format. Blended learning, the strategy of combining regular face-to-face instruction with online learning and/or other out-of-class-activities, is increasingly used in post-secondary education and disciplines and can take different forms depending on the course needs and desired learning outcomes. This paper reviews the recent implementation of blended learning in the form of gamification of a second-year introductory engineering design course using a commercial online learning platform. The reasoning, methodology, process and the results of student surveys before and after the online game are discussed along with suggested improvements.
In this design study, a model airplane wing, partially constructed from braided composite panels, was made for the purpose of demonstrating the applications of braided composites for aerospace components. Fibres of Kevlar® were braided together along a tubular surface, then subsequently cut and unrolled to form two planar sheets of interlaced yarns that could be laid down in a 3D printed mold to later be coated in resin. The mold consisted of four parts: two female parts to shape the composite wing panels and two male parts to compress the composite. When connected together they form a fused core. A fibre sheet was draped over each female part, and its extraneous edges were folded inward to form a second layer as reinforcement. Each sheet was then laid up with Ecopoxy® resin and allowed to cure while sandwiched between the female mold and its corresponding male component. Upon disassembly of the mold system, a braided composite wing panel had formed upon both halves of the 3D printed core. The external portion of each panel was found to be smooth with few irregularities that could potentially compromise their aerodynamic performance. The mold was constructed to facilitate the process of cold-curing rather than curing at an elevated temperature. For heated cure process, the use of metal would be recommended because it generally deforms negligibly through heating and cooling. A metal mold would also be used to ease the process of debonding from the composite materials. Care should be taken to ensure that fibre orientation is consistent. The results illustrate how a mold can be fabricated to facilitate the process of curing braided composites, and can serve to improve the quality of products that require a higher strength to weight ratio.
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