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Abstract: This paper presents a conceptual design of a satellite device to be used for capturing asteroids, based on inflatable structures. The mission requirements, the conceptual design, the methodology for the selection of the best solution, and simulations for the preliminarily structural analysis of the device are described within. Several finite element analyses have been carried out in order to find the best strategy to model flexible materials under internal pressure, and the device structure has been changed accordingly in order to obtain the best trade-off between weight and strength. This paper presents the sizing and the weight breakdown of the satellite inflatable components, which are quite complex to model with regards to the structural simulation. The results obtained seem to confirm the feasibility of such a structure and motivates further studies and experimental tests.
Keywords: Conceptual design | Fabric | FEM | Inflatable structure | MADM | α damping
Abstract: In this paper, a comparison between the mechanical characteristics of two different natural fiber composites has been carried out. The two composites were made using two different environmentally friendly resins, but with the same flax fiber reinforcement. Thirty-two specimens were tested for tension, bending and shear. The results obtained in the tensile and bending tests are acceptable according to the Standards, whereas those of the shear tests were discarded, since the samples exhibited unacceptable failure modes. In light of the results obtained, both in terms of strength and stiffness, the isophthalic resin (181EN2X) outperformed the vinyl ester resin (VEef220ST). In the case of the isophthalic resin, microscopic observations showed a good adhesion between the matrix and the fiber, with a small amount of air inclusions. The present study demonstrates that the mechanical characteristics of flax reinforced and environmentally friendly resins are similar to those achievable with the same fibers using conventional resins.
Keywords: Environmentally friendly resin | Flax | Mechanical properties | Natural fibre composites
Abstract: In this paper, the design of a prototype system developed for a rover intended for the removal and transport of rocks on lunar soil is reported. The part of the rover dedicated to some of the main tasks, i.e. the lifting of objects and moving on rugged terrain, while controlling of the balance of the vehicle, is considered. These tasks are accomplished through the mechanical components assembled in a column connected to wheels. The study has been conducted with the aim of obtaining a simple and lightweight structure satisfying the requirements necessary to operate on the lunar soil. After a description of the architecture of the rover, the layout of the components of the column is detailed. A compliant, spiral-spring wheel is proposed to complete the mobility system. The primary components of the column are then structurally assessed by means of FEM numerical simulations. A numerical model of the wheel has also been implemented, in order to define in detail the wheel geometry and performance. The proposed layout could be promising for lunar applications since it has a configuration suitable for the specific characteristics of the environment it has to operate.
Keywords: Column | Design | FEM simulation | Lunar environment | Wheel | Working operation
Abstract: Market always asks for new products in short time. It requires an introduction of new tools and methods for managing continuous product changes while evaluating their impact in terms of design efforts, manufacturing costs, time to market, etc in real time. The present research work aims at developing a design platform to support the creation, visualization and navigation of a multilevel product representation where functions, modules, assemblies and components are strictly interrelated. The introduction of "Design for X" principles as rules to relate all aspects contributing to product design, allows evaluating the impact of changes at three levels. The approach and the proposed platform have been applied in the field of refrigerators in order to support both designers and engineers in rapidly configuring the optimal design solution in respect of the company's requirements formalized by the implemented "Design for X" rules. © 2010 Journal of Mechanical Engineering.
Keywords: Change management | Design for X | Functional analysis and modularity | Impact of design changes
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