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Mock-Ups, Models, Simulations, and Embedded Testing
Published in Samuel G. Charlton, Thomas G. O’Brien, Handbook of Human Factors Testing and Evaluation, 2019
Valerie J. Gawron, Thomas W. Dennison, Michael A. Biferno
Foam Core, Mock-ups are very economical for validating spatial relationships because they can be made from inexpensive materials. Foam core is a thin sheet of dense Styrofoam™ (usually ⅛ or 316 in. thick), covered with white paper on both sides. It is readily available from office supply stores and is very easy to work with. It can be cut with an X-acto™ knife and joined using a hot glue gun. Full-scale, two-dimensional drawings or photographs can be pasted to surfaces for added realism (see Fig. 9.1). Foam core is not, however, a rugged material; it will not support an operator’s weight or forceful use. If ruggedness is required, foam core can be built on a structure of wood or some other rigid material (see Fig. 9.2). Cardboard, foam block, or modeler’s clay can also be used to construct simple mock-ups. These materials all vary in their cost, skill required, strength, and fidelity. For example, cardboard is relatively flimsy but easy to work with. A mock-up made from modeler’s clay can look nearly identical to the finished product, but it is labor intensive and requires skill and experience to develop.
Design and prototype manufacture of a composite bicycle frame
Published in Steve Haake, The Engineering of Sport, 2020
The bottom bracket shell was made of 2017 T3 alloy. All alloy parts were wrapped in a layer of woven glass mat/epoxy resin to avoid galvanic corrosion. The seat tube and head tube was made by wrapping a single layer of woven glass/epoxy followed by layers of woven carbon/epoxy to a total thickness of 1 mm around a aluminium mandrel of appropriate diameter. All inserts were fitted to the jig and secured in place. Then the prepared foam core was bonded to these parts using epoxy resin adhesive. The foam core proved sufficiently rigid to assemble the crucial parts (rear wheel, crank arms and chain). Slight misalignments were corrected at this stage. At the same time, the front fork was built, using steel tubes, and aligned on a special jig.
Material selections and product prototyping
Published in Fuewen Frank Liou, Rapid Prototyping and Engineering Applications, 2019
When selecting a material, material properties are critical since they are the link between basic material composition and service performance. Material processing is also critical since it determines part manufacturing processes. Prototyping materials often are different from the final product materials, especially for lower fidelity prototypes, due to the differences in project objectives and time constraints in prototyping. For quick prototyping purposes, there are several materials available. Modeling clay: As shown in Figure 4.1, modeling clay is easy to work with, is useful for visualization and airflow studies, always remains soft, and is available in hobby and craft shops. Each time Congress authorizes a new coin or medal, an artist sketches out ideas for the design. After one design has been approved, the U.S. Mint sculptor-engraver sculpts a clay model as shown in Figure 4.1 [USMint17].Machining wax: Wax can be machined well and is low in cost and useful for prototyping tooling patterns.Foam board: As shown in Figure 4.2, the foam board has a good finish and is easily carved, useful for painting (aesthetic/appearance models), and machinable. Pressurized cans of insulating foam are available that harden quickly and may be cut and formed with a knife and sanding board. Foam core: As shown in Figure 4.3, the foam core is made of sheets of hard paper with internal foam, is useful for mock-ups and layout of square objects, can be used with Bondo/clay for more complex shapes, and is more durable and rigid than cardboard. Rubber and elastomer: As shown in Figure 4.4, rubber and elastomer are useful in energy absorption applications or seals, can be used as a removable mold for castings of other materials, and can be carved.Cardboard, paper, and cloth: Cloth and paper can serve as joints in mock-ups and are very economical.
On the pacifying influence of an elastomeric foam core on the failure mechanism of sandwich composites with various skin layups
Published in International Journal of Crashworthiness, 2023
To highlight the influence of compressibility and recoverability of the core in sandwich beams, an elastomeric foam made of a blend of polyethylene and ethylene-vinyl-acetate (PE-EVA) was selected for this purpose. The combination of PE and EVA creates a cross-linked material with linear chains, which provide hardness depending on the PE content while EVA content governs the degree of the blend. The superior durability and chemical resistance of this foam has made it an attractive choice for the fabrication of components in various industries. The perforated structure of this foam enables the foam to expel air when compressed and suck up the air during its recovery upon unloading [19]. A relatively stiffer grade of this foam with a room temperature density of 224 kg/m3 by 10 mm of thickness was employed in this study. The bonding adhesive used to mate the skins and the foam core was an epoxy adhesive film. The properties of the elastomeric foam and adhesive film are provided in Tables 1 and 2, respectively.