Skin reinforcement

Often the use of stainless-steel reinforcement is hmited to the outer part of the structure (skin reinforcement) or to its most critical parts for economical reasons. Furthermore, when stainless-steel bars are used in the rehabihtation of corroding structures, they are usually connected to the original carbon-steel rebars. Concern has been expressed with regard to the risk of galvanic corrosion of carbon steel induced by coupHng with stainless-steel bars. Actually, the galvanic corrosion that can arise when stainless steel is used in partial substitution of carbon steel has to be compared with that which takes place in the absence of stainless steels [30]. 

The IWL liposomes have a beneficial effect on intact skin, reinforcing its barrier integrity and imi oving its water-holding capacity. 

Unfilled skin/reinforced core High surface finish, structural performance Automotive door handles... 

Figure 3.11 Comparison of stiffness of carbon fiber-reinforced polymer (FRP) with carbon FRP applied as skin reinforcement to a lightweight polypropylene honeycomb core.

Many cellular plastic products are available with different types of protective faces, including composite metal and plastic foils, fiber-reinforced plastic skins, and other coatings. These reduce but do not eliminate the rate of aging. For optimum performance, such membranes must be totally adhered to the foam, and other imperfections such as wrinkles, cuts, holes, and unprotected edges should be avoided because they all contribute to accelerated aging. 

Sanitary ware, including tubs, showers, combined units, basins, and toilet tank, may be made of thermoformed ABS or acryHc sheet, molded glass-fiber-reinforced polyester, or cast acryHc resins. The glass-polyester type dominates the tub/shower market. It is possible to install the units as a two-component system, assembled in place. Gel coats may be of thermoformed decorative acryHc skins. To reduce the smoke generated by fire, methyl... 

Traditional cold store construction was to build an insulated lining within a masonry shell. The outer skin would be erected in brick and concrete, and rendered as smooth as possible inside with cement plaster, to take the insulation. When the surface was dry, it would have several coats of bitumen applied as a vapour barrier and slabs of insulation material stuck to this with hot bitumen. This was normally carried out in two or more layers so that joints did not pass right through the insulant, but were staggered. The inner skin would be finished with cement plaster, reinforced with wire mesh. The usual insulant was slab cork. 

Different core materials are used. They include foam, honeycomb core (plastic, paper, aluminum, etc.), ribs, balsa wood, filler spacers, corrugated sheet spacers, etc. Materials such as polyurethane foam, cellulosic foams, and polystyrene foams are widely used as core materials. Plastics, such as glass-reinforced polyester, are frequently used as the skins for panels. Different skin materials are used such as metallic skins alone or in conjunction with plastic skins. 

The type of shelf design is the next consideration. The shelf can be a solid plate of plastic material, an inverted pan-like structure with reinforcing ribs, a sandwich-type structure with two skins and an expanded core, or even a lattice type sheet that has a series of openings. The choice between these is dictated by a number of factors. One is appearance or aesthetics. 

The lattice-type shelf is functionally as good as the others, but it may not look appropriate for a book shelf in the context of a library. A second consideration is a combination of physical requirements and appearance. A simple plastic beam that will function adequately in terms of strength and stiffness may be rather thin. A shelf of this type can look flimsy even if it is functional. This impression is useful to the designer since the solid plate is probably an uneconomical use of material. A requirement was added that the design should look like a wood shelf since this is the context in which it is to be used. To produce the desired thickness appearance either a lipped pan with internal reinforcement can be used or, alternatively, a sandwich-type structure with two skins and a separator core. In either case the displacement of the material from the plane of bending will improve the stiffness efficiency of the product. The appropriate procedure is to... 

The chassis is made from a 1/4 in. sheet of either ABS or TPO vacuum formed into a tub and reinforced with reinforced pultruded glass fiber-TS polyester plastic tubing. The hood and other products are being made from a 20 mm thick sandwich of thermo-formed PPO-alloy skins, glass fabric infused with thermosetting vinyl ester, and a urethane foam core. The bumper and front fascia is thermoformed from a polyolefin elastomer sheet with an UV-resistant cap layer of DuPont s Tediar PVF film. The dash and... 

External panels of house or building with glass fibre reinforced plastic (GFRP) skins... Disposable formworks. .. 

Frontages in sandwich made of PVC foam core and skins of fire-resistant glass fibre reinforced polyester. The panels are attached onto a steel framework. 

Venture Industries is patenting Sandwiform glass-reinforced polypropylene structural sandwich material. Panels with decorative skins are formed in a one-step, thermo-compression process for trunk elements. 

Aerospace, top-of-the-range sports and leisure the core is generally made of honeycombs or high-performance foams and the skins can be made of carbon fibre reinforced thermoplastic polyimides. 

The cohesion of the matrix and reinforcements can be damaged, even in the bulk, by moisture or chemical surface attack. The fluids can propagate to some depth by absorption and wicking consequently it is important that a skin protects the reinforcements from direct contact with the external environment. 

In a sandwich structure, the foam is used as the core with two skins of reinforced resin sheets firmly stuck on the foam to obtain high rigidity. The sandwich composite behaves as an I-beam see Figure 6.11. 

The Ultratect foam from BASF is used as the core with glass fibre reinforced polypropylene skins for the sandwich rear seat backrest of the M3 CSL sports car by BMW. The weight saving is 50% versus a metal part. 

IF-18 is another proinflammatory cytokine which can support Th-1 responses [24]. Keratinocytes functionally respond to IL-18 with upregulation of MHC I, reinforcement of the IFN-y-induced MHC class II expression and production of the Th-1 attracting chemokine CXCLIO [25]. This supports the notion that IL-18 is involved in the pathogenesis of local Th-1 responses in chronic inflammatory skin diseases. 

Results are presented of experiments undertaken by Gaiker in the manufacture of sandwich panels containing foam cores based on PETP recycled by a solid state polyaddition process developed by M G Ricerche. Panels were produced with glass fibre-reinforced unsaturated polyester and epoxy resin skins, and allthermoplastic panels with PE, PP, PS and glass fibre-reinforced PETP skins were also produced. EVA hot melt adhesives and thermoset adhesives were evaluated in bonding glass fibre-reinforced PETP skins to the foam cores. Data are presented for the mechanical properties of the structures studied. 

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