Reinforced Plastic Performances

Applicable to RPs is the aspect ratio of fibers. It is the ratio of length to diameter (L/D) of a fiber. In RP fiber L/D will have a direct influence on the reinforced plastic performance. High values of 5 to 10 provide for good reinforcements. Theoretically, with proper lay-up the highest performance plastics could be obtained when compared to other materials. To maximize strength and modulus of RPs the long fiber approach is used. 

Aspect ratio It is the ratio of length (L) to diameter (D) of a material such as a fiber or rod also the ratio of the major to minor axis lengths of a material such as a particle. These ratios can be used in determining the effect of dispersed additive fibers and/or particles on the viscosity of a fluid/melt and in turn on the performance of the compound based on L/D ratios. In reinforced plastics, fiber L/D will have a direct influence on the reinforced plastic performance. 

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. 

High performance composites may be laminates wherein veils of carbon fiber ate treated with an epoxy resin, stacked up to the desired final product thickness, and then laminated together under heat and pressure (see Composite materials Carbon and graphite fibers). Simply mixing together carbon or glass fibers and polymeric resins to form a reinforced plastic leads to a composite material, but this is not a laminate if not constmcted from discrete phes. 

The business climate of the 1990s is different from the past. Factors such as increased competition, a global marketplace, rapid technical shifts, and greatly compressed product life cycles constantly open new opportunities for plastics in general and reinforced plastics in particular. Reinforced plastics have become widely accepted for particular appHcations because they offer a combination of design, performance, and economic benefits to the user. These materials have had a proven record of success since the 1940s. 

In this book no prior knowledge of plastics is assumed. Chapter 1 provides a brief introduction to the structure of plastics and it provides an insight to the way in which their unique structure affects their performance. There is a resume of the main types of plastics which are available. Chapter 2 deals with the mechanical properties of unreinforced and reinforced plastics under the general heading of deformation. The time dependent behaviour of the materials is introduced and simple design procedures are illustrated. Chapter 3 continues the discussion on properties but concentrates on fracture as caused by creep, fatigue and impact. The concepts of fracture mechanics are also introduced for reinforced and unreinforced plastics. 

The choice of manufacturing technology for the fabrication of fiber-reinforced plastics or composite materials is intimately related to the performance, economics, and application of the materials. It also depends upon a number of factors, such as component numbers required, item complexity, number of molded surfaces, and type of reinforcement. 

Performance testing of steel and reinforced plastic sucher rods by the mixed string alternate rod method... 

Reinforced plastic In common with metals and unreinforced plastics, RPs also is susceptible to fatigue. However, they provide high performance when compared to un-... 

Table 3-1 gives typical mechanical property data for four materials, the exact values of which are unimportant for this discussion. Aluminum and mild steel have been used as representative metals and polypropylene (PP) and glass fiber-TS polyester reinforced plastics (GRP) as representative plastics. Higher-performance types could have been selected for both the metals and plastics, but those in this table offer a fair comparison for the explanation being presented. 

Plastic also refers to a material that has a physical characteristic such as plasticity and toughness. The general term commodity plastic, engineering plastic, advanced plastic, advanced reinforced plastic, or advanced plastic composite is used to indicate different performance materials. These terms and others will be reviewed latter in this chapter. Plastics are made into specialty products that have developed into major markets. An example is plastic foams that can provide flexibility to rigidity as well as other desired properties (heat and electrical insulation, toughness, filtration, etc.). 

Coleman JN, Cadek M, Blake R, Nicolosi V, Ryan KP, Belton C, et al. High-performance nanotube-reinforced plastics Understanding the mechanism of strength increase. Advanced Functional Materials. 2004 Aug 14(8) 791-8. 

Choosing a reinforced plastic or one from a more-sophisticated polymer family to provide higher performance can be used to cut overall costs by reducing wall thickness and thus reducing material weight and material cost and enhancing the processing. 

There are no simple rules of thumb in defining the cost of reinforced plastic components. Their successful use has resulted from proper design, utilizing the benefits these materials offer, process selection, tooling cost advantages that fit the production needs, and consideration of life cycle economics. Each existing application illustrates the cost-performance advantage of reinforced plastic over the traditional material that is displaced. 

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