This chapter covers the friction and wear behaviors of plastics and elastomers. It begins by describing the molecular differences between the two types of polymers and their typical uses. It then discusses the important attributes of engineering plastics and their suitability for applications involving friction, erosion, and adhesive and abrasive wear. It also discusses the tribology of elastomers and rubber along with their basic differences and the conditions under which they produce Schallamach waves. It includes information on polymer composites as well.

This article briefly reviews abrasive and adhesive wear failure of reinforced polymers and polymer composites, namely particulate-filled polymers, short-fiber-reinforced polymers, polymers with continuous fibers, and mixed reinforcements and fabrics. It includes scanning electron microscope micrographs of abraded surfaces of composites against 80-grade SiC paper and under 14 N load, and worn surfaces of abraded polyether-imide composites and polyamide 66 unidirectional composites and 66 hybrid composites.

The challenge of materials selection is to achieve adequate performance at the lowest possible cost. Corrosion resistance is not the only property to be considered in making materials selections. Typical requirements and some of the procedures involved in making a selection and some of the factors that must be considered when determining the corrosion performance of a given material are listed in this chapter. The various steps that might be included in a materials selection process are then examined. These include a review of operating conditions and design, the selection of candidate materials, the in-depth evaluation of each candidate material, fabrication requirements, follow-up monitoring, and final materials selection. Material considerations such as cost, materials properties, and processing and fabrication requirements are subsequently covered. Finally, the chapter provides information on materials selection under general corrosion conditions and under conditions of localized corrosion forms such as pitting, crevice corrosion, and stress-corrosion cracking.

This chapter examines the static, fatigue, and damage tolerance properties of glass, aramid, and carbon fiber systems. It also explains how delaminations, voids, porosity, fiber distortion, and fastener hole defects affect impact resistance and strength.

The objective of mechanical testing of an engineered material is to provide data necessary for the analysis, design, and fabrication of structural components using the material. The testing of filament-wound composite materials offers unique challenges because of the special characteristics of composites. This chapter describes suitable static mechanical test techniques for characterizing laminated composite materials. The approach is to provide recommended techniques, based on consensus opinions of fabricators and users of filament-wound composites, and to survey available techniques that have been used successfully in the field. The chapter describes the effects of various factors on the properties of composite constituents, including fibers, resins, and unidirectional plies. Some aspects of specimen selection are also described. The chapter provides information on pressure bottles and tubular parts that have been developed as standard test specimens for combined load testing of composites.

This chapter discusses the ways in which the evolution of filament winding software systems has capitalized on the inherent flexibility of computer numerical controlled winding machines and enhanced their productivity. It provides a detailed discussion on different types of geometries that can be wound, from the simple to the highly complex, with insight into the limitations, advantages, and challenges of each. Components covered include classic axisymmetric parts (rings, pipes, driveshafts, pipe reducers, tapered shafts, closed-end pressure vessels, and storage tanks), nonround sections (aeromasts, airfoils, box sections, and fuselage sections), curved-axis parts (elbows, ducts), and special applications (tees). Basic winding concepts, such as band pattern, are discussed and explained, and some simple predictive formulae are introduced. The chapter also provides examples of programming various geometries using advanced software tools and discusses how various materials, such as rovings, tow-preg, prepreg tape, and woven materials, affect winding program generation.

This chapter consists of three parts. The first part provides data and guidelines for selecting materials and processing routes. It compares the basic properties of metals, ceramics, and polymers, identifies important measures of performance, and discusses manufacturing processes and their compatibility with specific materials. The chapter then presents general guidelines for selecting lightweight materials, and concludes with a review of lightweight metals, plastics, and composites used in automotive applications.

This article describes key processing methods and related design, manufacturing, and application considerations for plastic parts and includes a discussion on materials and process selection methodology for plastics. The discussion covers the primary plastic processing methods and how each process influences part design and the properties of the plastic part. It also includes a brief description of functional requirements in process selection; an overview of various process effects and how they affect the functions and properties of the part; and the selection of processes for size, shape, and design detail factors.

This chapter discusses the types of fibers and matrix materials used in ceramic matrix composites and the role of interfacial coatings. It describes the methods used to produce ceramic composites, including powder processing, slurry infiltration and consolidation, polymer infiltration and pyrolysis, chemical vapor infiltration, directed metal oxidation, and liquid silicon infiltration.

Ceramic-matrix composites possess many of the desirable qualities of monolithic ceramics, but are much tougher because of the reinforcements. This chapter explains how reinforcements are used in ceramic-matrix composites and how they alter energy-dissipating mechanisms and load-carrying behaviors. It compares the stress-strain curves for monolithic ceramics and ceramic-matrix composites, noting improvements afforded by the addition of reinforcements. It then goes on to discuss the key attributes, properties, and applications of discontinuously reinforced ceramic composites, continuous fiber ceramic composites, and carbon-carbon composites. It also describes a number of ceramic-matrix composite processing methods, including cold pressing and sintering, hot pressing, reaction bonding, directed metal oxidation, and liquid, vapor, and polymer infiltration.

This chapter discusses the effect of fiber length and orientation on the strength and stiffness of discontinuous-fiber composites. It also describes several fabrication processes, including spray-up, compression molding, reaction injection molding, and injection molding.

All materials are susceptible to corrosion or some form of environmental degradation. Although no single material is suitable for all applications, usually there are a variety of materials that will perform satisfactorily in a given environment. The intent of this chapter is to review the corrosion behavior of the major classes of metals and alloys as well as some nonmetallic materials, describe typical corrosion applications, and present some unique weaknesses of various types of materials. It also aims to point out some unique material characteristics that may be important in material selection, and discuss, where appropriate, the characteristic forms of corrosion that attack specific materials. The materials addressed in this chapter include carbon steels, weathering steels, and alloy steels; nickel, copper, aluminum, titanium, lead, magnesium, tin, zirconium, tantalum, niobium, and cobalt and their alloys; polymers; and other nonmetallic materials, including rubber, carbon and graphite, and woods.

This chapter describes the molecular structures and chemical reactions associated with the production of thermoset and thermoplastic components. It compares and contrasts the mechanical properties of engineering plastics with those of metals, and explains how fillers and reinforcements affect impact and tensile strength, shrinkage, thermal expansion, and thermal conductivity. It examines the relationship between tensile modulus and temperature, provides thermal property data for selected plastics, and discusses the effect of chemical exposure, operating temperature, and residual stress. The chapter also includes a section on the uses of thermoplastic and thermosetting resins and provides information on fabrication processes and fastening and joining methods.

Engineers have many materials to choose from when dealing with weight-related design constraints. The list includes aluminum, beryllium, magnesium, and titanium alloys as well as engineering plastics, structural ceramics, and polymer-, metal-, and ceramic-matrix composites. This chapter provides a brief overview of these lightweight materials, discussing their primary advantages along with their properties, behaviors, and limitations.

This article describes the mechanisms of moisture-induced damage in polymeric materials, covering the characteristics of important structural plastics; the effects of moisture on glass transition temperature, modulus, creep, and stress relaxation of plastic materials; and moisture-induced fatigue failure in composites. The effect of moisture on the mechanical properties of thermoset resins and thermoplastics are also discussed.

This introductory article describes the various aspects of chemical structure and composition that are important to an understanding of polymer properties and their eventual effect on the end-use performance of engineering plastics, namely thermoplastics and thermosets. The most important properties of polymers and the most significant influences of structure on those properties are covered. The article also includes some general information on the classification and naming of polymers and plastics.

The hot-working process extrusion is used to produce semifinished products in the form of bar, strip, and solid sections, as well as tubes and hollow sections. The first part of this chapter describes the composition, properties, and applications of tin and lead extruded products with a deformation temperature range of 0 to 300 deg C and magnesium and aluminum extruded products with a working temperature range of 300 to 600 deg C. The second part focuses on copper alloy extruded products, extruded titanium alloy products, and extruded products in iron alloys with a working temperature range of 600 to 1300 deg C.

To ensure the proper application of plastics, one must keep in mind three factors that determine the appropriate end-use: material selection, processing, and design. This article begins by providing information on various factors pertinent to the anticipated use conditions of the article to be designed. This is followed by a discussion on several stages necessary to define the geometry of plastic parts. Details on the strength of and cost estimation for plastic parts are then provided. The article ends with a section providing information on the structure, properties, processing, and end-use applications of plastics.

Polymer-matrix composites are among the lightest structural materials in use today. They are also highly resistant to corrosion and fatigue and their load-carrying capabilities, such as strength and stiffness, can be tailored for specific applications. This chapter discusses the primary advantages and disadvantages of polymer-matrix composites, how they are produced, and how they perform in different applications. It describes the construction of laminates, the fibers and resins used, and the methods by which they are combined. It explains how strength, modulus, toughness, and high-temperature and corrosion behaviors are determined by the orientation, shape, and spacing of fibers, the number of plies, resin properties, and consolidation and forming methods. The chapter also covers secondary fabrication processes, such as thermoforming, machining, and joining, as well as production equipment and product forms, and include guidelines for optimizing tradeoffs when selecting fibers, resins, and production techniques.