This chapter is a brief account of various factors pertinent to the development of an engineering component. The discussion covers the disciplines and interactions of design development, engineering of component design, validation of design and process analysis, and matrix of design and manufacturing elements.

This chapter explains how the authors assessed the potential risks of creep-fatigue in several aerospace applications using the tools and techniques presented in earlier chapters. It begins by identifying the fatigue regimes encountered in the main engines of the Space Shuttle. It then describes the types of damage observed in engine components and the methods used to mitigate problems. It also discusses the results of analyses that led to changes in design or approach and examines fatigue-related issues in turbine engines used in commercial aircraft.

This chapter focuses on high-pressure cold spray applications pertaining to repair and refurbishment in the aerospace, oil and gas, and power-generation industries, the last specifically involving repair of gas turbine components. Advantages of cold spray coating in the repair and refurbishment of structural engineering components are also discussed.

This chapter focuses on tensile testing of three types of engineering components that undergo significant loading in tension, namely, threaded fasteners and bolted joints; adhesive joints; and welded joints. It describes the standardized tensile test for externally threaded fasteners and provides a brief background on relationships among torque, angle-of-turn, tension, and friction. The chapter also describes the test methods covered in the ASTM F 606M standard, namely, product hardness; proof load by length measurement, yield strength, or uniform hardness; axial tension testing of full-sized products; wedge tension testing of full-sized products; tension testing of machined test specimens; and total extension at fracture testing. Finally, the chapter covers tensile testing of adhesive and welded joints.

This chapter provides an overview of how the disciplines of design, material, and manufacturing contribute to engineering for functional performance. It describes the interaction of product designers and casting engineers in product development. It discusses the consequences of component failure, uncertainty in data and assumptions, and selection of the factor of safety. The chapter also presents an overview of the functional requirements for product performance and provides an overview of product design development. It also presents a partial list of the different tests that are performed on prototypes and examples of product testing. The chapter describes the requirements of a traceability system.

This chapter outlines the topics covered in the book and explains why and to whom the book was written. The book is intended for engineers, metallurgists, and failure analysts who work with materials and components that operate in high-temperature corrosive environments. It covers eight basic modes of high-temperature corrosion as well as the effect of external and residual stresses. It also provides an extensive amount of engineering data associated primarily with commercial alloys.

Metal particles were frequently detected in the oil of an aircraft engine, triggering an investigation that led to a torque sensor and its mounting components. The sensor assembly was removed and examined in greater detail. As the chapter explains, investigators discovered that one of the bearings had been subjected to excessive friction, evidenced by brinelling, metal flow, heat tinting, deformation, and wear. They also observed extensive grooving on a retaining plate and several washers matching the diameter of the outer bearing races. Based on their findings, investigators concluded that excessive clearance allowed the outer bearing races to rotate, thus removing material from adjacent contact surfaces and accelerating the buildup of metal particles in the engine oil. The chapter recommends several design changes to remedy the problem.

This article discusses the material and engineering issues associated with plastic components subjected to impact. The first part covers the effects of loading rate, temperature, and state of stress on both deformation and mode of failure. It discusses standard impact tests, along with their associated results. A brief discussion on the linear elastic fracture mechanics method is presented, along with an example of its effectiveness as a predictive tool for impact performance. Various issues with a bearing on impact performance, such as processing, chemical attack, and aging, are also described. The second part describes the engineering calculations used to predict the performance of thin plastic beams, plates, and shells. The issue of assuming small displacements for the calculation of plastic structure performance is discussed and its limitations described. An example of the consequence of the very low modulus of elasticity associated with plastics and some plastic design solutions are offered.

The casting engineer contributes to a successful component design by offering expertise in molding, core making, and material characteristics and by recommending the most suitable casting process to use to meet quality and cost targets. The casting engineer's responsibilities include recommending locator positioning; advising about lugs, hooks, or holes for casting handling through all processes; determining the choice of a parting plane and pouring orientation; designing cores for accurate positioning, suitable venting, and proper cleaning; guiding decisions about wall thicknesses and junctions; making suggestions about casting design to eliminate distortion; optimizing the gating design for slag-free metal; and establishing the feeding techniques to eliminate shrink porosity. This chapter provides the guidelines for these responsibilities. In addition, the guidelines for the use of chaplets and chills in cast iron castings; guidelines for drafts, machine stock, tolerances, and contraction or shrink rule; and guidelines for pattern layouts and nesting are also covered.

Many metallic components, such as retorts in heat treat furnaces, furnace heater tubes and coils in chemical and petrochemical plants, waterwalls and reheater tubes in boilers, and combustors and transition ducts in gas turbines, are subject to oxidation. This chapter explains how oxidation affects a wide range of engineering alloys from carbon and Cr-Mo steels to superalloys. It discusses the kinetics and thermodynamics involved in the formation of oxides and the effect of surface and bulk chemistry. It provides oxidation data for numerous alloys and intermetallics in terms of weight gain, metal loss, depth of attack, and oxidation rate. It also discusses the effect of metallurgical and environmental factors such as oxygen concentration, high-velocity combustion gas streams, chromium depletion and breakaway, component thickness, and water vapor.

This chapter addresses the cumulative effects of fatigue and how to determine its impact on component lifetime and performance. It begins by defining a loading history and its corresponding hysteresis loops that exposes the deficiencies of some of the theories discussed. It then proceeds to demonstrate the methods commonly used to analyze cumulative fatigue damage and its effect on component life starting with the classical linear damage rule. After pointing out the inherent limitations of the model, it presents a method that incorporates two linear damage rules, one applying prior to crack initiation and the other after the crack has started. Although the method accounts somewhat better for loading-order effects, the transition in behavior that the rules presume to model occurs prior to any signs of cracking. Two modified versions of the double linear damage rule method, neither of which are related to a physical crack initiation event, are subsequently presented along with several applications showing how the different methods compare. The examples provided include two-level and multilevel tests, a gas-turbine engine compressor disk, and the cumulative damage associated with the irreversible hardening of type 304 stainless steel.

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.

This appendix provides supplemental information on the metallurgical aspects of atomic structure, the use of dislocation theory, heat treatment processes and procedures, important engineering materials and strengthening mechanisms, and the nature of elastic, plastic, and creep strain components. It also provides information on mechanical property and fatigue testing, the use of hysteresis energy to analyze fatigue, a procedure for inverting equations to solve for dependent variables, and a method for dealing with the statistical nature of failure.

Joining comprises a large number of processes used to assemble individual parts into a larger, more complex component or assembly. The selection of an appropriate design to join parts is based on several considerations related to both the product and the joining process. Many product design departments now improve the ease with which products are assembled by using design for assembly (DFA) techniques, which seek to ensure ease of assembly by developing designs that are easy to assemble. This chapter discusses the general guidelines for DFA and concurrent engineering rules before examining the various joining processes, namely fusion welding, solid-state welding, brazing, soldering, mechanical fastening, and adhesive bonding. In addition, it provides information on several design considerations related to the joining process and selection of the appropriate process for joining.

This chapter discusses the role of plastic deformation in forging and the effect of strain and strain rate on metal flow. It demonstrates the use of stress tensors and shows how metal flow can be represented qualitatively by the displacement of volume elements and quantitatively by the distribution of velocity components and strain rates. It describes the conditions associated with homogeneous deformation in a frictionless upset forging and explains how they can also be obtained using engineering and true stress-strain curves.

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.

Abradable coatings (such as Ni-4Cr-4Al/bentonite) are used throughout jet engines, primarily as sacrificial coatings into which moving components wear. This article presents the Accepted Practice for sample preparation of abradable coatings for metallographic analysis, based on round robin testing by several laboratories.

This chapter begins with a brief review of the different types of surface treatments and coatings used in industry and their effect on properties and performance. It then discusses the importance of corrosion and wear treatments and the consequences of failing to properly implement them in critical industries such as mining, energy production, transportation, and mineral and chemical processing. The chapter also describes basic approaches to dealing with corrosion and wear in steel.

This chapter provides helpful guidelines for selecting a surface treatment for a given application. It identifies important design factors and applicable treatments for common design scenarios, materials, and operating conditions. It explains why heat treatments and finishing operations may be required before or after processing and how to estimate or predict coating thickness, case depth, hardness, and the likelihood of distortion. It also addresses related issues and considerations such as part handling and fixturing, surface preparation and cleaning requirements, processability, aesthetics, and the influence of design features.

This appendix contains several tables listing UNS numbers, common names, and descriptions of important titanium alloys and where they are typically used.