This chapter describes nondestructive evaluation (NDE) test methods and their relative effectiveness for diagnosing the cause of stress-corrosion cracking (SCC) service failures. It discusses procedures for analyzing various types of damage in carbon and low-alloy steels, high-strength low-alloy steels, hardenable stainless steels, austenitic stainless steels, copper-base alloys, titanium and titanium alloys, aluminum and aluminum alloys, and nickel and nickel alloys. It identifies material-environment combinations where SCC is known to occur, provides guidelines on how to characterize cracking and fracture damage, and explains what to look for during macroscopic and microscopic examinations as well as chemical and metallographic analyses. It also includes nearly a dozen case studies investigating SCC failures in various materials.

This chapter discusses the role of inverse analysis in providing input data for finite element simulations of metal forming processes. It describes the basic procedures for determining flow stress and friction by inverse analysis and for comparing experimental measurements with corresponding computed data. It also includes an example in which flow stress and friction were measured in compressed aluminum rings and the results used to verify the accuracy of predicted values.

This appendix is a compilation of suggested analysis methods for suspected component failure causes.

This chapter summarizes the various kinds of gear wear and failure and how gear life in service is estimated and discusses the kinds of flaws in material that may lead to premature gear fatigue failure. The topics covered are alignment, gear tooth, surface durability and breakage of gear tooth, life determined by contact stress and bending stress, analysis of gear tooth failure by breakage after pitting, and metallurgical flaws that reduce the life of gears. The chapter briefly reviews some components in the design and structure of each gear and/or gear train that must be considered in conjunction with the teeth to enhance fatigue life.

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 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.

Stress severity factors are used in design and analysis to account for stress concentrations, variations in material properties and fabrication quality, and other analytical uncertainties. They indicate the severity of stress in areas that are prone to crack development. This appendix discusses stress severity factors associated with fastener holes in attachment joints.

Fracture mechanics is a well-developed quantitative approach to the study of failures. This chapter discusses fracture toughness and fracture mechanics, linear-elastic fracture mechanics, and modes of loading. The discussion also covers plane strain and stress and crack growth kinetics. The chapter presents a case history that illustrates the use of fracture mechanics in failure analysis. An appendix provides a more detailed discussion of fracture mechanics concepts.

This chapter reviews the fundamentals of stress, strain, and deformation and demonstrates some of the tools and techniques used to analyze how materials and structures respond to tension, compression, bending, and shear. It begins with an overview of the behavior of perfectly elastic and plastic materials and viscous substances. It then describes the stress-strain response of two- and three-dimensional solids, explaining how to determine principle stresses and strains using Mohr’s circle and how to derive equivalent stress and strain using the von Mises relationship. It then goes on to analyze the stress state of load-bearing members, pressurized tubes, and pin-loaded lugs, accounting for the effect of geometric discontinuities, such as cutouts, fillets, and holes, as well as cracks. It also explains how finite element methods are used to solve problems involving complex geometric and loading conditions.

This chapters discusses the basic steps in the failure analysis process. It covers examination procedures, selection and preservation of fracture surfaces, macro and microfractography, metallographic analysis, mechanical testing, chemical analysis, and simulated service testing.

This chapter focuses on common failure characteristics exhibited by mechanical and electrical components. The topic is considered from two perspectives: one possibility is that the system failed because parts were nonconforming to drawing requirements and another possibility is that the system failed even though all parts in the system met their drawing requirements. The common failures discussed in this chapter include those associated with metallic components, composite materials, plastic components, ceramic components, and electrical and electronic components.

This chapter discusses the use of finite-element modeling in forging design. It describes key modeling parameters and inputs, mesh generation and computation time, and process modeling outputs such as metal flow, strain rate, loading profiles, and microstructure. It also includes a variety of application examples.

This appendix focuses on procedures, techniques, and precautions associated with the investigation and analysis of metallurgical failures that occur in service. It describes the steps of an orderly failure analysis from collecting and examining samples to performing mechanical and nondestructive tests, preparing and examining fractographs and micrographs, determining failure mode, writing the report, and developing follow-up recommendations. It also examines the fundamental mechanisms of failure, why they occur, and how to identify them by their characteristic features.