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 briefly outlines some of the basic aspects of failure analysis, describing some of the basic steps and major concerns in conducting a failure analysis. A brief review of failure types from fracture, distortion, wear-assisted failure, and environmentally assisted failure (corrosion) is also provided.

This chapter discusses some of the more advanced methods and procedures used in failure analysis, including in-service material sampling, in situ microstructure analysis, and a form of punch testing that can determine the fracture toughness of any material from a tiny specimen. The chapter also covers quantitative fractography, fracture surface topography analysis, and the use of oxide dating as well as fault tree and failure modes and effects analysis (FMEA) and computational techniques.

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.

Passive components can be broadly divided into capacitors, resistors, and inductors. Failure analysis of these components helps determine the root cause and improve the overall quality and reliability of the electronic systems. This article describes different failure analysis approaches used for these components. It discusses different types of capacitors along with their constructions and failure modes. The types include tantalum, aluminum electrolytic, multi-layered ceramics, film, and super capacitors. The article then provides a discussion on the two common types of inductors, namely, common mode choke coil and surface mount powder choke coil.

Failure mode assessment and assignment (FMA&A) is a tool designed to help organize the evaluation of hypothesized failure modes. This chapter begins by describing the process of preparing an FMA&A. It then describes the follow-on activities to evaluate the hypothesized failure cause. The chapter also provides information on evaluating the hypothesized potential causes.

Semiconductor memories are superb drivers for process yield and reliability improvement because of their highly structured architecture and use of aggressive layout rules. This combination provides outstanding failure signature analysis possibilities for the entire design, manufacturing, and test process. This article discusses five key disciplines of the signature analysis process that need to be orchestrated within the organization: design for test practices, test floor data collection methodology, post-test data analysis tools, root cause theorization, and physical failure analysis strategies.

The ultimate goal of the failure analysis process is to find physical evidence that can identify the root cause of the failure. Transmission electron microscopy (TEM) has emerged as a powerful tool to characterize subtle defects. This article discusses the sample preparation procedures based on focused ion beam milling used for TEM sample preparation. It describes the principles behind commonly used imaging modes in semiconductor failure analysis and how these operation modes can be utilized to selectively maximize signal from specific beam-specimen interactions to generate useful information about the defect. Various elemental analysis techniques, namely energy dispersive spectroscopy, electron energy loss spectroscopy, and energy-filtered TEM, are described using examples encountered in failure analysis. The origin of different image contrast mechanisms, their interpretation, and analytical techniques for composition analysis are discussed. The article also provides information on the use of off-axis electron holography technique in failure analysis.

Fracture is the separation of a solid body into two or more pieces under the action of stress. Fracture can be classified into two broad categories: ductile fracture and brittle fracture. Beginning with a comparison of these two categories, this chapter discusses the nature and causes of these failure modes. Some body-centered cubic and hexagonal close-packed metals, and steels in particular, exhibit a ductile-to-brittle transition when loaded under impact and the chapter describes the use of notched bar impact testing to determine the temperature at which a normally ductile failure transitions to a brittle failure. The discussion then covers the Griffith theory of brittle fracture and the formulation of fracture mechanics. Procedures for determination of the plane-strain fracture toughness are subsequently covered. Finally, the chapter describes the effects of microstructural variables on fracture toughness of steels, aluminum alloys, and titanium alloys.

This article reviews various analytical techniques most commonly used in plastic component failure analysis. The description of the techniques is intended to make the reader familiar with the general principles and benefits of the methodologies. The descriptions of the analytical techniques are supplemented by a series of case studies that include pertinent visual examination results and the corresponding images that aided in the characterization of the failures. The techniques covered include Fourier transform infrared spectroscopy, differential scanning calorimetry, thermogravimetric analysis, thermomechanical analysis, and dynamic mechanical analysis. The article also discusses various analytical methods used to characterize the molecular weight distribution of a polymeric material. It provides information on a wide range of mechanical tests that are available to evaluate plastics and polymers, covering the various considerations in the selection and use of test methods.

This chapter discusses the use of mechanical fastening and adhesive bonding, the primary methods for joining polymer matrix composites. It describes and analyzes the basic types of mechanically fastened joints, including single-hole and multirow bolted composite joints. It then reviews the advantages and disadvantages of adhesively bonded joints and compares and contrasts the long-term performance of various joint designs. The chapter also discusses the merits of stepped-lap and bonded-bolted joints.

After the fault-tree, a failure-cause identification method has identified potential failure causes and the failure analysis team has prepared a failure mode assessment and assignment (FMA&A). The team knows specifically what to search for when examining components and subassemblies from the failed system. There are numerous techniques and technologies available for examining and analyzing components and subassemblies, which are categorized as follows: optical approaches, dimensional inspection and related approaches, nondestructive test approaches, mechanical and environmental approaches, and chemical and composition analysis for assessing material characteristics. This chapter is a detailed account of the working principle and the steps involved in these techniques and technologies.

This chapter discusses the failure mechanisms associated with fiber-reinforced composites. It begins with a review of fiber-matrix systems and the stress-strain response of unidirectional lamina and both notched and unnotched composite laminate specimens. It then explains how cyclic loading can lead to delamination, the primary failure mode of most composites, and describes some of the methods that have been developed to improve delamination resistance, assess damage tolerance, determine residual strength, and predict failure modes.

Gears can fail in many different ways, and except for an increase in noise level and vibration, there is often no indication of difficulty until total failure occurs. This chapter begins with the classification of gear failure modes, followed by sections discussing the characteristics of various fatigue failures. Then, it provides information on the modes of impact fractures, wear, scuffing, and stress rupture. Next, the chapter describes the causes of gear failures and discusses the processes involved in conducting the failure analysis. Finally, the chapter presents examples of gear failure analysis.

After several failed attempts to lower their starboard wheels for landing, pilots engaged the help of gravity through g-force maneuvers and managed to coax the wheels into place. An inspection following the incident revealed a broken universal joint in one of the linkages that opens and closes the doors to the undercarriage compartment. The failed component was removed from the aircraft and examined using optical and electron microscopes. Under low magnification, the fracture surface appeared jagged except for one corner that was relatively smooth. SEM fractography revealed the presence of fatigue striations in the smooth region and dimpling elsewhere. Based on their findings, investigators concluded that fatigue loading initiated a crack in the universal joint that progressed with time and that the final fracture occurred due to bending tensile overload.