Mechanical tests are performed to evaluate the durability of gears under load. The chapter first discusses the processes involved in the computations of stress for test parameters of gear. Next, the chapter reviews the four areas of specimen characterization of a test program, namely dimensional, surface finish texture, metallurgical, and residual stress. The following section presents the tests that simulate gear action, namely the rolling contact fatigue test, the single-tooth fatigue test, the single-tooth single-overload test, and the single-tooth impact test. Finally, the chapter describes the test procedures for surface durability (pitting), root strength (bending), and scoring (or scuffing) testing.

This chapter discusses composite testing procedures, including tension, compression, shear, flexure, and fracture toughness testing as well as adhesive shear, peel, and honeycomb flatwise tension testing. It also discusses specimen preparation, environmental conditioning, and data analysis.

This article briefly introduces some commonly used methods of mechanical testing of plastics for determining mechanical properties, also describing the test methods and providing comparative data for the mechanical property tests. In addition, creep testing and dynamic mechanical analyses of viscoelastic plastics are briefly described. The discussion covers the most commonly used tests for impact performance, various types of hardness test for plastics, the fatigue strength of viscoelastic materials, and the tension testing of elastomers and fibers.

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 factors that govern the mechanical properties of titanium, beginning with the morphology of the alpha phase. It explains that the shape of the alpha phase has a significant effect on many properties, including hardness, tensile strength, toughness, and ductility as well as creep, fatigue strength, and fatigue crack growth rate. It also discusses the influence of other titanium phases and the properties of titanium-based intermetallic compounds, metal-matrix composites, and shape-memory alloys.

This appendix provides readers with worked solutions to 25 problems involving calculations associated with tensile testing and the determination of mechanical properties and variables. The problems deal with engineering factors and considerations such as stress and strain, loading force, sample lengthening, and machine stiffness, and with mechanical properties and parameters such as elastic modulus, Young’s modulus, strength coefficient, strain-hardening exponent, and modulus of resilience. They also cover a wide range of materials including various grades of aluminum and steel as well as iron, titanium, brass, and copper alloys.

This chapter discusses the techniques applicable to the diagnosis of corrosion failures, including visual and microscopic examination of corroded surfaces and microstructure; chemical analysis of the metal, corrosion products, and bulk environment; nondestructive evaluation methods; corrosion testing techniques; and mechanical testing techniques. A guide to investigative techniques used in corrosion failure analysis is provided in a table, describing the advantages and limitations of each technique. The principal stages of the investigation and analysis of corrosion failures discussed in the chapter are: collection of background information and sampling; preliminary laboratory examination; detailed metallographic and fractographic examinations; chemical analysis of corrosion products and bulk materials; corrosion testing for quality control; mechanical testing for quality control; and analysis of results and report writing.

This chapter provides an overview of the possible mechanisms of failure for heat treated steel components and discusses the techniques for examining fractures, ductile and brittle failures, intergranular failure mechanisms, and fatigue. It begins with a description of the general sources of component failure. This is followed by a section on the stages of a failure analysis, which can proceed one after the other or occur at the same time. These stages of analysis are collection of background data, preliminary visual examination, nondestructive testing, selection and preservation of specimens, mechanical testing, macroexamination, microexamination, metallographic examination, determination of the fracture mechanism, chemical analysis, exemplar testing, and analysis and writing the report. The chapter ends with a discussion on various processes involved in the determination of the fracture mechanism.

Fabricated powder metallurgy (P/M) parts are evaluated and tested at several stages during manufacturing for part acceptance and process control. The various types of tests included are dimensional evaluation, density measurements, hardness testing, mechanical testing, and nondestructive testing. This chapter is a detailed account of these testing methods. It describes the four most common types of defects in P/M parts, namely ejection cracks, density variations, microlaminations, and poor sintering. The chapter discusses the capabilities and limitations of various nondestructive evaluation methods to flaw detection in P/M parts. The nondestructive evaluation methods covered are mechanical proof testing, metallography, liquid penetrant crack detection, filtered particle crack detection, magnetic particle crack inspection, direct current resistivity testing, x-ray radiography, computed tomography, gamma-ray density determination, and ultrasonic techniques.

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 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 reviews the causes and cases associated with the problems originated by tempering of steels. To provide background on this phenomenon, a brief description of the martensite reactions and the steel heat treatment of tempering is given to review the different stages of microstructural transformation. A section describing the types of embrittlement from tempering, along with mechanical tests for the determination of temper embrittlement (TE), is presented. Various factors involved in the interaction of the TE phenomenon with hydrogen embrittlement and liquid-metal embrittlement are also provided. The cases covered are grinding cracks on steel cam shaft and transgranular and intergranular crack path in commercial steels.

This chapter is a detailed account of the tensile testing procedure used for evaluating metals and alloys. The discussion covers the stress-strain behavior of metals determined by tensile testing, properties determined from testing, test machines for measuring mechanical properties, and general procedures of tensile testing. Three distinct aspects of standard test methods for tension testing of metallic materials are discussed: test piece preparation, geometry, and material condition; test setup and equipment; and test procedure.

The mechanical behavior of a material is its response to an applied load or force. Important mechanical properties are strength, hardness, stiffness, and ductility. This chapter discusses three principal ways in which these properties are tested: tension, compression, and shear. Important tensile properties that can be determined by the tensile test include yield strength, ultimate tensile strength, ductility, resilience, and toughness. The chapter describes the effects of stress concentrations on ductile metals under cyclic loads. Other topics covered include combined stresses, yield criteria, and residual stresses of metals.

This chapter discusses the basic steps of a failure investigation. It explains that the first step is to gather and document information about the failed component and its operating history. It advises investigators to visit the failure site as soon as possible to record damages and collect test specimens for subsequent examination and chemical analysis. It also discusses the role of mechanical property testing, the use of nondestructive evaluation, and the final step of generating a report.

This chapter discusses the operating mechanism, applications, advantages, and limitations of Brinell hardness testing, Rockwell hardness testing, Vickers hardness testing, Scleroscope hardness testing, and microhardness testing. In addition, the general precautions and selection criteria to be considered are described and details of equipment setup provided.

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.

Product design requires an understanding of the mechanical properties of materials, much of which is based on tensile testing. This chapter describes how tensile tests are conducted and how to extract useful information from measurement data. It begins with a review of the different types of test equipment used and how they compare in terms of loading force, displacement rate, accuracy, and allowable sample sizes. It then discusses the various ways tensile measurements are plotted and presents examples of each method. It examines a typical load-displacement curve as well as engineering and true stress-strain curves, calling attention to certain points and features and what they reveal about the test sample and, in some cases, the cause of the behavior observed. It explains, for example, why some materials exhibit discontinuous yielding while others do not, and in such cases, how to determine when yielding begins. It also explains how to determine other properties via tensile tests, including ductility, toughness, and modulus of resilience.

Instrumented indentation hardness testing significantly expands on the capabilities of traditional hardness testing. It employs high-resolution instrumentation to continuously control and monitor the loads and displacements of an indenter as it is driven into and withdrawn from a material. The scope of application comprises displacements even smaller than 200 nm (nano range) and forces even up to 30 kN . Mechanical properties are derived from the indentation load-displacement data obtained in simple tests. The chapter presents the elements of contact mechanics that are important for the application of the instrumented indentation test. The test method according to the international standard (ISO 14577) is discussed, and this information is supplemented by information about the testing technique and some example applications. The chapter concludes with a discussion on the extensions of the standard that are expected in the future (estimation of the measurement uncertainty and procedures for the determination of true stress-strain curves).

This article focuses on friction and wear as they relate to polymeric materials, covering friction and wear applications for polymeric materials. The discussion covers the causes and mechanisms of friction, wear, and lubrication; different test methods developed to simulate friction and wear mechanisms; and friction and wear test data used for polymeric materials.