Mechanical Testing and Evaluation
At least three major trends have occurred since the last edition of Volume 8 in 1984. First, concurrent engineering is growing in importance in the industrial world, and mechanical testing plays a major role in concurrent engineering through the measurement of properties of product design, as well as for deformation processing. ASM Handbook, Volume 20, Materials Selection and Design (1997) reflects this focus in concurrent engineering and the broadening spectrum of involvement of materials engineers. Second, new methods of measurement have evolved such as strain measurement by vision systems and ultrasonic methods for measurement of elastic properties. This area will continue to grow as miniaturized sensors and computer vision technologies mature. Third, computer modeling capabilities, based on fundamental continuum principles and numerical methods, have entered the mainstream of everyday engineering. The validity of these computer models depends heavily on the availability of accurate material properties from mechanical testing.
Toward this end, this revision of ASM Handbook, Volume 8 is intended to provide up-to-date, practical information on mechanical testing for metals, plastics, ceramics, and composites. The first section, “Introduction to Mechanical Testing and Evaluation,” covers the basics of mechanical behavior of engineering materials and general engineering aspects of mechanical testing including coverage on the accreditation of testing laboratories, mechanical tests in metalworking operations, and the general mecahnical tests of plastics and ceramics. The next three sections are organized around the basic modes of loading of materials: tension, compression bending, shear, and contact loads. The first four modes (tension, compression, bending, and shear) are the basic simple loading types for deterimation of bulk properties of materials under quasi-statis or dynamic conditions.
The third section, “Hardness Testing,” describes the various methods for indentation tesitng, which is a relatively inexpensive test of great importance in manufacturing quality control and materials science. This section includes new coverage on instrumented (nano-indentation) hardness testing and the special issues of hardness testing of ceramics. Following the section on hardness testing, the fourth section addresses the mechanical evaulation of surfaces in terms of adhesion and wear characteristics from point loading and contact loading. These methods, often in conjunction with hardness tests, are used to determine the response of surfaces and coatings to mechanical loads.
The next four sections cover mechanical testing under important dynamic conditions of slow strain rates (i.e., creep deformation and stress relaxation), high strain rate testing, dynamic fracture, and fatigue. These four sections cover the nuances of testing materials under the basic loading types but with the added dimension of time as a factor. Very long-term, slow rate of loading (or unloading) in creep and stress relaxation is a key factor in many high-temperature applications and the testing of viscoelastic materials. On the opposite end of the spectrum, high strain rate testing characterizes material response during high-speed deformation processes and dynamic loading of products. Fracture toughness and fatigue testing are the remaining two sections covering engineering dynamic properties. These sections include coverage on the complex effects of temperature and environmental degradation on crack growth under cyclic or sustained loads.
Finally, the last section focuses on mechanical testing of some common types of engineering components such as gears, bearings, welds, adhesive joints, and mechanical fasteners. A detailed article on residual stress measurements is included, as residual stress from manufacturing operations can be a key factor in some forms of mechanical performance such as stress corrosion cracking and fatigue life analysis. Coverage of fiber-reinforced composites is also included as a special product form with many special and unique testing and evaluation requirements.
In this extensive revision, the end result is over 50 new articles and an all-new Volume 8 of the ASM Handbook series. As before, the key purpose of this Handbook volume is to explain test set-up, common testing problems and solutions, and data interpretations so that reasonably knowledgeable, but inexperienced, engineers can understand the factors that influence proper implementation and interpretation. Easily obtainable and recognizable standards and research publications are referenced within each article, but every attempt is made to provide sufficient clarification so that inexperienced readers can understand the reasons and proper interpretation of published industrial test standards and research publications.
In this effort, we greatly appreciate the knowledgeable guidance and support of all the section editors in developing content requirements and author recommendations. This new content would not have been possible without their help: Peter Blau, Oak Ridge National Laboratory; James C. Earthman, University of California, Irvine; Brian Klotz, General Motors Corporation; Peter K. Liaw, University of Tennessee; Sia Nemat-Nasser, University of California, San Diego; Todd M. Osman, U.S. Steel Research; Gopal Revankar, Deere & Company; Robert Ritchie, University of California at Berkeley. Finally, we are all especially indebted to the volunteer spirit and devotion of all the authors, who have given us their time and effort in putting their expertise and knowledge on paper for the benefit of others. This work would not have been possible without them.
Concurrent Technologies Corporation
The Timken Company