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2020 | Buch

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Mechanical Behavior and Fracture of Engineering Materials

verfasst von: Dr. Jorge Luis González-Velázquez

Verlag: Springer International Publishing

Buchreihe : Structural Integrity

Enthalten in: Springer Professional "Wirtschaft+Technik" , Springer Professional "Technik"

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Über dieses Buch

This book presents the theoretical concepts of stress and strain, as well as the strengthening and fracture mechanisms of engineering materials in an accessible level for non-expert readers, but without losing scientific rigor. This volume fills the gap between the specialized books on mechanical behavior, physical metallurgy and material science and engineering books on strength of materials, structural design and materials failure. Therefore it is intended for college students and practicing engineers that are learning for the first time the mechanical behavior and failure of engineering materials or wish to deepen their understanding on these topics.
The book includes specific topics seldom covered in other books, such as: how to determine a state of stress, the relation between stress definition and mechanical design, or the theory behind the methods included in industrial standards to assess defects or to determine fatigue life. The emphasis is put into the link between scientific knowledge and practical applications, including solved problems of the main topics, such as stress and strain calculation. Mohr's Circle, yield criteria, fracture mechanics, fatigue and creep life prediction. The volume covers both the original findings in the field of mechanical behavior of engineering materials, and the most recent and widely accepted theories and techniques applied to this topic. At the beginning of some selected topics that by the author's judgement are transcendental for this field of study, the prime references are given, as well as a brief biographical semblance of those who were the pioneers or original contributors. Finally, the intention of this book is to be a textbook for undergraduate and graduate courses on Mechanical Behavior, Mechanical Metallurgy and Materials Science, as well as a consulting and/or training material for practicing engineers in industry that deal with mechanical design, materials selection, material processing, structural integrity assessment, and for researchers that incursion for the first time in the topics covered in this book.

Inhaltsverzeichnis

Frontmatter

1. Stress

Abstract

A brief introduction of the field of Mechanical Behavior and Engineering Materials is given at the beginning of this chapter, where the importance of this field of study is emphasized, followed by the scope of continuum mechanics study and the definition of stress. By using these ideas, the mechanical behavior in uniaxial tension and the design of structural components is described. A comprehensive description of the Cauchŷ’s stress tensor is provided along with a simplified procedure to determine the state of stress, illustrated with practical examples, to continue with a full description of the stress transformation methods, both by matrix algebra and the Mohr’s Circle methods. The description of the Tresca and Von Mises yield criteria is given, including solved problems and the use of two-dimension yield maps. The chapter finalizes with a brief introduction to the stress concentration phenomenon.

Jorge Luis González-Velázquez

2. Strain

Abstract

This chapter begins with the definition of strain from the continuum mechanics point of view, the description of the strain tensor and the strain transformation concept; then, the elastic stress strain relations, namely the constitutive equations, are described for both isotropic and anisotropic behavior. Next is the description of plasticity and plastic behavior of metallic materials, including tables of typical mechanical properties of engineering materials, the following topics are the Baushingher effect, the concepts of real stress and real strain, and the plastic stress-strain equations. A brief introduction of the numeric analysis of stress and strain is presented, along with a description of the procedure to perform an analysis of mechanical behavior by the Finite Element Method and a brief description of the experimental methods of electric resistance extensometry and polaroscopy to measure stress and strain. At the end of this chapter an introduction to the hardness concept and the standard methods to measure it is presented.

Jorge Luis González-Velázquez

3. Plastic Deformation Mechanisms

Abstract

This chapter begins with an introduction of the crystalline structure and crystalline defects of solid materials and the definition of hot and cold work. Then, a full description of the dislocation slip mechanism is presented, including an explanation of the direct observation of dislocations by transmission electron microscopy. Based on the preceding ideas, a description of the slip modes and their associated dislocation substructures is given. The chapter concludes with a brief description of the plastic deformation mechanism by twinning.

Jorge Luis González-Velázquez

4. Strengthening Mechanisms

Abstract

This chapter starts with an explanation of the concept of strength in engineering materials to introduce to a detailed description of the most important strengthening mechanism of metallic materials, being: strain, grain boundary, solid solution, second phase and fine particle. These mechanisms are explained accordingly to the dislocation theory and the most important rules, along with the relevant equations such as the Hall-Petch law, the rule of mixtures, the interparticle spacing strengthening relation and so on are introduced. The effects of second phase particle shape and distribution on the mechanical strength of materials is discussed. The upper yield strength and strain aging phenomena are described. Furthermore, the martensite hardening behavior in steels is thoroughly described due to its technological importance.

Jorge Luis González-Velázquez

5. Mechanical Behavior of Composites and Polymers

Abstract

This chapter is divided in two sections; the first section is an introduction to the nature and classification composite materials, followed with a description of the mechanical behavior of fiber reinforced resin matrix composites, including the concepts of critical fiber length and fiber content to achieve functional composites. The modes of composite materials failure are described along with the most accepted equations to predict the strength of uniaxial fiber reinforced composites. The second section of this chapter deals with the mechanical behavior of thermoplastic polymers, describing the concepts of relaxation and glass transformation, a brief description of the Maxwell and Voight models of stress-strain behavior of thermoplastic polymers and a brief description of the mechanical behavior of elastomers. The chapter finishes with an introduction to the main failure mechanisms of polymers.

Jorge Luis González-Velázquez

6. Fracture

Abstract

This chapter presents a comprehensive introduction of the fracture phenomena as the final stage of the mechanical behavior of engineering materials. It begins with the basic concepts of fracture, the classification of fractures from the engineering point of view and a brief description of the static fracture mechanisms, namely cleavage and micro-void growth and coalescence. The chapter continues with an introduction to fracture mechanics, starting with the analysis of cohesive strength and the Griffith analysis of brittle fracture, to continue with the Irwin’s linear elastic fracture mechanic approach, including the concepts of energy release rate, the R-Curve, the stress intensity factor, and fracture toughness, and finishing with an explanation of the Rice’s nonlinear fracture mechanics J-Integral and the Wells’ CTOD analysis. The previous ideas are used to present an introduction the fundamentals of structural integrity analysis. The final section of this chapter explains the significance and practical aspects of the Charpy impact test.

Jorge Luis González-Velázquez

7. Fatigue

Abstract

This chapter presents a thoroughly description of the fatigue phenomena in engineering materials, starting with an historical synopsis of fatigue failures, the Wöler’s concept of fatigue life and a description of the S-N curves. A brief description of the fractographic characteristics of fatigue fracture surfaces and mechanisms is given. The central part of this chapter presents the mechanical methods of fatigue characterization, describes the factors that affect fatigue endurance and explain the most widely accepted methods to estimate the fatigue life of structural components, including the Haigh’s diagram, the Weibull’s statistical analysis, the Miner’s rule and the Manson and Coffin Universal Slopes Method. The fatigue crack growth behavior and the Paris’ law are described at the end of the chapter.

Jorge Luis González-Velázquez

8. High Temperature Mechanical Behavior

Abstract

This chapter starts with the description of the effects of elevated temperature on the deformation characteristics of materials by means of the Stress-Rupture and the Constant-Stress creep curves. The Creep Power Law for secondary creep is introduced along with the Larson and Miner creep life prediction method. Further, the deformation mechanisms in creep are described, as well as the creep fracture mechanism. Then, the ideas are applied to explain the foundations for the development of high-temperature service materials, known as refractory. The chapter ends with a brief description of the superplastic behavior that results of the combination of strengthening mechanism and high temperature behavior.

Jorge Luis González-Velázquez

Titel: Mechanical Behavior and Fracture of Engineering Materials
verfasst von: Dr. Jorge Luis González-Velázquez
Verlag: Springer International Publishing
Electronic ISBN: 978-3-030-29241-6
Print ISBN: 978-3-030-29240-9
DOI: https://doi.org/10.1007/978-3-030-29241-6

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