Lifetime Estimation of Welded Joints (eBook)

Tadeusz Lagoda (Autor)

eBook Download: PDF

2008
X, 118 Seiten
Springer Berlin (Verlag)
978-3-540-77062-6 (ISBN)

Infos

In the paper the author attempts to assess the fatigue life of chosen welded joints. It focuses especially on chosen problems that accompany deter- nation of the fatigue life of welded joints, taking into consideration the strain energy density parameter. Chapter 2 describes the welded joint as a stress concentrator. The state of stress and strain in the notch are described and theoretical and fatigue coefficients are indicated. The fatigue coef- cient of the notch effect is estimated on the basis of fictitious radius in the notch root. Chapter 3 presents a model of fatigue life assessment under uniaxial stress state with statistical handling of data presented. The new energy model of fatigue life assessment, which rests upon the analysis of stress and strain in the critical plane, is described in detail in chapter 4. The principle of such a description is presented in the uniaxial as well as in - axial state of loading. Chapter 5 contains the analysis of tests of four ma- rials subjected to different loadings: cyclic, variable-amplitude with Ga- sian distribution, and variable amplitude with Gaussian distribution and overloading for symmetric and pulsating loading. The analysis is based on the determined fatigue characteristics for all the considered materials. Chapter 6 shows the application of the model in the fatigue life assessment in the complex state of loading (bending with torsion of flange-tube and tube-tube joints) based on fatigue research of steel and aluminum welded joints carried out in well-known German centres.

Inhalt

Preface 5
Contents 7
Notation 9
1 Introduction 11
2 Welded Joints as the Stress Concentrator 15
2.1 The Complex Stress State in the Notch 15
2.2 Theoretical Notch Coefficient 18
2.3 The Fatigue Notch Coefficient 20
2.4 The Fictitious Radius of the Welding Notch 22
2.5 The Notch Coefficient with the Use of the Fictitious Notch Radius 25
3 The Stress Model for the Assessment of Fatigue Life Under Uniaxial Loading 26
3.1 Algorithm for the Assessment of Fatigue Life Under Uniaxial Loading State 26
3.2 Statistic Evaluation 36
4 The Energy Model of Fatigue Life Assessment 41
4.1 The Energy Parameter Under Uniaxial Loading 41
4.2 The Energy Parameter Under Multiaxial Loading 47
4.2.1 The Generalized Criterion of the Parameter of Normal and Shear Strain Energy Density Parameter in the Critical Plane 48
4.2.2 The Criterion of Maximum Parameter of Shear and Normal Strain Energy Density on the Critical Plane Determined by the Normal Strain Energy Density Parameter 50
4.2.3 The Criterion of Maximum Parameter of Shear and Normal Strain Energy Density in the Critical Plane Determined by the Shear Strain Energy Density Parameter 51
4.3 Algorithm for Fatigue Life Assessment 55
5 An Example of Fatigue Life Evaluation Under Simple Loading 67
5.1 Fatigue Tests 67
5.1.1 Tests Under Constant-amplitude Loading 70
5.1.2 Tests Under Variable-amplitude Loading 74
5.2 Verification of the Results Obtained Under Variable-amplitude Loading 75
6 An Example of Fatigue Life Evaluation Under Complex Loading States 78
6.1 Fatigue Tests 78
6.2 Verification of the Criteria Under Constant-amplitude Loading 87
6.2.1 The Parameter of Shear and Normal Strain Energy Density on the Critical Plane Determined by the Parameter of Normal Strain Energy Density 87
6.2.2 The Parameter of Shear and Normal Strain Energy Density in the Critical Plane Determined by the Shear Strain Energy Density Parameter 93
6.2.3 The Influence of Different Frequencies of Bending and Torsion on Fatigue Life 98
6.3 Verification Under Variable-amplitude Loading 99
7 Conclusions 102
References 104
Summary 123

Produkt-Details

• Erscheint lt. Verlag: 10.1.2008
• Zusatzinfo: X, 118 p.
• Verlagsort: Berlin
• Sprache: englisch
• Themenwelt: Mathematik / Informatik ► Mathematik ► Statistik
• Themenwelt: Mathematik / Informatik ► Mathematik ► Wahrscheinlichkeit / Kombinatorik
• Themenwelt: Naturwissenschaften ► Physik / Astronomie
• Themenwelt: Technik ► Maschinenbau
• Themenwelt: Wirtschaft ► Betriebswirtschaft / Management
• Schlagworte: fatigue • joints • life time assessment • Materials • Quality Control, Reliability, Safety and Risk • stain • Stress • Torsion • uniaxial load
• ISBN-10: 3-540-77062-3 / 3540770623
• ISBN-13: 978-3-540-77062-6 / 9783540770626