Multiaxial Notch Fracture and Fatigue

Description

This book presents the unified fatigue life prediction equation for low/medium/high cycle fatigue of metallic materials relevant to plain materials and notched components. The unified fatigue life prediction equation is the Wöhler equation, in which the "stress-based intensity parameter" is calculated based on the linear-elastic analysis. A local approach for the static fracture analysis for notched components is presented based on the notch linear-elastic stress field. In the local approach, a stress intensity parameter is taken as a stress-based intensity parameter. Experimental verifications show that the local approach is also suited for the static fracture analysis for notched components made of ductile materials. The book is also concerned with a material failure problem under the multiaxial stress states. A concept of the material intensity parameter is introduced in this book. It is a material property parameter that depends on both Mode-I fracture toughness and Mode-II (or Mode-III) fracture toughness and the multiaxial parameter to characterize the variation of the material failure resistance (notch fracture toughness) with the multiaxial stresses states. The failure condition to assess mixed-mode fracture of notched (or cracked) components is stated as the stress-based intensity parameter being equal to the material intensity parameter. With respect to the traditional S-N equation, a similar S-N equation is presented and verified to have high accuracy. This book will be of interest to professionals in the field of fatigue and fracture for both brittle and ductile materials. Cover Half Title Title Copyright Contents Preface Author List of Abbreviations Chapter 1 Introduction 1.1 A Brief Description of the Multiaxial Fatigue Limit Equation 1.2 An Extension of the Multiaxial Fatigue Limit Equation to Mixed Mode Cracks 1.3 An Extension of the Multiaxial Fatigue Limit Equation to Mode I/III V-Notches 1.4 An Extension of the Multiaxial Fatigue Limit Equation to Mode I/III Rounded V-Notches 1.5 Three Comments on the Empirical Failure Equation 1.6 A Comment on the Unified Prediction Equation for a Low/Medium/High Cycle Fatigue of Metallic Materials (From Plain Materials to Notched Materials) References Appendix A: A Practicability of Establishing the Unified Prediction Equation for a Low/Medium/High Cycle Fatigue of Metallic Materials Chapter 2 Applicability of the Wöhler Curve Method for a Low/Medium/High Cycle Fatigue of Metallic Materials 2.1 Introduction 2.2 Practicability of the Wöhler Curve Method for a Low-Cycle Fatigue of Metallic Materials 2.2.1 A Description on the Practicability of the Wöhler Curve Method for a Low-Cycle Fatigue of Metallic Materials 2.2.2 Experimental Verifications 2.2.3 A Comment on This Section 2.3 Applicability of the Wöhler Curve Method for a Low/Medium/High Cycle Fatigue of Metallic Materials 2.3.1 A Proper Mechanical Quantity in the Fatigue Life Prediction Equation 2.3.2 Multiaxial Fatigue Life Prediction Equation 2.4 Experimental Verifications and Discussions 2.5 Conclusions and Final Comments References Appendix A: Experimental Investigations: The Wöhler Curve Method Is Well Suited for the Low-Cycle Fatigue Life Analysis of Metallic Materials by the Low-Cycle Fatigue Test Data of Metallic Materials from the Literature Appendix B: Experimental Investigations: The Wöhler Curve Method Is Well Suited for the Low-Cycle Fatigue Life Analysis of Metallic Materials by Basquin’s Curve in the Strain-Life Curve Figure of Metallic Material from the Literature Appendix C: Experimental Investigations: The Wöhler Curve Method Is Well Suited for Fatigue Life Assessment of a Low/Medium/High Cycle Fatigue of Metallic Materials by Strain Control Experimental Fatigue Data from the Literature Chapter 3 Notch S-N Equation for a Low/Medium/High Cycle Fatigue of Metallic Materials 3.1 Introduction 3.2 A Brief Description of the Unified Lifetime Estimation Equation of a Low/Medium/High Cycle Fatigue of Metallic Materials 3.2.1 A Description of the Practicability of the Wöhler Curve Method for a Low-Cycle Fatigue of Metallic Materials 3.2.2 The Unified Lifetime Estimation Equation of a Low/Medium/High Cycle Fatigue of Metallic Materials 3.3 S-N Equation of Notch Specimens 3.3.1 A Brief Description of a Linear Elastic Notch Stress Field 3.3.2 Notch S-N Equation Under Mode I Loading 3.3.3 Notch S-N Equation Under Mode III Loading 3.3.4 Notch S-N Equation Under Mode I/III Loading 3.4 Experimental Verifications and Discussions 3.5 Application of Notch S-N Equation in Multiaxial Fatigue Limit Analysis of Notched Components 3.6 Conclusions and Final Comments References Appendix A: On Dealing with Nonproportional Loading Fatigue Appendix B: Multiaxial Fatigue Life Prediction Equation with Nonzero Mean Stress Appendix C: Experimental Investigations: The Inherent Notch S-N Equations Are Used to Perform the Fatigue Life Assessment of Notched Components Appendix D: Experimental Investigations: The Notch S-N Equation Is Verified to Be Naturally Existing by Some Fatigue Test Data of Various Notch Specimens from the Literature Chapter 4 A Local Approach for Fracture Analysis of V-Notch Specimens Under Mode I Loading 4.1 Introduction 4.2 A Brief Description of Linear Elastic Stress Field and Stress Intensity of the V-Notches 4.3 A Local Stress Field Failure Model 4.4 Experimental Verifications 4.5 Conclusions and Final Comments References Appendix A: The Practicability of Establishing the Unified Prediction Equation for a Low/Medium/High Cycle Fatigue of Metallic Materials Chapter 5 A Local Stress Field Failure Model for Sharp Notches 5.1 Introduction Part 1 5.2 A Brief Description of Local Stress Field Ahead of Rounded V-Notches 5.3 A Local Stress Field Failure Model 5.4 A Concept of the Stress Concentration Factor Eigenvalue k* 5.4.1 On the Existence of k* (or ρ*) 5.4.2 An Approach to Determining k* 5.5 Experimental Verifications 5.6 Conclusions of Part 1 Part 2 5.7 Effect of Notch Angles on k* 5.7.1 A Model of the Effect of Notch Angles on k* 5.7.2 Experimental Verifications 5.8 Effect of Notch Depth on K* 5.8.1 Notch Depth Model for TPB Notch Specimens and Experimental Verifications 5.8.2 Notch Depth Model for SEN Notch Specimens and Experimental Verifications 5.8.3 Notch Depth Model for DEN Notch Specimens and Experimental Verifications 5.8.4 Notch Depth Model for RNT Notch Specimens and Experimental Verifications 5.9 Effect of Different Materials on k* 5.10 Comments of Part 2 Part 3 5.11 An Empirical Equation for Predicting the Fracture Toughness KIc 5.12 Fracture Analysis of Center Notch Plates Made of Metal Materials 5.13 Concluding Remarks References Appendix A: A Local Stress Field Failure Model of Sharp Notches Under III Loading Appendix B: Fatigue Limit Analysis of Notched Components Appendix C: A Local Approach for Fatigue Life Analysis of Notched Components Chapter 6 An Empirical Fracture Equation of Mixed Mode Cracks 6.1 Introduction 6.2 An Empirical Fracture Equation of Mixed Mode Cracks 6.2.1 The Multiaxial Fatigue Limit Equation by Liu and Yan 6.2.2 An Empirical Fracture Equation of Mixed Mode Cracks 6.3 An Approach to Determine KIIc 6.4 Experimental Verifications 6.4.1 Experimental Verifications by the Disk Test 6.4.2 Experimental Verifications by the AS4P Test 6.4.3 Experimental Verifications by Circumferentially Notched Cylindrical Rods 6.5 Final Comments References Appendix A: Experimental Investigations: The Empirical Failure Condition Is Well Suited for the Failure Analysis for Plain Materials Appendix B: Experimental Investigations: The Failure Condition Is Well Suited for the Failure Analysis for Cracked Specimens Made of Plastic Materials Appendix C: The Practicability of Establishing the Unified Prediction Equation for a Low/Medium/High Cycle Fatigue of Metallic Materials Chapter 7 An Empirical Failure Equation to Assess Mixed-Mode Fracture of Notched Components 7.1 Introduction 7.2 A Brief Description of the Multiaxial Fatigue Life Equation 7.3 An Extension of the Multiaxial Fatigue Limit Equation to Mode I/III Rounded V-Notches 7.4 Experimental Verifications 7.5 Final Comments References Chapter 8 A New Type of S-N Equation and Its Application to Multiaxial Fatigue Life Prediction 8.1 Introduction 8.2 A Brief Description of a Multiaxial Fatigue Model 8.3 A New Type of S-N Equation 8.4 Experimental Verifications and Discussions 8.5 Concluding Remarks References Index