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Engineering Fracture Mechanics

Engineering Fracture Mechanics. Instructor: Prof. K. Ramesh, Department of Applied Mechanics, IIT Madras. The course covers the basic aspects of Engineering Fracture Mechanics. Topics covered in this course include: Spectacular failures that triggered the birth of fracture mechanics, Modes of loading, Classification as LEFM and EPFM, Crack growth and fracture mechanisms, Energy release rate, Resistance, Griffith Theory of fracture, Extension of Griffith Theory by Irwin and Orowan, R-Curve, Pop-in phenomena, Crack branching. Necessary and sufficient conditions for fracture, Stress and Displacement fields in the very near and near-tip fields, Westergaard, Williams and Generalised Westergaard solutions, Influence of the T-stress and higher order terms, Role of photoelasticity on the development of stress field equations in fracture mechanics, Equivalence between SIF and G, Various methods for evaluating Stress Intensity Factors, Modeling plastic zone at the crack-tip, Irwin and Dugdale models, Fracture toughness testing, Fedderson TMs residual strength diagram, Paris law, J-integral, HRR field, Mixed-mode fracture, Crack arrest methodologies. (from nptel.ac.in)

Lecture 28 - Modeling of Plastic Deformation

Empirical relations of Newman and Raju - continued, Triaxiality at the crack-tip - pictorial explanation, Selection of fracture toughness for various types of cracks, Insights of SIF for various cracks, Principal stresses at the crack-tip, Triaxiality - mathematical definition, Simplistic model to get plastic zone length and shape for Mode-I using Tresca and von Mises yield criteria.


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Overview of Engineering Fracture Mechanics
Lecture 01 - Course Introduction
Lecture 02 - Spectacular Failures
Lecture 03 - Lessons from Spectacular Failures
Lecture 04 - Linear Elastic Fracture Mechanics and Elasto-Plastic Fracture Mechanics
Lecture 05 - Fracture Mechanics is Holistic
Lecture 06 - Fatigue Crack Growth Model
Lecture 07 - Crack Growth and Fracture Mechanisms
Energy Release Rate
Lecture 08 - Elastic Strain Energy
Lecture 09 - Fracture Strength by Griffith
Lecture 10 - Energy Release Rate
Lecture 11 - Utility of Energy Release Rate
Lecture 12 - Pop-in Phenomenon
Review of Theory of Elasticity
Lecture 13 - Displacement and Stress Formulations
Lecture 14 - Forms of Stress Functions
Crack-tip Stress and Displacement Fields
Lecture 15 - Airy's Stress Function for Mode-I
Lecture 16 - Westergaard Solution of Stress Field for Mode-I
Lecture 17 - Displacement Field for Mode-I
Lecture 18 - Relation between K_I and G_I
Lecture 19 - Stress Field in Mode-II
Lecture 20 - Generalized Westergaard Approach
Lecture 21 - William's Eigenfunction Approach
Lecture 22 - Multi-parameter Stress Field Equations
Lecture 23 - Validation of Multi-parameter Field Equations
Discussion Section - I
Lecture 24 - Discussion Section - I
Stress Intensity Factor (SIF), Plastic Zone Modeling, Fracture Toughness Testing
Lecture 25 - Evaluation of SIF for Various Geometries
Lecture 26 - SIF for Embedded Cracks
Lecture 27 - SIF for Surface Cracks
Lecture 28 - Modeling of Plastic Deformation
Lecture 29 - Irwin's Model
Lecture 30 - Dugdale Model
Lecture 31 - Fracture Toughness Testing
Lecture 32 - Plane Strain Fracture Toughness Testing
Lecture 33 - Plane Stress Fracture Toughness Testing
Crack Initiation and Life Estimation
Lecture 34 - Paris Law and Sigmoidal Curve
Lecture 35 - Crack Closure
Lecture 36 - Crack Growth Models
Advanced Topics
Lecture 37 - J-Integral
Lecture 38 - HRR (Hutchinson, Rice and Rosenfield) Field and CTOD
Lecture 39 - Failure Assessment Diagram and Mixed Mode Fracture
Lecture 40 - Crack Arrest and Repair Methodologies
Discussion Section-II
Lecture 41 - Discussion Section-II