3.35 | Fall 2003 | Graduate

Fracture and Fatigue

Calendar

SES # TOPICS
1 Introduction

  • Fracture and fatigue of bulk materials, thin films and surfaces
  • Macroscopic failure modes
  • Microscopic failure modes
Part I: FRACTURE
2-3 Mechanics of Fracture

  • Energy release rate and crack driving force
  • Linear elastic fracture mechanics
  • Elastic-plastic fracture mechanics
  • Resistance curves
  • Measurement matters and ASTM standards
4-5 Micromechanisms of Fracture

  • Ductile failure
  • Transitions in fracture modes
  • Stress-based criteria
  • Strain-based criteria
  • Energy-based criteria
6-7 Microstructural Effects

  • Ferrous alloys
  • Aluminum alloys
  • Matrix failure versus grain boundary fracture
  • Damage processes in ceramics and polymers
  • Thin films and surface coatings
8 Interface Fracture Mechanics and Toughness Locus

  • Elasticity aspects
  • Plasticity aspects
9 Toughening Mechanisms

  • Deflection toughening
  • Process zone toughening
  • Ligament toughening
  • Interfacial toughening
10 Fracture Mechanisms in Polymers

  • Crazing
  • Shear localization
  • Rubber toughening
11 Thin Films, Coatings and Layered Materials

  • Thermal residual stresses
  • Fracture mechanisms
  • Compositionally graded structural and thin-film layers
12 Practical Considerations

  • Design
  • Case studies
13 EXAM 1
Part II: FATIGUE
14 Overview

  • Historical background
  • Different approaches to fatigue
15 Micromechanisms of Fatigue Crack Initiation in Ductile and Brittle Solids

  • Cyclic hardening and evolution of dislocation patterns
  • Persistent slip bands and surface roughening
  • Slip-based models for fatigue crack initiation
  • Crack initiation in commercial materials, ceramics and polymers
16 Total-Life Approaches to Fatigue

  • Stress-life approach (S-N curves)
  • Strain-life approaches
  • Concept of damage accumulation
  • Some practical considerations
17 Fatigue Crack Growth in Ductile Metals and Alloys

  • Fracture mechanics characterization
  • Fatigue life calculations
  • Different microscopic and macroscopic stages of fatigue crack growth
  • Models of formation of ductile striations and crack growth
18 Fatigue Crack Growth in Brittle Solids

  • Constitutive models for cyclic deformation in ceramics
  • Room and high-fatigue crack growth in ceramics
19 Fatigue Crack Growth in Polymeric Materials

  • Cyclic deformation characteristics
  • Micromechanisms of fatigue crack growth
  • Microscopic “signature” due to crazing and shear banding
20 Mechanisms of Fatigue Crack Growth Retardation

  • Different types of crack closure (experiments, analyses and numerical simulations)
  • Fatigue crack deflection (models and microstructural examples)
  • Crack-tip versus crack-wake effects
  • Crack retardation following tensile overloads
21 Corrosion Fatigue and Creep Fatigue

  • Effect of environments
  • Fracture mechanics characterization of creep fatigue
  • Case study of failure in power generation equipment, autovalves
22 Fatigue at Interfaces

  • Fatigue fracture parallel to a bimaterial interface
  • Fatigue fracture normal to a bimaterial interface
  • Fatigue of coatings
  • Thermomechanical fatigue of coated and layered materials
23-24 Case Studies

  • 1985 Japan Airlines Plane Crash
  • Failure analysis of a total-hip and knee replacement component
  • Failure of laser-linked metal interconnects in microelectronics
  • Critical issues in the failure of mechanical heart valves
  • Fatigue failure in turbogenerators
25 EXAM 2

Course Info

Instructor
As Taught In
Fall 2003
Level
Learning Resource Types
Lecture Notes
Problem Sets with Solutions