Fracture Mechanics (Virtual Classroom)

Topics Covered

• Introduction – Lecture, video, and discussion
  • Video: “The Last of the Liberties”, which documents the brittle fracture of the Liberty Ships in WW II and the resulting birth of fracture mechanics as an engineering discipline.
  • Fracture mechanics versus strength-of-materials approach to design against fracture
  • Fracture mechanics versus S-N curve approach to design against fatigue failure
• Linear elastic fracture mechanics (LEFM) – Lecture, discussion, and examples
  • The Griffith model for cracks
  • The energy release rate parameter
  • The stress intensity factor (K)
  • Crack tip similitude
  • Crack tip plasticity
  • K_Ic testing
• Elastic-plastic fracture mechanics – Lecture, discussion, and examples
  • Crack tip opening displacement (CTOD) parameter
  • J-integral parameter
  • J_Ic and J resistance curve testing
  • Similitude under elastic-plastic conditions
• Introduction to fatigue crack growth – Lecture, discussion, and examples
  • Similitude in fatigue
  • Empirical crack growth equations
  • Life prediction by numerical integration
  • Using crack growth analysis to define inspection intervals
• Advanced topics in fatigue – Lecture, discussion, and examples
  • Crack closure
  • Linear damage model for variable-amplitude loading
  • Retardation and load interaction
  • Growth of small cracks
• Environmental cracking – Lecture, discussion, and examples
  • Basic principles and terminology in corrosion engineering
  • Stress corrosion cracking (SCC)
  • Hydrogen embrittlement
  • Corrosion fatigue
  • Laboratory testing
• LEFM Applications – Lecture, discussion, and examples
  • The principle of superposition
  • Computing stress intensity factor for polynomial stress gradients
  • The weight function method for arbitrary stress gradients
• Elastic-plastic applications – Lecture, discussion, and examples
  • The EPRI J estimation handbook
  • Ductile instability
  • The failure assessment diagram (FAD) method
  • Incorporating weld residual stresses into the FAD method
  • Monte Carlo probabilistic analysis
• Finite element analysis of components with cracks – Lecture, discussion, and examples
  • Incorporating a crack into a finite element mesh
  • Comparison of methods to compute KI
  • Modeling crack growth with finite element analysis
• Fracture mechanisms in metals & alloys – Lecture, discussion, and examples
  • Ductile fracture (microvoid coalescence)
  • Cleavage fracture
  • The ductile-brittle transition region
  • Intergranular fracture
• General discussion and course wrap-up