MEC 4270 - Fatigue and Fracture in Mechanical Design

• Calculate fatigue lifetimes based on 1) stress-life, 2) strain-life or 3) fatigue crack growth models (Paris’ law)
• Apply non-linear stress-strain models to notch strain analysis (Ramberg-Osgood, Neuber’s rule)
• Design components for fatigue lifetime (infinite life or finite life design)
• Select a best solution method for fatigue design problems
• Judge the appropriate application of solution method for a design problem
• Make engineering assumptions as necessary to calculate fatigue lifetimes
• Evaluate engineering assumptions as either conservative, non-conservative, or best-guess
• Apply fracture mechanics principles in the context of fail-safe design
• Apply fracture mechanics principles in the context of doing failure analysis of broken parts
• Apply counting strategies (rainflow) to complex stress-time histories, to calculate expected lifetimes

• Mechanics of materials
• Materials science

• Fatigue life - basic approach for high-cycle or infinite life design: endurance limit, S-N diagrams (stress-life methods), stress concentration factors
• Fatigue life for plastic strain cycling, low cycle fatigue: Ramberg-Osgood equation (non-linear stress-strain relationship), cyclic stress-strain curves and stress-strain loops in fatigue, strain-life diagrams and strain-life equation, notch strain analysis, Neuber’s rule
• Complex 2D and 3D states of stress in fatigue analysis
• Cumulative damage models and cycle counting methods for complex load histories
• Linear elastic fracture mechanics (LEFM): stress intensity factor and plane strain fracture toughness, fatigue crack growth rate (Paris’ law), non-linear fatigue crack growth problems, requiring numerical solutions
• Fail-safe design methodologies for pressure vessels, structural parts, and inspection intervals
• Failure analysis, applying principles of LEFM and fatigue to broken parts