Mechanical Failure: temperature, stress, cyclic and loading effect

ISSUES TO ADDRESS...

• How do cracks that lead to failure form?
• How is fracture resistance quantified? How do the fracture
  resistances of the different material classes compare?
• How do we estimate the stress to fracture?
• How do loading rate, loading history, and temperature
  affect the failure behavior of materials?

Content:

• Fracture, Fatigue and Creep
• Fracture mechanisms: Ductile vs Brittle Failure
• Stress-Strain Behavior versus Temperature
• Charpy Impact Testing
• Charpy V-Notch Impact Data: Energy vs Temperature
• Famous example failures: Liberty ships
• Ductile Fracture: distinctive features on macro and micro levels
• Fracture Surface under Tensile and Shear load
• Brittle Fracture Surface
• Brittleness of Ceramics
• Porosity and Temperature Effects in Ceramics
• Nucleation and Propagation Of Cracks in Ceramics
• Crazing during Fracture of Thermoplastic Polymers
• Ideal versus Real Behavior
• Flaws are Stress Concentrators!
• Concentration of Stress at Crack Tip
• Modes of Fracture which Operate on Cracks
• Griffith’s Criteria for Fracture and Failure
• Fatigue: Failure from cyclic stress
• S-N Curves Failure
• Fatigue Behavior of Polymers
• Fatigue Mechanisms
• Improving Fatigue Life
• Anelastic Effects
• Creep Failure and Secondary Creep
• Creep RECOVERY and Vacancy-assisted Climb
• Major recover mechanism is non-conservative climb
• Design Examples, Design Strategy, Case Studies
• SUMMARY

Researchers should cite this work as follows:

• Duane Douglas Johnson; Omar N Sobh (2009), "Illinois MatSE 280 Introduction to Engineering Materials, Lecture 9: Mechanical Failures," http://nanohub.org/resources/6108.

  BibTex | EndNote

1. course lecture
2. Illinois
3. material properties
4. materials
5. material science