Machine Design : Theories of failure and Design for fatigue

Machine design is the practice of designing structural elements of a product to meet functional and durability criteria .

Failure prevention is a big part of study for Machine design . This course deals with the various theories of failure in Static and dynamic (cyclic) loading conditions.

• Basics of Principal stress from mechanics of materials

• Importance of principal stress

• What are Theories of failure? the most simplest form

• Maximum Shear stress Theory - How it is derived , the analysis and cases

• Maximum distortion Energy theory - the most widely used theory of failure for ductile materials

  • The derivation from concept of strain energy

  • Definition of Von mises stress

• Mohr theory - Theory for materials with different tensile and compressive strengths

• Coulomb- Mohr theory

• Brittle Failure theory

• Selection of Failure theory

• What is Fatigue loading? fatigue failure?

• Fracture mechanics basics

• What is fracture toughness property

• Factors to be considered

• The S-N curve and RR Moore test to develop S-N curve

• Endurance strength and Endurance limit

• The Endurance limit modifying factors

  • Surface, Size, temperature, loading

• Stress concentration factor

• Characterization of cyclical loading

• Definition of failure criteria in Fatigue

The course is designed to be compact and to the point highlighting the most important concepts and the Why ? behind it.

This is an advanced level course suitable if you are already familiar with strength of materials or mechanics of materials and basics of mechanical engineering .