Fracture of Engineering materials
Course Name:
Fracture of Engineering materials (MT419)
Programme:
Semester:
Category:
Credits (L-T-P):
Course Outcomes:
CO1: To identify different types of failures and their causes
CO2: To be able to determine fracture toughness and importance of different theories in the study of fracture mechanics
CO3: To understand microstructural aspects of the material and method of crack propagation
CO4: To develop a material for fracture safe design
Course modules and teaching hours:
Module 1: (08 hours)
Failure and their causes - techniques of failure analysis, conventional design concepts, inadequacies of Conventional design
Module 2: (12 hours)
mechanics of fracture, theoretical cohesive strength, Griffith theory of fracture, Irwin - Orowan modification, concepts of G and R, relation between G and rate of change of compliance, crack tip stress fields, stress intensity factors, relation between G and K, fracture toughness: determination of fracture toughness, ASTM standards; crack tip plasticity, plastic enclaves and their effect on energy release rate, concept of plastic zone criterion, R curve concept, J Integral, COD criterion.
Module 3: (12 hours)
brittle and ductile fractures, fatigue crack growth and fracture mechanics, stress corrosion cracking, liquid metal embrittlement, hydrogen embrittlement, microscopic aspects of cleavage crack propagation, plastic relaxation at crack tip, nucleation of cleavage cracks by plastic deformation, crystallographic mechanism, initial growth and propagation, ductile - brittle transition; designing and testing for fracture resistance.
Module 4: (06 hours)
Principles of fracture safe design, testing procedure, designing steels for fracture resistance, improved toughness in ceramics, composites, case studies in failure analysis.