AE1011 FATIGUE AND FRACTURE 3 0 0 100
OBJECTIVE
To study the concepts of estimation of the endurance and failure mechanism of components
1. FATIGUE OF STRUCTURES 7
S.N. curves - Endurance limits - Effect of mean stress, Goodman, Gerber and Soderberg relations and diagrams - Notches and stress concentrations - Neuber’s stress concentration
factors - Plastic stress concentration factors - Notched S.N. curves.
2. STATISTICAL ASPECTS OF FATIGUE BEHAVIOUR 10
Low cycle and high cycle fatigue - Coffin - Manson’s relation - Transition life - cyclic strain hardening and softening - Analysis of load histories - Cycle counting techniques -Cumulative damage - Miner’s theory - Other theories.
3. PHYSICAL ASPECTS OF FATIGUE 10
Phase in fatigue life - Crack initiation - Crack growth - Final Fracture - Dislocations - fatigue fracture surfaces.
4. FRACTURE MECHANICS 10
Strength of cracked bodies - Potential energy and surface energy - Griffith’s theory - Irwin - Orwin extension of Griffith’s theory to ductile materials - stress analysis of cracked bodies - Effect of thickness on fracture toughness - stress intensity factors for typical geometries.
5. FATIGUE DESIGN ANDTESTINIG 8
Safe life and Fail-safe design philosophies - Importance of Fracture Mechanics in aerospace structures - Application to composite materials and structures.
TOTAL : 45
TEXT BOOKS
Prasanth Kumar – “Elements of fracture mechanics” – Wheeter publication, 1999.
Barrois W, Ripely, E.L., “Fatigue of aircraft structure”, Pe/gamon press. Oxford, 1983.
REFERENCES
1. Sin, C.G., “Mechanics of fracture” Vol. I, Sijthoff and w Noordhoff International Publishing Co., Netherlands, 1989.
2. Knott, J.F., “Fundamentals of Fracture Mechanics”, Buterworth & Co., Ltd., London, 1983.
EmoticonEmoticon