ML3002 Creep and Fatigue Behaviour of Materials Syllabus:
ML3002 Creep and Fatigue Behaviour of Materials Syllabus – Anna University Regulation 2021
COURSE OBJECTIVES:
The main learning objective of this course is to prepare the students for:
1. Acquiring knowledge on the framework of plastic deformation, its mechanism and the role of dislocations.
2. Recognizing the mechanism, metallurgical variables and methods of life prediction of materials under creep
3. Getting an insight to the nature of stress, factors and life prediction under fatigue.
4. Understanding the micro-mechanics and micro structural aspects involved in fatigue
5. Gaining knowledge to perform failure analysis.
UNIT – I INTRODUCTION
Mechanisms of plastic deformation- Slip and Twinning, Critically resolved stress, Strength of perfect crystal, Lattice resistance to dislocation movement, Elastic properties of dislocation , Dislocation interactions, Partial dislocation, Dislocation multiplication, Dislocation pile up, effect of stacking fault and strain hardening exponent on dislocation.
UNIT – II HIGH – TEMPERATURE DEFORMATION RESPONSE
Creep of Solids, Temperature stress – Strain rate relation, Deformation mechanism, Super plasticity deformation mechanism maps, Creep and stress rupture test, Effect of metallurgical and test variables on creep and fracture. Generation and analysis of creep and creep-rupture data, Parametric methods for prediction of long time properties data, materials for elevated temperature.
UNIT – III CYCLIC STRESS AND STRAIN FATIGUE
Macro fractrography of fatigue failures , Characteristics of fatigue failure, Stress cycles, Fatigue tests, fatigue limit and fatigue strength, S-N curves, types of stress variations, terminology, High cycle and low cycle fatigue , Effect of mean stress on fatigue, Soderberg, Goodman and Gerber equations, stress raisers, stress concentration factor, notch sensitivity factor, factors affecting fatigue limit, finite life, equivalent stress, combined variable stress
UNIT – IV FATIGUE CRACK INITIATION PROPAGATION
Mechanisms of fatigue crack nucleation and propagation, Effect of metallurgical variables on fatigue, effect of overloading pulse, variable stress amplitude, crack closure, Stress and crack lengths correlations with FCP, Fracture modes in Fatigue ,Micro structural aspects of FCP in metal alloys. Thermo-mechanical fatigue, cumulative damage- Miner law, corrosion fatigue, case studies.
UNIT – V ANALYSIS OF ENGINEERING FAILURES
Typical defects, Microscopic surface examination, metallographic and fractographic examination, Fracture surface preservation – Cleaning and replication techniques and image interpretation, failure data retrieval, Component failure analysis : procedural steps for investigation of a failure for failure analysis, Preparation of failure analysis report.
TOTAL: 45 PERIODS
COURSE OUTCOMES:
Upon completion of this course, the students will be able to:
1. Discuss the mechanisms of the role of dislocation and stacking fault on plastic deformation.
2. Assess the behavior of materials under high temperature, metallurgical factors and life prediction of high temperature materials.
3. Distinguish the characteristics, factors and method of life prediction in the stress and strain controlled fatigue.
4. Appraise the micro-mechanics and micro-structural aspects of fatigue.
5. Design and develop a procedure to perform failure analysis and generate a report.
TEXT BOOKS:
1. Richard. W. Hertzberg ,“ Deformation and Fracture Mechanism of Engineering Materials”, John Willey and Sons, 5th edition, 2012.
2. Thomas H Courtney,“ Mechanical Behaviour of Materials”, Waveland press, 2005.
REFERENCES:
1. Josef Cadek, .,“ Creep in Metallic Materials”, Elsevier,1988
2. Norman E Dowling, “Mechanical Behavior of Materials: Engineering Methods for Deformation, Fracture and Fatigue” Pearson. 2013.
3. Prashant Kumar,” Elements of Fracture Mechanics”, Tata McGraw-Hill,2009.
4. Suresh S, “ Fatigue of materials”, Cambridge University press, 1998.
5. William T Becker, Failure analysis and Prevention, ASM international, 2002.