APL765 Fracture Mechanics

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Course info

Credit: 3 Units (3-0-0).

Instructor: Dr. Md Rushdie Ibne Islam, Email: rushdie@am.iitd.ac.in, Office: 4B-19 (Block IV, top floor).

Class timings:

• Lecture: Wednesday (3 PM - 4.30 PM), and Friday (5.30 PM - 7 PM); LH 603

TAs: Ranu Raj, Vikram Parmar and Subhanu Banerjee.

Office hours: Either stop by instructor's office (for quick discussion) or take an email appointment (for longer discussion).

Important note: Please include APL765 (without space) in the subject line for all email communications related to this course.

Syllabus

• Part I: Fundamentals of Fracture Mechanics
  • Fracture: an overview; types of fracture; significance in engineering design.
  • Theoretical cohesive strength and defect population in solids.
  • Stress concentration factor; notch effects and strengthening.
  • Elements of fracture mechanics; crack initiation and propagation.
  • Griffith’s crack theory; energy-based approach to fracture.
  • Stress analysis of a crack; stress intensity factor and fracture modes (I, II, III).
• Part II: Linear and Nonlinear Fracture Mechanics
  • Energy and stress field approaches; crack tip fields.
  • Plane stress and plane strain conditions; their influence on fracture behavior.
  • Fracture toughness testing: K_IC, test methods and standards.
  • Crack opening displacement (COD) and its measurement.
  • Elastic-plastic fracture mechanics; J-integral and R-curve concepts.
  • Ductile-brittle transition; Charpy impact testing.
  • Correlation between impact energy and fracture toughness.
  • Microstructural aspects affecting fracture resistance.
• Part III: Fatigue, Environmental Effects, and Failure Analysis
  • Environmental assisted cracking: stress corrosion cracking, hydrogen embrittlement.
  • Cyclic stress and strain-based fatigue analysis.
  • Fatigue crack propagation: Paris law, threshold behavior, and influencing factors.
  • Crack closure and load ratio effects.
  • Engineering case studies: fatigue and fracture failures.
  • Failure analysis methodology and prevention strategies.

References

• Primary
  • Anderson, T.L. Fracture Mechanics Fundamentals and Applications.
  • Kumar, P. Elements of Fracture Mechanics.
• Additional
  • Maiti, S.K. Fracture Mechanics Fundamentals and Applications.

Grading

• Quiz #1: 10%
• Minor: 25%
• Quiz #2: 10%
• Major: 35%
• Assignments: 10%
• Term paper: 10%

If a student decides to audit the course, the passing grade will be 40%. Additionally, the student must write minor and major exams, and the attendance must be greater than or equal to 75% in lectures and tutorials separately.

Quizzes, minor and major

• Two quizzes will be conducted; one (quiz #1) before and another (quiz #2) after the minor exam. Exact date, time and place will be notified later.
• Minor and major exams will be scheduled based on the institute timetable.

Homework

• Homework will be assigned almost every week. These will not be graded. Hence, submission is not necessary.
• Students are strongly encouraged to try the homework problems.

Attendance

• Students are strongly encouraged to attend all the lectures sessions. Attendance will be recorded for each lecture session. If a student's attendance is less than 75%, the student will be awarded one grade less than the actual grade that he/she has earned. For example, a student who has got an A grade but has attendance less than 75% will be awarded an A (-) grade. However, please note that there are no marks for attendance.
• In case of absence due to unforeseen circumstances, such as medical reasons, the student must inform the instructor via email within a week from the date of absence.
• If a student cannot appear for an exam due to medical reasons, a medical certificate needs to be produced from IIT Delhi hospital for consideration of time extension or re-exam.