De G514 Handout

BIRLA INSTITUTE OF TECHNOLOGY & SCIENCE INSTRUCTION DIVISION FIRST SEMESTER 2011-2012 Course Handout (Part II) Date: 06/01/2012 In addition to part I (General Handout for all courses appended to the time table) this portion gives further specific details regarding the courses. Course No Course Title Instructor-in-charge

: : :

DE G514 FRACTURE MECHANICS VIKAS CHAUDHARI

Course Description: Types of failure, Types of fracture, Modes of fracture, Fracture criteria, Energy release rate, Stress intensity factor (SIF), SIF of more complex cases, Anelastic deformation at the crack tip, Elastic plastic analysis through J-integral, Crack tip opening displacement, Test methods, Fatigue failure, Numerical analysis, Mixed mode crack initiation and growth.

Scope and objective of the course: The conventional design is based on yield point. However, it has been found that often a structural component fails even when the worst loaded point is well within the yield stress. Thus the design based entirely on avoiding yielding is not adequate for certain cases. Fracture mechanics is based on implicit assumption that there exists a crack in the structural component.

Text Book Ref. Book Lect. No. 1

2 to 6

7 to 11

12 to 16

: Prashant Kumar, Elements of Fracture Mechanics, TMH. : T. L. Anderson, Fracture Mechanics; Fundamentals and Applications. Learning Objectives

Background

Energy release rat rate

Stress intensity factor 

SIF of more complex cases

Topics to be covered Kinds of failure and history Dilemma of Griffith, Surface energy, Griffith’s realization Griffith’s analysis, Mathematical formulation, Thin  plate vs thick plate plate Critical energy release rate. Linear elastic fracture mechanics (LEFM) Stress and displacement fields in isotropic elastic materials, Elementary properties of  complex variables Approach of westergaard Other application of westergaard approach, Application of the  principle of superposition, superposition, Crack  in a plate of finite f inite dimensions Edge cracks, Embedded cracks, Relation between G I and K I

Ref. Chap./Sec. 1.1-1.7

2.1 to 2.13

3.1 – 3.6

4.1 - 4.9

17 – 21

Anelastic deformation at the crack Tip

18 to 22

Elastic plastic analysis through J-Integral

20 to 22

Crack tip opening displacement

23 to 28

Test methods

29 to 32

33 to 36 37 - 42

Fatigue failure

 Numerical Analysis Mixed mode crack  initiation and growth

Further Investigation at the crack tip, Approximate shape and size of the plastic zone, Effective crack length, Effect of   plate thickness. Relevance and scope, Definition of J-Integral, Path independence Stress-strain relation, Further  discussion on J-Integral, Engineering approach-A short cut. Relationship between CTOD, K I and GI for small scale yielding Equivalence between CTOD and J. K IC test techniques, Test methods to determine J IC, Test methods to determine G IC and GIIC, Determination of critical CTOD. Terminology, S-N curve, Crack  initiation, Crack propagation Effect of an overload, Crack  closure, Variable amplitude fatigue load.

5.1 – 5.5

6.1 – 6.7

7.1 – 7.4

8.1 – 8.6

9.1 – 9.4

Finite element method

10.1 – 10.3

Fracture surface, Mixed mode crack propagation criteria, Crack  growth.

11.1 – 11.5

Evaluation Scheme: EC No. 1 2 3 4 5

Evaluation component Test 1 Test 2 Compre. FEM based project Seminar

Duration

Weightage

1 Hr. 1 Hr. 3 Hrs.

20% 20% 40% 15% 5%

Date, Time Nature & Venue component 21.02.2012 CB/OP 29.03.2012 CB/OP 10.05.2012 OB + CB will be announced later 

Chamber Consultation Hours: To be announced in the class. Notices: Course ftp.

Instructor-in-charge (DE G514)

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