ED4092 Engineering Fracture Mechanics Syllabus:
ED4092 Engineering Fracture Mechanics Syllabus – Anna University PG Syllabus Regulation 2021
COURSE OBJECTIVES:
1. Formulation of governing equations for elastic problems
2. Stresses calculations/displacements around the crack tip for different modes of fracture
3. Estimation of K1c/SIF/critical flaws/failure stresses for different crack geometries
4. Life assessment of the cracked components under different types of repeated/variable
fatigue loads and design for its life extension.
5. Analysis of failed engineering components under different modes of fracture.
UNIT-I ELEMENTS OF SOLID MECHANICS
Introduction to Failure and Fracture- Spectacular Failures-Basics Principles-Governing equations for the deformable body-Stress-Strain relations and general equations of elasticity in Cartesian and Polar Coordinates-vectors and tensors-differential equations of equilibrium-compatibility boundary conditions-representation of three-dimensional stress system -generalized hook’s law – plane stress and stain problems – Airy’s stress function. Methods of formulation of Governing Differential equations for plane elasticity-Naviers Equation-Biharmonic equation in Cartesian and polar coordinates.
UNIT-II STRESS AND DISPLACEMENT AROUND THE CRACK TIP FOR DIFFERENT MODES OF FRACTURE
Brittle and Ductile Fracture-Modes of Fracture-Weakness of the components due to Flaws-Need for Linear Elastic Fracture Mechanics (LEFM) – Evaluation of Structural Design-Stress and displacement around the crack tip in K-annulus for Mode-I and Mode-II plane crack problems – Stress and displacement around the crack tip in K-annulus for Mode III crack problems
UNIT-III STATIONARY CRACK UNDER STATIC LOADING
Griffith analysis- Irwin’s approximation-CTOD and stress ahead of the crack tip- Westergaard solutions: Analytical Calculations for SIF for different crack geometries-Critical crack length and fracture stress calculations.
Two dimensional elastic fields – Analytical solutions for small scale yielding near a crack front –plastic zone size –Specimen size calculations: K1c Testing for Fracture toughness of the Material.
UNIT-IV FATIGUE FAILURE AND ENVIRONMENTAL-ASSISTED FRACTURE
Introduction to fatigue failure-S-N Curve-Crack Initiation-Crack propagation- Effect of an Overload-Variable amplitude Fatigue load-Crack closure- Characteristics of fatigue crack-Paris Law- Fatigue Crack Growth Test to evaluate Paris constants- life calculations for a given load amplitude –effects of changing the load spectrum
Environmental-assisted Fracture-Micro mechanisms-factors influencing Environmental-assisted fracture-Environment-assisted Fatigue Failure affecting fatigue performance, fatigue loading, constant and variable amplitude loading.
UNIT-V APPLICATIONS OF FRACTURE MECHANICS
J-integral, Mixed-mode fracture, Crack arrest methodologies- Case studies: Analysis on failed components and design for the extension of its life
COURSE OUTCOMES:
On Completion of the course the student will be able to
CO1 Formulate governing equation for elastic problems
CO2 Calculate stresses/displacements around the crack tip for different modes of fracture
CO3 Estimate K1c/SIF/critical flaws/failure stresses for different crack geometries
CO4 Assess the life of the cracked components under different types of repeated/variable fatigue loads and design for its life extension.
CO5 Analyze failed engineering components under different modes of fracture.
REFERENCES:
1. Broek, David, ”Elementary Engineering Fracture Mechanics “, Springer Netherlands, 1982.
2. John M.Barson and Stanely T.Rolfe, “Fatigue and fracture control in structures”, Butterworth-Heinemann; 3rd edition. 1999
3. Kare Hellan, “Introduction of Fracture Mechanics”, McGraw-Hill Book Company, 1985
4. Prashant Kumar, “Elements of Fracture Mechanics”, Tata McGraw-Hill Publishing Company Ltd, 2009.
5. Ted L. Anderson, “Fracture Mechanics: Fundamentals and Applications”, CRC Taylor and Francis, 4th Edition, 2017
6. Tribikram Kundu, “Fundamentals of Fracture Mechanics”, Ane Books Pvt. Ltd. New Delhi/ CRC Press, 1st Indian Reprint, 2012