Fatigue and Fracture Mechanics

Code:

EM0067

Acronym:

FMF

Keywords
Classification	Keyword
OFICIAL	Applied Mechanics

Instance: 2011/2012 - 1S

Active?	Yes
Responsible unit:	Applied Mechanics Section
Course/CS Responsible:	Master in Mechanical Engineering

Cycles of Study/Courses

Acronym	No. of Students	Study Plan	Curricular Years	Credits UCN	Credits ECTS	Contact hours	Total Time
MIEM	21	Syllabus since 2006/2007	5	-	6	56	160

Teaching language

Portuguese

Objectives

This course aims to acquaint students with knowledge related to the structural integrity assessment of mechanical constructions in case of crack.
What is taught on this course is relevant to equipment development taking into account equipment failures (fatigue) and interpretation of the causes of structural failure (“failure analysis”).

By the end of the semester, students should be capable of:
- selecting procedures to assess the structural integrity of mechanical components, structures, structural connections with cracks;
- coordinating the analysis of the causes by fracture and fatigue in real cases;
- interpreting papers related with norms and codes associated with fracture and fatigue.

Program

1. Linear elastic fracture mechanics; stress analysis of cracks; concept of stress intensity; method energy K; concept of energy liberation rate; Relations between K and G; plastic region in cracks; plane state of stress and deformation; equivalent elastic crack; tenacity in plane state of stress- KIC; ASTM E339 norm; resistance curve and stability propagation of cracks; experimental tenacity;
2. Elasto-plastic fracture mechanics; Dugdale’s method; crack opening displacement- tests and normalization; welding institute design curve; Relationship between J-integral and Cod;
3. stable crack propagation: fatigue and corrosion under stress; Paris’ law; concept of threshold propagation; relationship between SN tests (Wohler) and fracture mechanics tests;
4. Application of fracture mechanics to composite material;
5. Failure analysis; CEBG R6 procedure;
6. Computing fracture mechanics; calculation of J integral, energy liberation rate and the stress intensity factor.

Mandatory literature

Knott, John; Fracture mechanics. ISBN: 0-901716-28-6
Ewalds, H. L.; Fracture mechanics
Sanford, R. J. 340; Selected Papers on Crack Tip Stress Fields. ISBN: 0-912053-56-9
Anderson, T. L.; Fracture mechanics. ISBN: 0-8493-4277-5
Broek, David; Elementary engineering fracture mechanics. ISBN: 90-247-2656-5
Branco, Carlos Augusto Gomes de Moura; Fadiga de estruturas soldadas

Complementary Bibliography

Sanford, R. J. 340; Selected Papers on Foundations of Linear Elastic Fracture Mechanics. ISBN: 0-912053-55-0
Bazant, Zdenek P.; Fracture and size effect in concrete and other quasibrittle materials. ISBN: 0-8493-8284-X
Gdoutos, E. E.; Fracture mechanics criteria and applications. ISBN: 0-7923-0605-8

Teaching methods and learning activities

This course is divided into practical and theoretical classes. There is a session in the laboratory, where students can get in touch with equipments and test procedures. In addition, assignments will be discussed.

Software

Ansys 5.7

Evaluation Type

Evaluation with final exam

Calculation formula of final grade

Final Mark will be based on the final exam mark. However, the quality of the assignments and students’ assiduity will be taken into account.

Examinations or Special Assignments

Students will be encouraged to do assignments.

Observations

This course can be taught in English due to the number of foreign students. However, Portuguese students may not agree, which has happened in previous years.