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Mechanical Behaviour of Materials

Objectives

The subject aims at providing students with knowledge on:

 - mechanical properties of major groups of materials in engineering;

- phenomenological aspects of plasticity;

- mechanical tests;

- concepts and applications of fracture mechanics, fatigue and creep;

- criteria for creep and fatigue design;

- concepts of stress corrosion.

General characterization

Code

3660

Credits

6.0

Responsible teacher

Catarina Isabel Silva Vidal, Telmo Jorge Gomes dos Santos

Hours

Weekly - 4

Total - 56

Teaching language

Português

Prerequisites

Students are requested to have completed Materials Science and Solid Mechanics I.

Bibliography

- Jorge Rodrigues e Paulo Martins, Tecnologia Mecânica - vol.1, ed. Escolar Editora, 2005.

- Martins Ferreira, Comportamento mecânico de materiais, ed. FCTUC, 1999.

- Ashby, Michael F., Jones, David R.H., “Engineering Materials 1: An introduction to their properties and applications”, 2nd Edition, Butterworth Heinemann, 1996.

Teaching method

In lectures the material is presented and discussion is promoted. There is some lab work to promote the contact of the student with a variety of experimental equipment.

Evaluation method

Option 1: Continuous Evaluation

- 1st Test (T1) in person;

- 2nd Test (T2) in person;

- Case study with report, presentation and discussion.

 Final grade = 0.70 x [(T1 + T2)/2] + 0.30 x Case study

with  [(T1 + T2)/2] >= 9.0 values and Case Study >= 9.5 values

To obtain frequency, the student must have at least 9.5 values in the Case study. Students with frequency in previous academic years are automatically admitted to evaluation this year.

The student will be approved if the Final grade is equal to or greater than 9.5 values, while complying with the requirements established.

If the student has a Final grade equal to or higher than 18 values, an oral exam will be held to defend the grade.

 

Option 2: Final Exam  

All students with frequency to the discipline have access to the final exam.

The exam has a minimum grade of 9.0 values.

The exam will be in person.

The final grade will be:

Final grade = 0.70 x Exam + 0.30 x Case Study

with Exam > = 9.0 values  and  Case Study >= 9.5 values.

The student will be approved if the grade of the final grade is equal to or higher than 9.5 values, while complying with the requirements established.

If the student has a final grade equal to or higher than 18 values, an oral exam will be held to defend the grade.


If the student fails, the grade of the case study will remain valid for, at least, 1 academic year.

Subject matter

Theory and concepts of plasticity. Mechanical testing.
 
Fracture mechanics: microstrutural characteristics of fracture. Stress intensity factor. J Integral. Stress distribution at crack tip. Experimental methods of evaluation of fracture toughness. Nucleation and crack propagation in ductil materials.
 
Fatigue: microstrutural characteristics. Fatigue limit. Types of fatigue and characteristics. Applicable laws in each domain. Design of components under fatigue conditions. Neuber rule. Iniciation and propagation of styress corrosion cracks under corrosion environment. Fatigue in welded structures.

Creep and stress relief.

Stress corrosion. Fundamentals.

Case studies in service conditions.