Faculdade de Ciências e Tecnologia

Mechanics of Materials II

Code

10195

Academic unit

Faculdade de Ciências e Tecnologia

Department

Departamento de Ciências dos Materiais

Credits

6.0

Teacher in charge

João Paulo Miranda Ribeiro Borges, Maria Teresa Varanda Cidade

Weekly hours

5

Total hours

98

Teaching language

Português

Objectives

Mechanics of Materials II objective is the study of the mechanical behavior of some important classes of materials not considered in the first unit, Mechanics of Materials I – these are essentially the fluids and the polymeric materials. The study of fluids is initiated in the unit of Physics I, at a very elementary level, and here we aim at giving the student a wider view about their mechanical behavior. As to the polymers, the knowledge already acquired in previous units is applied and developed, in the study of two phenomena of the utmost practical importance, as is the case with elasticity and viscoelasticity. The objective is the understanding by the student of these phenomena, and the molecular characteristics lying on its genesis, so that in their professional life, in a manufacturing environment, he or she will be able to judge and determine the physical-chemicalstructure that will better generate the properties envisaged for the material.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Prerequisites

It is required a convenient preparation in the areas of Physics - mainly Newtonian Mechanics, and Mathematics - mainly Euclidean geometry, Vector calculus and Differencial and integral calculus. A basic knowledge of Polymer physics is also required, although a general review on this topic is included in the program of the unit. The knowledge required in this areas is provided by some previous units of the Course, namely Análise Matemática I, II and III, Física I and Física de Polímeros.

Subject matter

Chapter 1. Basic concepts of Tensor analysis.

Chapter 2. Tensions.

Chapter 3. Deformation and Deformation rate. Vorticity.

Chapter 4. General principles: conservation of mass, linear momentum, angular momentum and energy, second law of Thermodynamics.

Chapter 5. Constitutive equations of Elasticity.

Chapter 6. Mechanical behaviour of polymers.

Chapter 7. Viscoelasticity: viscoelastic models, master curves, time-temperature superposition principle, WLF equation. 

 

 

Bibliography

I.M.Ward, J.Sweeney, “An introduction to the Mechanical Properties of Solid Materials”, John Wiley and Sons Ltd, 2004.

N.Phan-Thien, “Understanding Viscoelasticity”, Springer-Verlag, Berlin, 2002

J.B.Ferreira, "Mecânica dos Materiais II", FCT/UNL, 2011.

R. C. Arridge, "Mechanics of Polymers", Clarendon Press, Oxford, 1975

Teaching method

There are theoretical classes, practical problem-solving classes and laboratory sessions. In the theoretical classes, the program of the unit is presented, focusing the understanding of the topics treated. In the practical classes, problems are solved, envisaging the practice with mathematical techniques, and also the understanding of physical laws and phenomena related to the flow of fluids, non linear elasticity exhibited by elastomers and viscoelasticity of polymers. In the Lab., simple experiences are carried, with elastomers, viscoelastic materials, films and membranes. The evaluation has two parts, a practical one based on the work done by the student in the Lab., and a theoretical one based on the program presented in the other two types of classes. The latter is materialized in a final exam or, as an alternative, four tests. The final mark is the weighted average of these two parts, their weights being 20% and 80%, respectively.

 

Evaluation method

The unit has a practical component, leading to a mark NP, and a theoretical-practical component, leading to a mark NT. Both range from 0 to 20 points. For approval in the unit, with a final mark N, a student needs a mark of at least 10 points in each component. N will be given by  N = 0,3 NP + 0,7 NT.

NP is an average mark obtained in two laboratory sessions, and NT can be obtained in two different ways: either by averaging the marks obtained in three written tests, or alternatively, it is the mark obtained in a final exam. Each student is allowed to follow both methods, and NT will be the best of the two marks thus obtained.

The students must carry out all the lab sessions, otherwise they will be excluded.

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