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
Maria Teresa Varanda Cidade
Weekly hours
5
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
W. Lai, David Rubin, Erhard Krempl, "Introduction to Continuum Mechanics", Butterworth Weinemann for Elseivier, USA, 1999.
I.M.Ward, J.Sweeney, “An introduction to the Mechanical Properties of Solid Materials”, John Wiley and Sons Ltd, 2004.~
R. C. Arridge, "Mechanics of Polymers", Clarendon Press, Oxford, 1975
N.Phan-Thien, “Understanding Viscoelasticity”, Springer-Verlag, Berlin, 2002
Teaching method
Theoretical classes, problems'' resolution classes and practical laboratory classes. In the theoretical classes, the subject of the program is presented, focusing on the understanding of the different topics covered. The problems'' resolution classes are designed to practice mathematical techniques used in Materials Mechanics, and help to understand the physical phenomena involved in the flow of fluids, especially non-Newtonian fluids, in the elasticity of elastomeric materials and in the viscoelasticity of polymers. In the Laboratory, tensile and impact tests are planned on different types of commercial thermoplastic polymers. In the evaluation, a positive participation in the Laboratories is required, which is necessary to obtain frequency in the course, as well as a positive result in the continuous evaluation or, alternatively, in the final exam. For the purposes of continuous evaluation, two tests and one mini-test (evaluation of laboratory classes) are carried out during the semester. The mini-test score contributes 20% to the final score, and the average of the two tests or the exam contribute the remaining 80%.
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 9.5 points in each component. N will be given by
N = 0,2 NP + 0,8 NT.
NP is an average mark obtained in an individual quiz relative to two laboratory sessions, and NT can be obtained in two different ways: either by averaging the marks obtained in two written tests, or alternatively, it is the mark obtained in a final exam.
To perform the UC by continuous evaluation it is necessary that the grade of the 1st test is not lower than 7.5 values. Otherwise, the student is admitted to the exam, provided he obtained NP higher than 9.5 val..
The students must carry out all the lab sessions, otherwise they will be excluded.