Deformation and fracture of materials

Teacher(s)

Idrissi Hosni; Pardoen Thomas;

Language

English

Main themes

The main topics involve

1. The physical and mathematical description at the atomic, microscopic and macroscopic scales of the (thermo-visco-) elastic deformation mechanisms within all material classes;
2. The physical and mathematical description at the atomic, microscopic and macroscopic scales of the (visco-) plastic deformation mechanisms within all material classes, involving creep;
3. The physical and mathematical description at the atomic, microscopic and macroscopic scales of the damage and fracture mechanisms within all material classes, involving fracture mechanics theory.

Aims

At the end of this learning unit, the student is able to :
1	Contribution of the course to the program objectives Having regard to the LO of the programme KIMA, this activity contributes to the development and acquisition of the following LO: LO1 Foundations of scientific and technical knowledge (LO1.1, LO1.2, LO1.3) LO2 Engineering skills (LO2.1, LO2.2, LO2.5) LO3 R & D skills (LO3.2) LO5 Efficient communication (LO5.3) LO6 Ethics and professionalism (LO6.1, LO6.3) Specific learning outcomes of the course At the end of this course, the student will be able to LO1.1. Distinguish and classify the different classes of mechanical behaviour: reversible deformation, permanent deformation (rate dependent or not), damage and fracture; LO1.1. Define the macroscopic properties characterizing the mechanical performances of materials : stiffness, strength, ductility, creep resistance, fracture toughness and explain how these quantities are measured experimentally and indexed (units); LO1.1 and 1.2. Identify and schematically represent the various mechanisms in terms of length and time scales, interactions and couplings, for the various classes of materials, responsible for the macroscopic properties; LO1.2 and 1.3. Solve simple mechanical problems using the physical/mechanical models derived during the lectures as well as the new concepts discovered in this course (e.g. internal stress, stress intensity factor, energy release rate, '); LO2.1, 2.2, 2.5, 3.2, 6.1, 6.3. Establish, justify and present a strategy of resolution of a complex engineering problem involving plasticity and fracture, implying in particular the simplification of the geometry, of the loading conditions and of the material response in order to reveal to key parameters playing a role; LO5. Speak and understandthe English language better.

Content

Basic concepts
I. Reversible deformation : Chap II Elasticity and thermoelasticity ; Chap III Viscoelasticity, anelasticity
II. Irreversible deformation : Chap IV Macroscopic plasticity ; Chap V Dislocation theory ; Chap VI Hardening mechanisms, link microstructure - plasticity ; Chap VII Viscoplasticity and creep of polymers and metals
III. Damage and fracture : Chap VIII Damage ; Chap IX Fracture mechanics ; Chap X Mechanisms of cracking ; Chap XI Sub-critical crack growth and fatigue (not covered every year) 

Teaching methods

Due to the COVID-19 crisis, the information in this section is particularly likely to change.

Students attend laboratory sessions (typically 5 or 6) by groups of about 10-15 (the group can be divided in two sub-groups for sanitary reasons) during which they perform experiments with the help of researchers. The lab sessions take place before the theoretical courses to follow the deductive scientific methodology.
The theoretical courses are supplemented by application exercises to help the student mastering the new concepts. A fairly comprehensive textbook is provided to the students. The slides used for some of the lectures are available on Moodle (and on TEAMS). The ex-cathedra lectures will be taught in a co-modal format, with all organisation details specified in the roadbook available on TEAMS and Moodle.
Students are also expected to invent and solve a specific engineering problem involving a fracture assessment and relevant sub-problems allowing the introduction of several features covered in the different parts of the course.
All the information on the methods and organisation are provided in the roadbook of the course (see TEAMS and Moodle)

Evaluation methods

Due to the COVID-19 crisis, the information in this section is particularly likely to change.

The students will be individually graded based on the objectives indicated above. More precisely, the evaluation involves the grading of

• short lab reports (about 10%);
• an original exercise invented by the student based on a real engineering problem (see further); the criteria are : (1) creativity/originality in the selection of the problem; (2) diversity of concepts involved in the problem; (3) complexity of the problem; (4) quality/exactness of the approximations/assumptions and solution. The exercise will be presented on paper; an oral discussion is optional. This exercise can be prepared by group of two but each student must provide a specific report involving different values for the parameters appearing in the problem (about 30%);
• the solution to an imposed exercise; the textbook being available for that part of the exam (about 30%);
• the answers, during an oral interrogation, to a few questions of synthesis regarding the main concepts, models and phenomena presented in the course; the list of possible questions is given to the students during the year (about 30%).

The grading of the different notes indicated above (about 10% 30% 30% 30%) will be applied except if there is a deep failure in one of them. More precisely, if one score is equal or below 6/20 for one note, the weight of this note will be increased by one half while the other weights are proportionally decreased. If this level of failure is attained for several notes, this modification is made only on one note, the weakest one except if it is the one for the lab reports. The injustifed absence to several laboratory sessions automatically leads to failure.
The written and opral examination will be carried out on TEAMS or in presential mode depending on the state of the covid crisis.

Other information

The students must be familiar with the basic concepts

• of materials science, and especially of the basics of crystallography and microstructures;
• of continuum mechanics (stress and strain tensors) and of mechanics of deformable solids (linear elasticity theory) that have been taught in the program of bachelor of engineering. Nevertheless, the course primarily aims at illustrating these concepts in practical engineering situations rather than at making extensive use of the mathematics behind.

Online resources

https://moodleucl.uclouvain.be/course/view.php?id=10274

Bibliography

Des livres de référence sont disponibles à la bibliothèque BSE.

Teaching materials

• textbook "deformation and fracture of materials"
• textbook "deformation and fracture of materials"
• textbook "deformation and fracture of materials"
• textbook "deformation and fracture of materials"
• textbook "deformation and fracture of materials"

Faculty or entity

FYKI