Positionnement dans le cursus
Semestre 5
Intersemestre
Semestre 6
 
 
 
Semestre 7
 
Intersemestre
Semestre 9
 
 
Intersemestre

Course unit

Equivalent behaviors

Last updated: 22/02/2024

Edit

Course Director(s):

MORIN Claire

General Description:

Continuum mechanics provides tools for modelling the behaviour of dense media on a scale considered as macroscopic, since the notion of the microstructure of materials is absent and simply represented by more or less sophisticated equivalent properties (c/f Mechanics of Materials Unit). Conversely, at their microstructure scale, materials are heterogeneous and behaviour observed at the macroscopic scale is the result of elementary physical mechanisms, active at the microstructure scale.

During the course the student will gradually come to understand the notions of scale and separation of scale and its influence on observed behaviour.

The student will be capable of defining an Elementary Representative Volume and of making the link with the notion introduced in continuum mechanics.

The student will know the principle methods of scale changing, allowing a deduction of the effective behaviour of a heterogeneous material based on knowledge of its microstructure, but will also be able to estimate local constraints inside a microstructure. 

Finally an application of the various notions of high performance composite materials, commonly used in many industries (in particular the aeronautical industry), will be proposed at the end of the course.

Teaching methods include courses and supervised studies and two practical numerical courses. An experimental practical course is also planned.

Key words:

Micromechanical approach Heterogeneity Homogenisation Laminated composites Matrices and Inclusions Monocrystalline and Polycrystalline Elasticity Anisotropy

Number of teaching hours

40

Fields of study

Materials Science Mechanical Engineering

Teaching language

French

Intended learning outcomes

On completion of the unit, the student will be capable of: Classification level Priority
Describing the microstructure of a material in micromechanical terms 1. Knowledge Important
Determining the pertinent scales for studying a material 3. Apply Essential
Calculating the effective behaviour of a heterogeneous material 3. Apply Important
Understanding the different methods of scale change 2. Understand Important
Designing a composite structure according to the requirements in effective behaviour 7. Create Important
Estimating the effective behaviour of a composite material 6. Assess Important

Learning assessment methods

Percentage ratio of individual assessment Percentage ratio of group assessment
Written exam: 75 % Project submission: 0 %
Individual oral exam: 0 % Group presentation: 0 %
Individual presentation: 0 % Group practical exercise: 0 %
Individual practical exercise: 25 % Group report: 0 %
Individual report: 0 %
Other(s): 0 %

Programme and content

Type of teaching activity Content, sequencing and organisation
(inter)active Amphitheatre
  1. Homogenisation in mechanics (28h)
    1. Tensor calculus and elastic anisotropy
    2. Notions of scale and the micromechanical approach to behaviour
    3. Theory of effective modules (Boundaries of Voigt and Reuss)
    4. Homogenisation of random media
      • Eshelby’s problems
      • Reinforced particle composites – model without interaction
      • Reinforced particle composites: Mori-Tanaka estimation
      • Hashin and Shtrikman boundaries
      • Micromechanical models for polycrystalline materials
    5. Periodical homogenisation
  2. Composites (12h)
    1. Generalities of high performance composites
    2. Behaviour of unidirectional folds in and outside of their orthotropic axes
    3. Fold scale resistance
    4. Composite section beams
    5. Laminated plates
Supervised studies

When possible each course will be followed by a session of exercises to apply the notions dealt with in class. Approx. n° of hours : 12h

Practical courses

3h (or 6h) in common with the structural materials unit. Characterisation of the mechanical behaviour of composite structures.

Practical courses

2 numerical practical work sessions are proposed : 1/ simple numerical calculation of effective behaviour (Mori-Tanaka type) and 2/ auto-coherent type