Rheology of materials

Rheology is the study of material deformation and flow under applied mechanical stress. In the field of materials, this science particularly concerns the following areas:

            - Viscoelasticity

            - Plasticity

            - Viscoplasticity

            - Non-Newtonian fluids

In practice, rheology is used to characterize the macroscopic mechanical properties of materials whose behavior escapes the classical theories of elastic solids and Newtonian fluids (with constant viscosity). Such materials can thus be considered as having an intermediate behavior between solid and fluid, between elastic and viscous.

The aim of this teaching unit (UE) is to enable L3 mechanics students to gain a better grasp of certain other L3 courses (in particular, strength of materials, fluid mechanics, mechanics of deformable solids and structural design), and to prepare them for future Master's courses (generalized standard materials, etc.).

To this end, this course will describe the typical mechanical behaviors of different classes of materials (metals, polymers, granular materials, wood, etc.), relating them to their specific (micro-)structural organizations and composition, which guide their modes of deformation. The notions of isotropy, orthotropy, transverse isotropy and total anisotropy will be covered. In addition, the main types of experimental tests (e.g. uni-axial tension, bi-axial tension...; strain-hardening, creep, relaxation tests...; etc.) will be presented.

Rigid solid mechanics

Recommended prerequisites* :

Knowledge of materials and their classification

Final examination

1) Different types of materials

2) Different types of experimental trials

3) Different mechanical behaviors (associated with these experimental tests)

4) Rheological models to represent these behaviors

1. a) Rheological models: The course begins with a general presentation of the distinctions between solid and fluid behavior, elastic and viscous behavior, and the corresponding temporal aspects. An introduction to plasticity (fluid-like deformation of a solid beyond a threshold mechanical stress) is also presented.

Next, the main rheological models (and their associated analog models) are shown, together with their use in determining the corresponding mechanical properties. Finally, methods for combining these models (in series and/or in parallel) in order to develop more complex ones are developed.