Rheology of materials

Rheology is the study of the deformation and flow of matter under the effect of applied mechanical stress. In the field of materials, this science is particularly relevant to the following areas:

            - Viscoelasticity

            - Plasticity

            - Viscoplasticity

            - Non-Newtonian fluids

In practice, rheology is used to characterize the macroscopic mechanical properties of materials whose behavior defies classical theories of elastic solids and Newtonian fluids (with constant viscosity). Such materials can therefore be considered as having behavior that lies between that of solids and fluids, between elastic and viscous.

The objective of this Teaching Unit (TU) is to enable third-year mechanical engineering students to better understand certain other third-year courses (in particular, material resistance, fluid mechanics, deformable solid mechanics, and structural design) and to prepare them to better tackle future courses in the Master's program (generalized standard materials, etc.).

To this end, this EU will outline the different typical mechanical behaviors of different classes of materials (metals, polymers, granular materials, wood, etc.) by linking them to their specific (micro)structural organizations and compositions, which guide their modes of deformation. The concepts of isotropy, orthotropy, transverse isotropy, and total anisotropy will be addressed. In addition, the main types of experimental tests (e.g., uniaxial tensile, biaxial tensile, work hardening, creep, relaxation, etc.) will be presented.

Rigid body mechanics

Recommended prerequisites:

Knowledge of materials and their classification

Final exam

1) Different types of materials

2) Different types of experimental tests

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 overview of the distinctions between solid and fluid behavior, elastic and viscous behavior, considering the corresponding temporal aspects. An introduction to plasticity (fluid-like deformation of a solid beyond a mechanical stress threshold) is also presented.

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