5. Behavior

5.1 Elasticity and viscoelasticity

While the linear scheme is a simple way of studying the main properties of composites, it must be used with care. Indeed, composites often challenge conventional approximations. The nature of the mechanical behavior law may vary with direction: elastic and linear in the direction of the reinforcement, it may be non-linear or even plastic in other directions.

Moreover, while the composite's behavior can be considered linear for low deformations, its viscoelasticity and hygroelasticity must be taken into account for higher deformations.