Question

Difference between unit cell and representative volume element

Answer 1

RVE and unit cell are actually the same. They both refer to a material point of interest where the local behavior is simulated. There is a slight catch, though. A RVE is supposed to be "representative", i.e. the volume element must be representative of the entire material. A unit cell on the other hand does not have to be representative. For e.g. in the case of polycrystal simulation in metal plasticity, a unit cell built up of 100 grains is assumed to be representative of the material behavior and is hence a RVE, whereas a unit cell with 10 grains, for e.g., is not representative and is referred to as a unit cell only and not as a RVE.