什么是 Rheology, brittle and ductile behaviour？

The rheology of a material is the way it deforms and flows under stress: the relation between stress, strain and the rate of strain. A rock shows brittle behaviour when it deforms by fracture or by sliding on fractures, on discrete surfaces, with a sudden loss of strength; it shows ductile behaviour when it deforms permanently and continuously through its volume, without losing its cohesion.