RANKINE’s THEORY
MAXIMUM PRINCIPLE STRESS THEORY (or RANKINE’s THEORY) According to this theory, when the maximum principle or normal stress reaches the limiting strength of the material, then it undergoes elastic failure. Since the limiting strength for ductile materials is yield point stress and for brittle materials is ultimate stress, the maximum or principle or normal stress (σ1) is given by σ y σ 1 = ---------- (Ductile materials), Factor of Safety ...