Ramberg-Osgood Model

A phenomenological constitutive relation expressing total strain ε as the sum of a linear elastic term and a nonlinear power‑law term — commonly written ε = σ/E + (σ/K)^{1/n} or equivalent parametrizations — that produces a smooth transition from Hookean elasticity at low stress to power‑law plasticity at higher stress for monotonic loading in metals.