In a material that obeys Hooke's Law, the initial uniaxial elastic response is linear with stress and strain coupled through Young's modulus, E, such that: Stress = E (Strain). Young's modulus is, ...

These are nonlinear elastic materials for which the slope of the stress-strain curve, (ds/de) e, is the strain dependent elastic modulus, the Tangent modulus. Elastic deformation continues until the ...