Fig. 23.

Within the linear viscoelastic region (bottom left) the storage and loss moduli, G′ and G″, respectively are independent of the applied strain amplitude. The resulting shear stress curve is, therefore, sinusoidal (top left). However, once entering the non-linear region (bottom right), G′ and G″ become dependent on shear amplitude, i.e. G′(γ₀) and G″(γ₀), and the shear stress curve is no longer sinusoidal (top right). This illustrates the different behaviors expected from small amplitude oscillatory shear (SAOS) and large amplitude oscillatory shear (LAOS) experiments. As a note, the distortion of the stress curve in the non-linear region can be attributed to the higher harmonics of G′ and G″. Reprinted with permission from Hyun et al. [388].