Fig. 3. (A) Conditioning of a particle-reinforced rubber specimen stretched to an extension ratio of 3. (Extension ratio is current specimen length divided by initial length.) The stress–strain curves, upon extension and retraction, exhibit `stress softening', which is called the Mullins effect. This softening diminishes as the number of loading cycles increases. Plot is reprinted from Dorfmann and Ogden (Dorfmann and Ogden, 2004), copyright 2003, with permission from Elsevier. (B) Stress–strain curves of a brown alga, Egregia menziesii (Turner) Areschoug, for two cycles of extension and retraction. These curves also exhibit stress softening, with lower maximum stress reached in the second cycle. In addition, for both A and B, viscoelastic loading–unloading loops decrease in size with cycling.