Experimental investigation of the stress–stretch behavior of EPDM rubber with loading rate effects

The tensile stress–stretch behavior of an ethylene–propylene–diene terpolymer (EPDM) was experimentally investigated, both in a quasi-static stretching rate range (<0.4/s) with a conventional material test machine and in a dynamic stretching rate range (2800/s–3200/s) with a split Hopkinson tension bar (SHTB) technique. Experimental data were then analyzed using the Ogden and Roxburgh’s idealized Mullins effect modeling theory. Results show that the stress–stretch behavior is significantly dependent on stretching rate and the Mullins effect exists under dynamic loading. Furthermore, stretching rate only affects the material properties. The degree of damage in a stretched specimen is a function of only the maximum stretch ratio the specimen experienced.