Essential work of fracture and viscoplastic response of a carbon black-filled thermoplastic elastomer

Observations are reported on a carbon black-filled thermoplastic elastomer in uniaxial cyclic tensile tests with various maximum strains and double-edge-notched-tensile (DENT) tests with various ligament widths at ambient temperature. It is shown that the stress–strain diagrams in DENT tests measured relatively far away from the ligament coincide with those in tensile cyclic tests on un-notched samples. To describe the viscoplastic response of un-notched specimens, constitutive equations are derived, and adjustable parameters are found by fitting the experimental data. It is demonstrated how the energy stored in a DENT sample under tension can be accounted for in calculations of the specific essential work of fracture.