Effect of the Mullins softening on mode I fracture of carbon-black filled rubbers

Abstract

is an open access repository that collects the work of Arts et Métiers ParisTech researchers and makes it freely available over the web where possible. AbstractThe effect of the Mullins softening on mode I fracture of carbon-black filled rubbers was investigated experimentally. Large specimen of NR and SBR filled with the same amount and nature of carbon-black were submitted to uniaxial tension. Then, single edge notch tension samples were cut along various directions with respect to the direction of preconditioning, and submitted to tension until break. The fracture energy was estimated and compared according to the intensity of Mullins softening already undergone in the direction of crack opening and according to the softening undergone in other directions. The NR shows significantly improved resistance to crack propagation compared to the SBR due to its crystallization ability. For both materials, it was observed that a moderate prestrain has a positive impact increasing the material fracture toughness and that material softening and anisotropy induced by Mullins effect does not show on resistance to mode I crack propagation. Mullins effect filled rubbers Tearing energy crack opening

Critical strain energy release rate for rubbers: single edge notch tension versus pure shear tests

“…While the Griffith analysis was possible for pure shear tests, it was not for SENT ones, and in the latter case the authors proposed an analytical expression for the strain energy release rate based on geometrical considerations. Note that this expression has often been used (Lee and Donovan, 1985;Hamed and Park, 1999;Gherib et al, 2010;Gabrielle et al, 2011;Diani et al, 2015) even out of its range of application. For instance, when the initial notch is larger than a fifth of the specimen width (Aït Hocine et al, 1996;El Yaagoubi et al, 2017), due to the high deformability of rubbers, the specimen may rotate causing some shearing and consequently, mixed mode fracture.…”

Experimental investigation of elastomer mode I fracture: an attempt to estimate the critical strain energy release rate using SENT tests

“…Eq. (1) has been reported in survey on fracture of rubbers [10,13,2], and many authors ( [11,9,6,5,3,4] among others) have applied it directly, conveniently bypassing the fastidious work of running Griffith analysis that demands to break several samples with increasing notch lengths, and calculating the critical energy release rate G c as the energy G at which catastrophic failure is witnessed. Eq.…”