Heat source and voiding signatures of Mullins damage in filled EPDM

Nicolas Candau (1) , Oguzhan Oguz (2) , Edith Peuvrel-Disdier (3) , Jean-Luc Bouvard (3) , María Lluïsa Maspoch (1) , Guillaume Corvec (3) , Christophe Pradille (4) , Noëlle Billon (3)

1 UPC - Universitat Politècnica de Catalunya = Université polytechnique de Catalogne [Barcelona]
2 EPFL - Ecole Polytechnique Fédérale de Lausanne
3 CEMEF - Centre de Mise en Forme des Matériaux
4 Mat Xper

The thermomechanical coupling of Mullins damage in filled EPDM has been investigated by analysing the self-heating via Infrared thermography (IR) and the voiding fraction by Digital Image Correlation (DIC). The volumetric strain measured during the rubber deformation is found to be predominantly associated with damage, while thermal dilatation caused by self-heating has a negligible contribution. On this basis, the thermomechanical coupling of Mullins phenomena has been identified by evaluating the strain and time dependence of the following criteria: the tangent modulus, the voiding rate and the heat sources. The tangent modulus that reaches a maximum at the strain transition from a series of cycle to another is found to be an appropriate mechanical signature of Mullin softening. At the same strain transition, both voiding rate upturn and heat source upturn are observed. These signatures suggest the Mullins damage to be mainly associated at high strain rate with the (re)-activation of dissipative cavitation mechanisms, by nucleation of new cavities and/or acceleration of cavities growth.

Mots clés: Rubber damage; self-heating; filled EPDM.

Domaines: Mécanique des matériaux [physics.class-ph]

Nicolas Candau, Oguzhan Oguz, Edith Peuvrel-Disdier, Jean-Luc Bouvard, María Lluïsa Maspoch, et al.. Heat source and voiding signatures of Mullins damage in filled EPDM. Polymer Testing, 2020, 91, pp.106838. ⟨10.1016/j.polymertesting.2020.106838⟩. ⟨hal-03047223v2⟩