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Computational modeling of rupture in rubbery polymers

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2020
Akçören, Berkay
Rubbery polymers, also known as elastomers, can exhibit large deformations that are generally accompanied by inelastic deformations. Owing to their superior mechanical, physical, and chemical properties, elastomers are widely used in a broad range of industrial applications such as car tires, seismic isolators, mechanical membranes, and seals. For these applications, failure prediction is cardinally essential. Therefore, this thesis is concerned with the computational failure analysis of rubbery polymers that exhibit highly non-linear material behavior at large deformations. To this end, we model the rupture of rubbery polymers by using the Phase-Field method, where the conservation equation of linear momentum and the evolution equation for the crack phase-field are solved together. While the former describes the mechanical equilibrium, the latter governs damage evolution in rubber. The material behavior of rubbery polymers undergoing damage is modeled by two distinct approaches taken from literature where the damage-induced degradation in the material affects either the entropic and volumetric part of the energy or the energetic and volumetric part of the energy. Moreover, for the entropic elasticity, distinct constitutive approaches are considered. The different modeling approaches are compared through numerical analyses of benchmark problems involving highly heterogeneous deformations of rubbery polymers undergoing rupture.