Development of a damage viscoelastic model using the thick level set approach to fracture: 1D modeling and comparison to uniaxial tension stress tests on bituminous specimens
Résumé
The present paper deals with the development of a mechanical model coupling damage and viscoelasticity for applications related to fracture in bituminous materials and structures. The behavior of these materials is highly thermo-sensitive and depends on the loading rate. Currently, there is no consensus on a modeling approach able to capture their behavior to fracture for a wide range of temperature and loading conditions. This is an objective of the model developed in this paper. Prior to damage initiation, this one is assumed purely viscoelastic and relies on the spectral decomposition of the creep function and the time–temperature superposition principle for the thermal dependency. Damage is later incorporated in the model on the basis of the concept of effective stress and a damage evolution law postulated at the local level, then regularized according to the thick level set (TLS) approach for the purpose of structural computations. This is the first modeling combining the TLS approach and viscoelasticity. This novel model is implemented in a numerical program in 1D and applied to the simulation of uniaxial tensile stress tests (UTST) carried out on a bituminous material at several temperatures and a given monotonic displacement rate. By defining the critical energy release rate as a function of temperature in the model, the numerical simulations compare favorably with the experimental results for all the tested temperatures, proving the capacity of this model to capture brittleness/ductileness of the bituminous samples depending on temperature. Based on the test simulations, other features of the model are also discussed.
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