Thermomechanical modelling for fatigue damage of bituminous materials
Résumé
To assess fatigue cracking performances, pavement materials are tested under cyclic loading during fatigue laboratory tests. Fatigue damage is generally assessed using the global specimen stiffness decrease. This classical fatigue life interpretation can be modified by the softening effect of thermal increase due to viscoelasticity which is not real micro-craking induced damage. Here the material is modelled as a thermo-viscoelastic damageable material tested under sinusoidal loading. Both thermal and mechanical aspects and their coupling are taken into account leading to a complete constitutive modelling. Simulations are performed on cylindrical tension compression tests assuming a purely radial heat transfer. Comparison with temperature measurements and the global stiffness evolution lead to a good agreement between the model and experimental data. This approach points out the importance of thermal effects in fatigue tests and the limitation of classical approaches when thermal effects become important.
To assess fatigue cracking performance, pavement materials are tested under cyclic loading during fatigue laboratory tests. Fatigue damage is generally assessed using the global specimen stiffness decrease. This classical fatigue life interpretation can be modified by the softening effect of thermal increase due to viscoelasticity which is not real micro-cracking induced damage. Here the material is modelled as a thermo-viscoelastic damageable material tested under sinusoidal loading. Both thermal and mechanical aspects and their coupling are taken into account leading to a complete constitutive model. Simulations are performed on cylindrical tension compression tests assuming a purely radial heat transfer. Comparison between the model and experimental data regarding temperature measurements and the global stiffness evolution lead to a good agreement. This approach points out the importance of thermal effects in fatigue tests and the limitation of classical approaches when thermal effects become important.
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