Un modèle thermo-plastique couplé à l'endommagement pour le béton à hautes températures

Abstract

In this paper a new thermoplastic damage model for plain concrete subjected to combined thermal and cyclic loading is developed using the concept of plastic-work hardening and stiffness degradation in continuum damage mechanics. Two damage variables are used: one for mechanical action and the other one for thermal action. Further, thermomechanical interaction strains have been introduced to describe the influence of mechanical loading on the physical process of thermal expansion of concrete. The constitutive relations for elastoplastic responses are decoupled from the degradation damage responses by using the effective stress concept. This method provides advantages in the numerical implementation. Efficient computational algorithms for the proposed model are subsequently explored and performance of this model is demonstrated with numerical examples.Key words: damage theory, plasticity, thermal, unilateral phenomenon, thermomechanical interaction.