Time dependent behavior of the members of bonded composite material structure
The main topic of this thesis will focus on analysis of the mechanical time-dependent behavior of composite/concrete and concrete/steel structures. The analysis and resolution of the problem will be carried out at two levels: the interface and the structural element. The connexion between the different parts will be by bonding or/and by bolting. Attention will be particularly focused on the time-dependent behavior (aging, creep, relaxation, durability…).
The effect of aging will first be studied at the scale of the interface (push-out tests, double-shear…) by natural and accelerated methods of aging. The damage mechanisms will be identified and, in association with numerical simulation, then the results will be used to deduce the states of stress not to be exceeded to ensure the durability of these structures.
At the same time, from a structural point of view, it will be necessary to improve the existing knowledge of the instantaneous behavior of bent elements taking into account the influence of biaxial effects, for example due to out of plane loading. Indeed, the precise knowledge of the state of stress under short term load is essential to determine the long-term behavior. Then, the response under long term moderate load will be established within the context of linear viscoelasticity using methods of calculation with increasing precision of: effective module, integral method, incremental method. The aging and the possible deformation of shrinkage will be gradually integrated into the process.
All the results attained will be validated experimentally at the scale of structural elements under instant load and the coupled effects of long-term load and aging, on the basis of existing test results obtained in the Laboratory.
- Bruno JURKIEWIEZ
- Nadège REBOUL
Beginning and end of the PhD thesis
01/10/2015 – 01/09/2018