The dynamic modeling of complex structures may require to take into account phenomena occurring at very different scales. However, a full refined modeling of this type of structure generally leads to prohibitive calculation costs. Multiscale modeling then presents an alternative solution to this problem, taking into account each phenomenon at the most appropriate scale.
We are interested here in slender structures subjected to mechanical stresses with frictional contacts between the structure and the retaining elements. The behavior of slender structures is in general represented by beam models, but accurately taking into account all the local contact/friction requires massive 3D models.
The originality of the work proposed here is to build an efficient multiscale and multimodel approach between beam and massive models which makes it possible to locally take into account the friction contact of slender structures. We are therefore moving towards the use of local multigrid (or multilevel) methods which naturally allow a non-intrusive multiscale coupling. The accuracy of these methods depends on the choice of transfer operators between scales, which must be carefully defined. It will also be necessary to take into account the incompatibility of the meshes supporting the models on the various relevant scales. Hence, the final model will consist in an enriched beam model taking into account local contact phenomena.
The developed model will be compared with experimental results obtained during test campaigns already carried out, and with reference numerical solutions, of increasing complexity, intended to finely validate the relevance of the proposed multiscale approach.
The strong potential of the targeted multiscale approaches, applied in this subject to the nuclear field, could be exploited by the candidate for other industrial issues such as those of aeronautics or the automotive industry.
This thesis will take place within the framework of the joint MISTRAL laboratory between the CEA and the LMA (Laboratoire de Mécanique et d’Acoustique) in Marseille. The PhD student will carry out the major part of his thesis within the CEA (IRESNE institut, Cadarache) in teams specialized in numerical methods and dynamic modeling of complex structures. The doctoral student will travel regularly to Marseille to discuss with the university supervisors.