03 Décembre – Soutenance de thèse - Gilberto Fontecha Dulcey
10 h45 Amphi 21 - ESTIA (Bidart)
Parametric, reduced and multiscale model for the interactive optimization of laminated composite structures.
The design process of laminated composites faces a major challenge: while an engineer designing a metallic based mechanical product is mainly focusing on the development of a shape that will guarantee a specific behavior, the engineer for whom the design problem is that of a composite based product must, find the best combination of shape-material structure. So, also, he must simultaneously create a material and the product topology. The number of design solutions can be huge since the solution space is very large.
Standard CAE systems (CAD, Finite Element Simulation) do not offer to the designer an approach to explore these solution spaces efficiently and interactively. A new numerical procedure is proposed to allow engineers to handle each design parameter of a laminated composite structure, either the scale at which it is relevant.
First, the Parametric and Reduced Behavior Model (PRBM) is a separated model that enables reasoning based on
1- A multi-scale approach: the mechanical parameters of the structure are explicitly described as coming from the material quality of each fiber, the matrix, each layer and the topology of the laminate,
2- a multi-physical approach: independently the mechanical behavior of each layer and each interface is processed, next, to lead to the behavior of the laminate. Some situations of static and dynamic behavior are studied. In the case of dynamic behavior, the creeping becomes a conceptual issue.
The PRBM has been developed by mixing a PGD numerical method and the fractional derivative. Integrated in the Parametric Knowledge Model (PKM with other model of knowledge, it makes the base of a design support approach.
Secondly, a method mixing fractional derivatives and the PGD method allowed the realization of the PRBM. Integrated into a Parametric Knowledge Model (PKM) with other expert knowledge models, it makes the basis of an interactive method of design support.
The PKM is processed by an evolutionary optimization method. As a result, the designer can interactively explore the design spaces. To qualify our models and our PRBM, we study 2 problems of design of laminated composite structures. The solutions determined are qualified with regard to finite element simulations or according to an empirical approach.