Optimisation structurale par éléments finis d’un gousset en matériaux composites et de sa caractérisation par tests mécaniques

Abstract

Nowadays, mass reducing of structural parts is a key factor in aeronautical innovation. Moreover, there is a lot of interest regarding the unidirectional dry thin plies, as they provide better mechanical behavior for laminates in general. Used in composite optimization, they get another kind of interest: indeed, as they are thinner, they enable more ply drop off and as a consequence more design freedom. Thus, the lay up optimization of parts made in such composite material leads to an interesting mass loss. The objective of this project is to develop an optimal infusion process for UD dry thin plies, to characterize the material, optimize a current part in structural reinforcement: “a 2D corner gusset in composite”, and finally infuse this part, test and validate the optimization. The project was divided in 4 steps. First of all, the infusion process was optimized and developed in order to overcome the lack of permeability in unidirectional dry thin plies. Then, once the infusion made possible, mechanical characterization of the material was determined, by mechanical tests, comparison to the literature and calculus. All the data obtained were required to define a finite element model. This model was used for the third step of the project: the composite optimization in three phases -with the Altair software- of the 2D corner gusset, answering a tension load case and a compressing one. Finally, the optimized part was infused and tested, according to the two load cases in order to observe the bearing and the buckling failures. A simulation of the tests was achieved to evaluate the composite optimization of the gusset. The optimization of the gusset made of unidirectional dry thin plies resulted in a reduction of the order of 30% compared to a gusset with the same maximum thickness, but constant over it surface. Furthermore, mechanical tests have shown that the optimized gusset has better postbuckling and bearing mechanical behavior compared to an aluminum gusset for two thirds of the mass of the aluminum gusset.

Date	24 Aug 2021
Original language	French
Awarding Institution	École de technologie supérieure
Supervisor	Simon Joncas (Supervisor) & Sébastien Gordon (Co-supervisor)