ESR 2 : Firas Bejar

PhD title :

Geometry and mounting optimisation of lightweight gear transmission components

Firas Bejar

Recruiting universityEcole Centrale de Lyon (FR)
Academic supervisorsDr. Joël Perret-Liaudet,
Dr. Olivier Bareille,
Prof. Mohamed Ichchou
Industrial partnerPowerflex (IT)
Industrial supervisorDr. Mauro Fontana
SecondmentsVibratec (FR), ENIS (TN)
Start date 01/11/2020
Duration36 months

Short Bio

Firas Bejar is a material scientist & engineer who graduated from the National Engineering School of Sfax. With a versatile arsenal of technical and social skills, he was able to deliver a valuable contribution in multiple projects associated with aerodynamics, finite element analysis, vibroacoustics, and material optimization of lightweight structures in companies like AVIONAV and ATI industrial services.
He was also the lead coordinator of the world’s biggest social entrepreneurship movement for youth at his local university as a Campus Director within the Hult Prize Foundation in partnership with the United Nations.

Through this project, Firas aims to acquire a deeper understanding of the field of structural dynamics within a qualified and cooperative network that empowers him to make a huge leap of faith in his career either by taking part in state-of-the-art projects or by launching his own eco-friendly technological start-up.

Project description

The main objective of this ESR is to optimize the components geometry and assembly conditions of a standard gearbox with the additional constraint of maintaining the NVH properties and efficiency of the transmission. The effects of typical reducing the weight by modifying the geometric and assembly properties of the transmission will be assessed. The geometry and assembly optimization strategy takes into account control of the whining noise without reducing the efficiency of the gearbox. The promising question of decoupling the gear transmission parts and its influence on the overall performance will be also deeply considered. Some specific points to be considered further in this work are: Prediction of the sources of excitation at tooth contact induced by the meshing process; Setting-up a tool to calculate the deterministic global dynamics of the gearbox with very low computation time; Validation on an existing gearbox; Setting-up a cost function based on gearbox weight and the optimization constraints; Selection of a metaheuristic to provide adequate solutions to the optimization problem with a reasonable computation time for industrial applications.


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