Soutenance de thèse : Fabien DUBOIS
Tribological and vibratory approaches for amplified piezoelectric inertia motors.
Doctorant : Fabien DUBOIS
Laboratoire INSA : LaMCoS
Ecole doctorale : ED162 : MEGA
SPA are amplified piezoelectric inertia motors. They operate by converting asymmetrical vibrations into µ-displacements by means of friction, through stick-slip. These vibrations and this friction raise issues related to wear and noise. So, the present work investigates both the tribological and vibratory behaviours of these motors. First, a pin-on-pad tribometer, actuated by a SPA, was developed. It led us to observe, in-situ and in operation, interfacial solid flows: the 3rd body. These direct observations carried out in conjunction with post-mortem analyses resulted in decrypting the tribological solicitations and in increasing by ten the lifetime of the motors. Second, numerical and experimental considerations have been proposed to better grasp the vibratory behaviour of SPA. The existing lumped model was modified to a more versatile hybrid lumped-FEM model. The experimental tests made it possible to determine the main acoustic contributor and to reduce the noise level by sixteen dBA. Finally, this dual - tribology/vibratory - approach provided a better understanding of the SPA intricacies. In particular, it led to develop innovative structures such as a motor with three degrees of freedom and two rotary motors.
Amphi Claude Chappe (Bâtiment Claude Chappe, TC)