Desenvolupament de sensors antena dins de microcanals a través de metall líquid i recerca de precursors en la fractura d'engranatges basada en la regla de dany acumulatiu lineal

Abstract

This thesis introduces the design, fabrication and preliminary validation of flexible sensors based on microchannels containing liquid metal, created for the early detection of gear damage with aerospace applications in mind. The research is framed in a context where there have been recent incidents with a certain type of turbofan engine, equipped with a gearbox, and the clear limitations of traditional structural health monitoring systems, that often show a lack of sensitivity or responses that are too slow to act on upon the appearance of critical defects. Upon this scenario, the work proposes the use of microfluidic structures fabricated with PDMS and SU-8, materials that combine flexibility, chemical compatibility and stability, and used together are specially fit to be integrated in mechanical components with complex geometries. The fabrication process includes advanced techniques such as laser-assisted printing to obtain precise patterns, plasma bonding to acquire strong sealing, and the controlled injection of liquid to get a good reading on the vibrations that happen around the circuit. These methods have achieved very good dimensional precisions, within the 2-3% margin that was established on the original design. The first experiments, both on vibration and fluid circulation, have confirmed that the integrity of the device's structure is sound, and at the same time also showed several relevant parameters to take into account for future testing, such as sealing quality and improving of the injection methods. When establishing a Health monitoring System that is at the same time light-weight, scalability and high adaptability, this research contributes to setting camp on future Smart Gear Systems, created to monitor in real time the deformation and cracks appearing in environments such as gearboxes. Besides aerospace applications, this technologies have a very wide field of potential in sectors such as automotive or industrial machinery, offering an innovative and versatile focus on diagnosis and prevention of cracks on environments that pose great operative requirements.

Outgoing

12 - Producció i Consum Responsables

9 - Indústria, Innovació i Infraestructura