Description of the thesis topic

Context and objective of the project: Energy harvesting devices provide a battery-less solution by scavenging energy from ambient sources and converting them into electrical power. The ability to deliver sustainable power to a biomedical device via energy harvesting is attractive as it reduces battery costs and disposal issues, and the need for complex wired systems. This is relevant to micro-sensors within medical implants. However, current systems are only efficient over a restricted frequency range, and elastic coupling of ultrasonic energy recovery devices can be limited, restricting energy conversion efficiency.

The objective of the PhD is to explore active (mainly piezoelectric, but also magneto- and light-responsive) or passive topological metamaterials (MMs) and / or phononic crystals (PCs) to: (i) guide, confine and trap vibratory energy and (ii) improve electromechanical conversion efficiency for health-related applications. By exploiting (and combining) the properties offered by piezoelectricity and topological protection in MMs and PCs, the main idea is to enhance both absorption of mechanical vibratory energy in the structure and conversion into electrical energy. Active materials can be part of the MMs / PCs structures, with the goal, for example to harvest energy during walking, both from floors and from medical insoles. In parallel, auxetic or highly anisotropic passive MMs / PCs involving local resonances or inertial amplification mechanisms will also be explored.

Work Context

Main tasks and responsibilities: The candidate will work in a collaborative way in the framework of the European project HORIZON-MSCA-DN-[2022] MetacMed (« Acoustic and mechanical metamaterials for biomedical and energy harvesting applications ») under the supervision of Dr. M. Miniaci (IEMN). He / she will develop the design of a topological MM / PC that could be ideally used as an energy-harvesting device. He / she will investigate the manipulation of the dispersive properties of elastic MMs through the integration of functional elements into the unit cell. Specifically, he / she will: (i) develop analytical, numerical, or hybrid methods (integrating FEM and analytical models) to investigate the coupled piezoelectric wave equations satisfying the Bloch-Floquet condition, (ii) understand the mechanics behind the conversion of mechanical energy into electrical energy through active elements; (iii) participate into the realization of auxetic MM-based insoles with energy harvesting embedded device network; (iv) measure the efficiency of the designed device.

Required competences: The ideal candidate should have a master's degree in engineering, physics or similar disciplines. Knowledge of numerical modelling and a strong background in structural mechanics and wave propagation in periodic media is a plus.

Required soft skills: The ideal candidate is able of team playing, of rigorous reporting to the supervisors, of independent thinking and working in autonomy under assigned tasks and towards specific objectives.

Location: The Institute of Electronics, Microelectronics and Nanotechnology (UMR CNRS 8520 - https://www.iemn.fr/en/) is in Villeneuve d'Ascq, near the city of Lille (France). With a total staff of more than 500 people, the institute has a wide range of research activities from physics to materials science, micro and nanotechnology.
Planned secondments: EPFL (8 months) for optimization of the numerical codes and preliminary experimental measurements and University of Messina (3 months) for advanced numerical simulation.

Application: The candidate is asked to provide the following documents (only online applications – CNRS website – will be accepted):
1) A cover letter (2 pages max) explaining why he / she is applying to this position.
2) A detailed CV.
3) Two to three reference letters.

Start date: 01.12.2024 (36 months).

Funding: European project HORIZON-MSCA-DN-[2022] MetacMed (« Acoustic and mechanical metamaterials for biomedical and energy harvesting applications »).

The position is located in a sector under the protection of scientific and technical potential (PPST), and therefore requires, in accordance with the regulations, that your arrival is authorized by the competent authority of the MESR.

Constraints and risks

n/a