Post-Doc : Design of smart dynamical multifunctional structures using electro-active materials

Context

Active material, and more precisely piezoelectric materials are very appealing as they offer the possibility to design smart and multifunctional structures. The word “smart” is related here with the possibility of those structures to react dynamically to their environment and the word “multi-functional” to the fact that several functions can be simultaneously achieved by relying on this smartness ability. One can thus imagine structures able to monitor autonomously their health state (structural health monitoring), to actively control their vibration level (active control), or to provide a haptic or audio feedback to a user… Ceramic piezoelectric materials (PZT) have been widely used in that area but suffers from several limitations that hinder their practical use: their geometries are constrained to simple shapes, they are fragile from a mechanical point of view, and they contain lead which is environmentally not acceptable. Newly developed active materials such as P(VDF-co-TrFE) (Poly(vinylidene fluoride-co trifluoroethylene)) overcome these problems because they can be printed in any form, are not brittle and are lead-free. P(VDF-co TrFE) copolymers thus offer numerous applications opportunities in the smart multifunctional structures context as they can be fully optimized to achieve a set of desired target functions.
The main challenges related with the wide deployment and adoption of P(VDF-co-TrFE) based smart multi-functional structures are:
– their electromechanical properties and their interaction with their host structure are still not well understood and need to be experimentally characterized and numerically modeled
– algorithms for optimizing a whole P(VDF-co-TrFE) network satisfying a set of target functions does not exist and cost functions dedicated to the target functions need to be defined
– this concept of “design for smart functions” approach has never been experimentally demonstrated in a practical real-life scenario

Objectives and research work

The objectives of this post-doctoral position are thus:
1) to perform experiments allowing to quantify the electromechanical properties of P(VDF-co-TrFE) materials and to understand their ability to dynamically interact with their host structure either as actuator or sensors,
2) to develop and validate a numerical model allowing to predict the dynamical behavior a P(VDF-co-TrFE) patch bonded to a host structure in a frequency range up to several hundred of kHz.
3) to design an optimization algorithm along with the associated cost functions allowing to design a P(VDF-co-TrFE) network corresponding to a given set of target functions
4) to validate experimentally on an elementary example the concept of “design for smart functions” by satisfying to targets functions using an optimized P(VDF-co-TrFE) network