SmaRt Composite StructurE (Project SyRaCuSE) Towards mastering challenges concerning the product lifecycle
Résumé
Since the middle of the 80’s, smart composite structures are announced as being able to revolutionize the industrial world and become a main engine of economic growth. A smart composite structure is a structure combining distributed actuator and sensor networks embedded at the heart of the matter and a command and control unit. The idea is to mimic nature in order to produce industrial composite structures that will adapt their functionality to their environment in a predicted manner. This approach seems attractive with a lot of potential applications: Vibration suppression, non-Destructive Evaluation, Energy Harvesting, Internet of Things... In a way, the smart composite structures are indeed at the forefront of the innovation process in the scientific literature. This is true in particular from a numerical modeling point of view. Concerning the prototypes, these structures remain at the draft stage and are mostly far from the real life industrial applications or mass production. Why does a thick border currently exist between the industrial and research worlds? The answer is of course complex. At first order, the selection of the case studies is from technical analyses and not from user-based analysis. This can limit the development of strongly value-added prototypes. Moreover, the balance between the apparent complexity and the performance increasing could be not good enough for industry organizations. The industrial and financial viabilities are clearly considered unfavorable. This is established without a deep analysis. This paper is focused on the early stage design of a smart composite structure with embedded piezoelectric sensors and actuators. To guarantee the transducers’ efficiency and keep the geometrical and material properties of the host composite structure, several major technical issues are identified as having a strong impact on the manufacturing requirements. It is necessary to :
- Electrically connect a large number of transducers so as to act on the whole structure.
- Make each transducer electrically independent. This is particularly important when developing carbon-fibre-reinforced composite structures which are naturally conductive.
- Perfectly couple the exogenous element with the composite material so as to guarantee the transducers’ efficiency and reduce the risks of delamination or other failures.
- Accurately master the location of the transducers into the structure. This is necessary to create symmetric arrays of transducers and so a highly-symmetric distributed network.
- Limit the “cross-talk” between the different embedded elements.
- Limit the thickness variations due to the piezoelectric inclusions.
- Achieve specific shaped structures (for instance, bi-concave structures) so as to adapt to a wide range of real-life applications.
- Achieve a robust link with the outside structure to provide energy or modify the control law or the behavioural law in real time.