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Dynamics of Architectured Structures and Materials for Vibro-acoustics
Our D.SMART team undertakes research in the field of structural control, especially in the DEMO1 of LABEX ACTION (focused on aspects related to structural health management and vibroacoustic control).
The team’s objectives are based on the use of architecturing strategies (periodicity, gradients, but also liaisons and junctions for the production of structures for vibroacoustic control and the use of materials with thermo- (or even electro-) mechanical couplings in order to pilot their behavior.
The theme is thus perfectly integrated into the department’s focus area “Structures: integration and functionalization.
Goals and Research Areas
The main challenge currently addressed concerns damping control through architecturing. To achieve the team’s objectives two parallel pathways are envisaged:
- Passive strategy: the team obtains initial results relative to the tuning of the damping properties of composite structures by temperature through the use of a core made of shape-memory polymer. The team plans to pursue this path in order to refine the behavior of this type of system, and to, in the end, possess a device enabling precise control of the damping level in structures.
The strategy is based on the use of periodic devices at various scales, with possible extension to gradient media.
- Active pathway: The investigations using this strategy will be undertaken in close contact with the team of Y. Le Gorrec (AS2M Department) to benefit from their experience in automatic control. This second pathway is at the heart of LABEX ACTION, aimed at practical production of a demonstrator defined in the DEMO1 program.
Investigations combining the two approaches have also been undertaken, especially to pilot the damping via pre-stress effects in elastomeric materials.
The applicability and efficiency of architectured solutions in producing adaptive structures remains to be demonstrated. The team’s objective is to provide an integrated design approach, from the basic cell or material to the (smart) structure, by way of development when possible, or through modeling or characterization. The ambition here is, in the long term, to attain integration and development of demonstrators.
- Development of tools that will help to furnish models adapted to different types of stress the system will undergo over the course of its life (static, dynamic, shock, thermal, electric, etc.);
- Development of characterization tools for determining, over a wide range of parameters, the properties of the structures to be developed (in collaboration with the T2DC, PMMCM teams);
- Development of correlation tools that take into account the multiphysics nature of the phenomena under consideration (in collaboration with the V3MQI team);
- Analysis of the robustness of models being developed, to ensure that at no stage of the process (model development, parameter identification, use in a structure model), does any sensitivity issue make the developments unusable (in collaboration with the V3MQI team);
- Large-scale development of applications making use of adaptive structures: concept of the eco-compatibility and recyclability of the proposed solutions.
Implementing our work
Investigations undertaken on this theme naturally call for collaboration with other teams.
Within the Applied Mechanics Department interaction among teams is frequent:
- first of all with the V3MQI team, when taking into account the aspects of sensitivity and uncertainty analyses (a great many members of the personnel work on both of these themes),
- with the T2DC team as a part of the DEMO1 program of LABEX ACTION (propagation of sound waves for SHM, postdoc in progress),
- with the MEMS team, too (design and production of CMUT-type devices on polymer substrate for the development of a conformable and active acoustic skin; postdoc in progress), and
- with the PMMCM team for characterization of materials.
At the FEMTO-ST level, collaboration takes place on aspects of periodic structures and phononic crystals, as well as on active vibroacoustics, with the teams of A. Khelif (MN2S) and Y. Le Gorrec (AS2M), respectively. Also, a project is currently taking form with the ENERGY department and the team of Y. Bailly on the T2DC theme concerning damping control in biocomposite structures through temperature piloting.
On the national level, the team collaborates principally with LTDS (laboratory of tribology and systems dynamics) (M. Collet, M. Ichchou) and will continue with HCERES “Metavibro (EC Lyon, U. Maine, INSA Lyon, ENSMM, CNRS) beginning in 2016, associating the activities of 5 UMR and an EA on the characterization and optimization of metacomposite materials used to control the vibroacoustics of complex systems. In addition, collaboration is in progress with the UTBM (Y. Meyer), the LAUM (C. Pézerat), the UTC (N. Dauchez) and the UHA (G. L’Hostis).
Internationally, collaborative projects are now under way:
› USA: Georgia Tech (K. A. Cunefare, M. Ruzzene, Atlanta, Georgia, USA): periodic meta-materials, with K. Cunefare as guest researcher (2 months) in 2013, Project H2020 ITN EJD in progress;
› UK: University of Bristol (Prof. F. Scarpa) : architecturing of composite structures, particularly auxetic structures; F. Scarpa hosted Kévin Billon, PhD., student from FEMTO-ST, from January to June, 2015; Project H2020 ITN EJD in progress;
› Brazil: Instituto Tecnológico de Aeronáutica (Prof. D. Alves Rade): adaptive periodic structures; co-tutoring in progress (Leandro Rodrigues Cunha, begun in September 2014), funded by the Brazilian program “Sciences Without Borders
› Canada: Université de Sherbrooke (Prof. N. Atalla): adaptive foams with periodical inclusion; co-tutoring in progress (Ahmed Abbad, begun in September, 2014), funded by the Canadian program NSERC;
› Switzerland: EPFL (Prof. H. Lissek): currently under contract (Aircelle/EPFL/FEMTO-ST), development of a noise control strategy for active nacelles.