Dynamics of Structures

This emerging theme at DMSM (new associate Professor and Engineer recruited in 2007) deals with forecasting methods for the vibrational behavior of structures, especially for helicopters and launch vehicles. In partnership with industrialists, the goal is first to design and qualify new passive and active systems for dynamic control and secondly to apply these techniques to structural health monitoring and diagnostics.

DMSM’s work on dynamic control began in 2004, with Joerg Mueller’s PhD thesis, within the framework of a contract with Eurocopter (Marie Curie intra-European fellowship). This thesis dealt with the active control of stability during gyroscopic flutter on tilt rotorcraft, leading to development of a system based on fly-by-wire flight controls. Victorien Bellœil’s 2006 PhD thesis focused on the general design and optimization of alveolar surfacing materials for passive control of structural vibrations. In both cases, specific models were developed at different scales and validated experimentally. In 2006, a contract involving large bandwidth resonators for dynamic control was signed with CNES. This work led to Amir Shahdin’s PhD work devoted to structural dynamic diagnostics for thin composite structures and Pierre Selva’s PhD dealing with a dynamic equilibration model of the inner ear (international PhD, within the framework of the Aeronautics and Astronautics Doctoral School). These two PhDs will be defended in 2009.

In January 2007, theoretical and experimental studies began at DMSM on intrinsic non-linear dynamics, in cooperation with LGMT (A. Berlioz) and ISAE. Leonardo Sanchez began a PhD in 2008 on embedded rotor dynamics. The creation of an internationally co-directed doctoral program in partnership with the University of Surrey led to Thibault Gouache’s PhD in 2008, dealing with the optimisation of a planetary drilling system, with the primary objective of minimizing mass and power requirements. It is financed by the foundation of École Polytechnique and the European Space Agency. This PhD, realized under co-direction by ISAE and University of Surrey, is supported by the foundation of École Polytechnique and European Space Agency.

Within the context of these studies, a dedicated room for vibrational experiments was set up, with facilities for 2-seat aircraft wing vibration tests, tests on rotating parts and educational experiments for rational, vibrational dynamics.