Semi-active Vibration Suppression - The Best from Active and Passive Technologies
October 1, 2007 — October 5, 2007
Coordinator:
- Andre Preumont (Univ. Libre de Bruxelles, Brussels, Belgium)
The event is part of the program elaborated for the European Atelier for Engineering and Computational Sciences (EUA4X – Marie Curie program). Some of the lectures will be also available on line.
Please check available Marie Curie fellowships under “Admission and Accommodation”
Scope
Vibration suppression is an important issue in many fields of engineering, ranging from earthquake mitigation in civil engineering structures to sub-micron jitter in precision engineering. Typical critical vibration amplitudes go from meters (e.g. wind response of a cable-stayed bridge) to a few nanometers (e.g. optical telescope, atomic force microscope, wafer stepper in semi-conductor lithography machines).
Passive vibration absorbers have been available for a long time (Den Hartog, 1947) and, more recently, a number of promising applications of active vibration suppression have been developed. Active control brings more performance, but at the expense of more technological sophistication, more cost, less robustness and more energy consumption, and this is why it has found relatively little applications outside the research labs, except in precision engineering.
Semi-active control may remove several of the drawbacks of active control, by combining the robustness of purely passive methods with drastically reduced energy requirements. In many cases, however, it operates as a parametric controller which is strongly nonlinear, and cannot be designed according to classical feedback theory.
Smart (or multi-functional) materials respond to stimuli of multiple physical natures (such as mechanical, electrical, magnetic, thermal, etc…). They can be used for transducers and energy conversion devices (e.g. piezoelectric materials converting mechanical energy into electrical energy and vice versa), but also to modify the constitutive parameters of materials (e.g. magnetorheological (MR) fluids, MR polymers).
This course is intended to offer a comprehensive treatment of the theoretical as well as technological aspects of a wide class of semi-active systems applied to vibration damping and isolation, and a review of current and prospective applications in civil engineering, transportation, vibroacoustics, and precision engineering. The comparison between the semi-active devices and their passive and active counterpart will be stressed all along the course. Related issues such as energy harvesting will also be addressed during the course.
The course will provide ample time for discussion and networking.