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2014
Conference Paper
Titel
Global optimization of smart lightweight structures
Abstract
Modern vehicles are constrained to lower CO2 emissions and therefore to have reduced mass compared to ancient designs. In order to accomplish that, the replacement of metals by lightweight composite materials is an interesting option, but this can significantly change the NVH behavior of the vehicle, thus requiring new design techniques. In this context, much research has been done in the last decades to understand the so-called shunted systems, which consist of electromechanical transducers, like piezoelectric ceramic transducers, applied to a mechanical structure and connected to an electronic shunt circuit, so as to reduce structural vibrations. Consequently, lightweight design can be combined with the advantages of shunted systems, which can significantly improve NVH characteristics without excessive mass addition. As a promising area of research, this paper presents a methodology for a global design of a smart structure, instead of isolated sub-systems, where different functions of the electromechanical system (host structure, transducers and electronics) are simultaneously optimized. This paper concentrates on numerical investigations of composite materials and focus on semi-active vibration control. In order to show the effectiveness of this method, an initial composite part is improved by shape optimization, regarding its mass, durability, static and dynamic behavior. During this phase, the effective (or generalized) electromechanical coupling coefficient (EMCC), which describes the energy transfer between the mechanical and the electrical systems, is also optimized. Finally, an optimized shunt circuit is connected to the system, showing that high vibration attenuation and high mass gain can be both attained.