Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
(Overhead Presentation): It can be foreseen that as cable-stayed bridges age there will be ever-lasting problems of repair. Additionally, up to now cable bridges show potential endurance impairments resulting from rain/wind induced oscillations. These problems will become more and more serious when visions such as the Messina Bridge with its span width of 3,300 m come to existence. Consequently, engineers need new and modern materials to solve the tasks of the future. In civil engineering, considerations must shift from strength related limits to limit states characterized by the infringement of stability and vibration limits. At present, phenomena such as synchronized vortex shedding, galloping, bending and torsional flutter and parametric excitation more often tend to interfere with the structural behaviour in a detrimental way. Therefore active damping is needed. With high strain electroactive (piezoelectric) actuators strains up to 300 % have been demonstrated. Despite the lack of electrodes for very high deformations macro-actuators based on electroactive materials are under development that will lead - in far future - to autonomous bridges. These bridges will react not only to oscillation generating forces but also to noise. Macro-systems (e.g. passive dampers) will be replaced by active micro-systems with thousands of distributed sensors and actuators. And noise coming from vehicles will be extinguished by active anti-phase 'noise nets'.
(Overhead Presentation): It can be foreseen that as cable-stayed bridges age there will be ever-lasting problems of repair. Additionally, up to now cable bridges show potential endurance impairments resulting from rain/wind induced oscillations. These problems will become more and more serious when visions such as the Messina Bridge with its span width of 3,300 m come to existence. Consequently, engineers need new and modern materials to solve the tasks of the future. In civil engineering, considerations must shift from strength related limits to limit states characterized by the infringement of stability and vibration limits. At present, phenomena such as synchronized vortex shedding, galloping, bending and torsional flutter and parametric excitation more often tend to interfere with the structural behaviour in a detrimental way. Therefore active damping is needed. With high strain electroactive (piezoelectric) actuators strains up to 300 % have been demonstrated. Despite the lack of electrodes for very high deformations macro-actuators based on electroactive materials are under development that will lead - in far future - to autonomous bridges. These bridges will react not only to oscillation generating forces but also to noise. Macro-systems (e.g. passive dampers) will be replaced by active micro-systems with thousands of distributed sensors and actuators. And noise coming from vehicles will be extinguished by active anti-phase 'noise nets'.
Adaptive material systems for civil structures
Adaptive Materialsysteme für das Bauwesen
Meier, U. (Autor:in)
2003
71 Seiten, 53 Bilder
Aufsatz (Konferenz)
Datenträger
Englisch
Material selection requirements for civil structures
| Tema Archiv | 2003
Adaptive base-isolation of civil structures using variable amplification
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Earthquake protective systems for civil structures
| British Library Conference Proceedings | 1995
Adaptive Sliding Mode Control for Civil Structures Using Magnetorheological Dampers
| British Library Conference Proceedings | 2006