Tailoring nonlinearity for advanced engineering design



报告题目:Tailoring nonlinearity for advanced engineering design
报告人: Dr. Giuseppe Habib (Budapest University of Technology and Economics)
The analysis of linear dynamical systems is significantly simpler than that of nonlinear ones. This brought engineers and practitioners to see nonlinearities as a detrimental phenomenon to be avoided. Confuting this common point of view, in this talk I illustrate how a correct planning of system nonlinearities can largely increase design possibilities, allowing one to attain performance unreachable by linear systems.
Three examples are considered. First, the performance of the tuned mass damper (TMD) is compared to that of its nonlinear counterpart, the nonlinear tuned vibration absorber (NLTVA). The design procedure of the NLTVA and its advantages over the TMD are discussed. Second, the exploitation of properly tuned nonlinearity for bifurcation control is presented. Adopting a straightforward analytical procedure, it is shown how a correct design of the system nonlinearity enables one to avoid catastrophic subcritical bifurcations. In the third example, a procedure to retrieve linear properties in nonlinear systems by the addition of intentional nonlinearities is illustrated. An algorithm for the definition of the proper additional nonlinearities is presented, with respect to the enforcement of force-displacement proportionality and invariance of the resonant frequency, two properties satisfied by linear systems, but usually not by nonlinear ones. Finally, the possible practical implementation of theoretical findings in engineering systems is discussed.
The presented problems are tackled analytically with a special focus on design aspects. Results are validated numerically and experimentally.
After completing his MSc degree in Mechanical Engineering at the Sapienza – University of Rome (Italy) in 2008, Giuseppe Habib is enrolled as a PhD student at both the Sapienza – University of Rome and at the Budapest University of Technology and Economics (Hungary), being awarded a double PhD degree in July 2013. The topic of his PhD dissertation includes analysis of stability and bifurcations related to time delay and digitization in active control. From October 2013 to September 2016 he works as a postdoctoral researcher at the University of Liege (Belgium). His research is mainly focused on nonlinear passive means for vibration absorption and control of nonlinearity for mechanical design. In May 2016 he is granted a Marie-Sk?odowska Curie individual fellowship for spending 2 years (starting in October 2016) as a postdoctoral researcher at the Budapest University of Technology and Economics. He is coauthor of 17 journal papers, having collected more than 250 citations (source Google Scholar).