J.R.F. Arruda, University of Campinas.
Manipulating elastic waves aiming at reducing vibration and noise: band gaps, metamaterials, and topological modes
The most simple structural element, the elementary rod, is used to introduce the basic concepts of wave propagation in periodic structures. We show that, by just ”wrapping around” a finite periodic structure, it is possible to compute a discretized dispersion diagram using standard modal analysis tools. We also show that a spatial state-space formulation can be used to model spatially varying one-dimensional waveguides. Recent results on one- and two-dimensional shape optimization based on spatial Fourier coefficients, including optimizing for an improved sound transmission loss, are presented. The effects of manufacturing variability are investigated using frame structures. Finally, the use of feedback actuation to create non-Hermitian, non-reciprocal systems, which exhibit localized modes that are topologically protected, is addressed. Other investigations on topological behavior are also reported. As a conclusion, the actual potential for industrial applications of acoustic metamaterials are discussed.
J. Peeters, ZF Wind Power.
Empowering a sustainable future with continuous innovation in wind turbine powertrains
Global climate targets and the increased ambition to be independent from imported fossil energy accelerate the energy transition in which renewable energy - such as wind - plays a crucial role. This evolution urges continuous innovation to further increase competitiveness of wind energy as a power source. As a technology driven developer and supplier of wind turbine powertrains, ZF is taking a leading role in this evolution. This article describes recent achievements in the development of new technologies and products contributing to a lower cost of wind energy. One focus point is the combination of advanced simulation models and testing, enabling a more compact and reliable gearbox platform product. Another challenge is the optimization of this product for the sound performance of the wind turbine system. In addition, the benefits of digital technologies are highlighted: technologies that enable easy access to large amounts of data which can be processed in an automated way.