PIEZOELECTRIC HARVESTER TOPOLOGY OPTIMIZATION USING A MULTIPARAMETER MATERIAL MODEL
Breno Vincenzo de Almeida1; Renato Pavanello1
1 University of Campinas
doi:10.20906/CPS/CILAMCE2017-0892
Resumo
During the past decade, methods of reusing environmental vibration energy have been developed, to transform it in useful, electric, energy and store it in batteries or capacitors, especially due to the reduced power requirement of electronic devices, such as cellphones and global positioning systems. This could also contribute to the environment, since batteries would be less used, thus diminishing their chemical waste, as well as decreasing maintenance and energy costs. One of the methods to reach these goals is to increase the energy efficiency of electronic devices, by reusing ambient vibrational waste energy in useful energy, in other words, harvesting it and the piezoelectric harvester is one of the most interesting vibration-toenergy conversion mechanisms. In this article a piezoelectric harvesting device is modelled as a bimorph cantilever beam, with an intermediate metallic substrate, under plain strain hypothesis. The design of the piezoelectric material of the harvester is then structurally optimized using the proposed multiparameter Bidirectional Evolutionary Structural Optimization (BESO) method to minimize an inverse conversion factor. Different penalization factors, one for each physical property of the piezoelectric material, are chosen in order to find a better convergence for the algorithm and to make more stable. Numerical results for the multiparameter analysis are displayed and analysed, in order to study the influence of the harvester's geometry and its different substrate materials on the conversion factor.
Palavras-chave: piezoelectric; harvester; structural optimization