Little is known about the behavior and durability of strengthening systems applied on concrete substrata and the possible loss of performance due to the degradation of the intervening materials by the structure’s natural aging process and exposure of the externally strengthened elements to aggressive environments. In this context, the present work presents an experimental analysis of the behavior of reinforced concrete beams strengthened with Carbon Fiber Reinforced Polymer (CFRP), applied according to the Externally Bonded Reinforcement (EBR) technique, maintained in a laboratory environment (indoor and protected) or exposed to weathering (outdoor exposure). In addition, specimens of the intervenient materials were also molded and exposed to the same environmental conditions as the beams. The results indicate that weather-exposed epoxy adhesives present reductions up to 70% in their mechanical properties after exposure, while the CFRP composite properties remain similar. It was also found that the strengthening system provided 50% and 28% increments in the load-carrying capacity and stiffness of the elements, respectively. However, the tests conducted after 6 months of weathering exposure showed a 10% reduction in the load-carrying capacity of the strengthened elements.

Na indústria automobilística, tanto pelo fator de ganho de vantagem competitiva quanto por força de exigência normativa (normas VDA 6.3, por exemplo), as empresas vêm cada vez mais adotando as auditorias de processo como forma de identificar oportunidades de melhoria em suas atividades. Diferentemente das auditorias realizadas a partir de normas de gestão da qualidade, como a ISO 9001:2000, a auditoria de processo é realizada por um profissional com conhecimentos específicos do processo a ser auditado, desempenhando não apenas o papel de identificação de não-conformidades, mas também atuando como consultor na melhoria de cada etapa do processo. Esse artigo apresenta um estudo de caso sobre a aplicação e os resultados obtidos com a auditoria de processo, com base na norma VDA 6.3, na área de armação de carrocerias em uma montadora de automóveis. Pela análise dos dados coletados, conclui-se que as auditorias de processos são eficazes na detecção, prevenção e eliminação de não-conformidades no processo produtivo.

Non-linear energy harvesting system was project to enhance interaction to ambient vibration that is wide band and low power which difficult the design for resonant solution. To improve efficiency of a non-linear design it was project a control system based in optimal linear control (OLC). Applying numerical evaluations it was possible to analyze the kinetic energy from the system as also the resulting output voltage. As main result there was a considerable increase of output voltage due controlled system in comparison to open loop for the same excitation.

Dynamics of a non-linear energy harvesting is affected by excitation source and to explore efficiency it is necessary to understand which region offers more energy and the influence of a forced periodic vibration related to ambient non-ideal and power source. A bistable Duffing oscillator coupled to piezoelectric layers and electric load configuring a non-linear energy harvesting is excited by periodic resonant vibration and the system behaviour and energy availability is compared to non-ideal excitation. The chaos via Lyapunov exponent were determined and Runge-Kutta forth order was applied to determine displacement, velocity, phase portrait and output voltage. As main conclusion it was possible to identify a more efficient coupling of cantilever configuration to non-ideal power source than resonant periodic excitation. Considering the kinetic energy available for the coupled system to be converted into electricity it was possible to verify an increase around then times of energy offered to the harvesting system from non-ideal vibration compared to periodic resonant

Harnessing energy from environment requires maximum interaction between harvesters and energy power source. Since available energy in natural system is random and small power, harvester must increase their capability. Is known that resonant solution for energy harvesting devices can improve their performance, however projects are limited for a small time matching natural frequency offered from environment vibration. To enhance energy harvesting result it is propose a controller to driven harvester to maximum vibration interaction to the power source. This study is based in numerical evaluation. The proposed controller regards Linear Matrix Inequalities (LMI) H∞ approach. As main result it is noted a considerable increase of system vibration energy available for harvesting.