Browsing by Author "PEREIRA, RUI ALEXANDRE FERNANDES"
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- Desenvolvimento e análise de um atuador de elastómero dielétrico reforçado com fibrasPublication . PEREIRA, RUI ALEXANDRE FERNANDES; Fonseca, Elza Maria MoraisThis dissertation aims to investigate the influence of fiber reinforcement on the behavior of dielectric elastomer actuators and to establish a reproducible methodology for their fabrication, characterization, and modeling. The silicone elastomer Ecoflex 00-10 was selected due to its high flexibility and similarity to other hyperelastic materials used in soft robotics. Mechanical characterization was conducted through uniaxial tensile tests, which enabled the calibration of constitutive models. The Mooney-Rivlin model achieved the best agreement with the experimental data. A comprehensive fabrication protocol was developed, encompassing mold design and auxiliary structures, yielding a success rate of 66,7% for actuators without fibers and 58,8% for actuators with fibers. Analytical and numerical models were implemented to predict electromechanical behavior, with numerical simulations proving more accurate. In contrast, the analytical approach showed limitations due to oversimplifications in boundary conditions and fiber constraints. Experimental evaluation demonstrated that fiber reinforcement can be advantageous under specific conditions. At low-load regimes, reinforced actuators exhibited improved efficiency, with a 53,2% increase, and greater displacements, with a 15,8% improvement, compared to actuators without reinforcement. Conversely, under higher loads, actuators without fibers outperformed the reinforced ones, achieving 45,6% higher efficiency and supporting weights of up to 43 g, equivalent to 72 times their mass. Cyclic tests confirmed the repeatability of performance, and a maximum energy density of 1594,5 J/m³ was obtained, comparable to values reported for other soft actuators. The findings demonstrate that fiber reinforcement significantly alters electromechanical interactions, enhancing performance in low-load conditions while limiting it under demanding loads. This work establishes a solid methodological basis for future studies. It highlights potential optimization paths, including improvements in the fabrication process, reduction of elastomer thickness, exploration of alternative geometries such as multilayer or folded configurations, and the incorporation of materials with higher dielectric permittivity.