Dielectric elastomers can be used to develop innovative mechatronic actuators (called DEA). In this paper, we consider the optimal control problem (OCP) of transitioning between an actuator's operating states. Fol...
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Dielectric elastomers can be used to develop innovative mechatronic actuators (called DEA). In this paper, we consider the optimal control problem (OCP) of transitioning between an actuator's operating states. Following a model-based approach, a set of discrete-time state equations is derived for the DEA, which satisfy accuracy demands and, at the same time, can be solved efficiently by numerical methods. Due to numerical stiffness, the implicit midpoint rule is chosen as an integration method. Then, we discuss different classes of input signals to be considered in the OCP. In particular, zero-order-hold and first-order-hold parametrizations are compared within the OCP formulation. While we show equivalence of two OCP formulations from the theoretical point of view, numerical investigations show benefits of our proposed OCP model regarding the quality of computed solutions and the robustness w.r.t. initial guesses. Altogether, we derive a numerically treatable DEA optimal control set-up, which can be used for various control tasks.
In this paper, we model the multi-objective optimisation problem for maximising the energetic performance while minimising the damage accumulation in ocean wave energy converters based on dielectric elastomer generato...
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In this paper, we model the multi-objective optimisation problem for maximising the energetic performance while minimising the damage accumulation in ocean wave energy converters based on dielectric elastomer generators (DEGs). DEGs are electrostatic smart-material-based transducers that are cheaper, lighter, and more adaptable to the marine environment than conventional power take-off systems. Because DEGs are prone to electrical breakdown upon cyclic loading, identifying trade-offs between achievable performance and lifetime is currently a crucial research question. Based on some assumptions on the system layout and material properties, and using the methods of Pareto optimisation, we prove that a suitably chosen control strategy can potentially achievez a dramatic reduction in the accumulated damage at the expense of a small reduction in the harvested energy. We further compare the Pareto optimal control solutions with commonly used control heuristics for DEGs, showing that optimal control can provide a reduction in the accumulated damage while preserving (or even improving) the energy performance.
In this paper, structural, electronic, magnetic and elastic properties of two spinels XCo 2 O 4 (X= Tc and Si) were studied for the first time. The computations were adopted using the Full Potential Linearized Augment...
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The development of efficient hydrogen storage solutions is crucial for advancing the commercialization of hydrogen-based energy systems. Solid-state hydrogen storage is emerging as a highly promising method, attractin...
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The development of efficient hydrogen storage solutions is crucial for advancing the commercialization of hydrogen-based energy systems. Solid-state hydrogen storage is emerging as a highly promising method, attracting considerable interest and necessitating in-depth research efforts. This study systematically designs six novel solid-state hydrides: K2LiGaH6, K2LiInH6, K2LiTlH6, Rb2LiGaH6, Rb2LiInH6, and Rb2LiTlH6, using density functional theory (DFT). The objective is to thoroughly investigate their structural, elastic, opto-electronic, thermodynamic, and hydrogen storage characteristics. The dynamical stability was analyzed, and the resulting phonon dispersion curves confirm that these materials are stable. Furthermore, ab initio molecular dynamics (AIMD) simulations confirm the thermal stability of the hydrides at room temperature (300 K), as no structural deformation was observed. The band structure indicates that all materials exhibit indirect band gap semiconducting behavior, with band gap values spanning from 0.3 to 2 eV. Optical property analysis reveals that these hydrides are effective ultraviolet absorbers, with a noticeable red shift in the absorption edge can be observed resulting from the variations of bandgap. All the hydrides demonstrate mechanical stability and exhibit brittle characteristics. The calculated gravimetric hydrogen storage capacities indicate that K2LiGaH6 has the highest capacity at 3.22 wt%, followed by K2LiInH6 (2.60 wt%), Rb2LiGaH6 (2.16 wt%), K2LiTlH6 (1.88 wt%), and Rb2LiInH6 (1.86 wt%), with Rb2LiTlH6 having the lowest value at 1.46 wt%. A decrease in storage capacity is observed when the cationic atom at the Q and M site in Q2LiMH6 is replaced, d
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