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Bio-energy systems with carbon capture and storage (BECCS) will be essential if countries are to meet the gas emission reduction targets established in the 2015 Paris Agreement. This study seeks to carry out a thermodynamic optimization and analysis of a BECCS technology for a typical Brazilian cogeneration plant. To maximize generated net electrical energy (MWe) and carbon dioxide CO2 capture (Mt/year), this study evaluated six cogeneration systems integrated with a chemical absorption process using MEA. A key performance indicator (gCO2/kWh) was also evaluated. The set of optimal solutions shows that the single regenerator configuration (REG1) resulted in more CO2 capture (51.9% of all CO2 emissions generated by the plant), penalized by 14.9% in the electrical plant's efficiency. On the other hand, the reheated configuration with three regenerators (Reheat3) was less power-penalized (7.41%) but had a lower CO2 capture rate (36.3%). Results showed that if the CO2 capture rates would be higher than 51.9%, the cogeneration system would reach a higher specific emission (gCO2/kWh) than the cogeneration base plant without a carbon capture system, which implies that low capture rates (<51%) in the CCS system guarantee an overall net reduction in greenhouse gas emissions in sugarcane plants for power and ethanol production. [ABSTRACT FROM AUTHOR]

Laminated composite structures suffer from delamination, the detachment of the layers due to the rupture of the fiber-matrix interface, as their principal mode of failure. In contrast to other damages, such as cracks, delaminations are often not visible on the surface, causing late detection and leading to sudden failures. To ensure that laminated composite structures operate flawlessly, precise monitoring methods are required. This work proposes a damage index composed of coefficients obtained from applying a Discrete Wavelet Transform to the mode shapes of a laminated composite beam with the purpose of identifying delaminations. Numerical damages were induced by reducing the stiffness in specific locations in order to simulate different damage cases and then providing data for the coefficient optimization in the damage index. After promising results for identifying damage in numerical cases, the damage index's efficiency was tested with real carbon fiber-reinforced polymer beams. The experimental specimens were manufactured with delaminations induced by embedding non-sticking films between the layers. Again, high quality results in identifying damage were achieved. The damage index proved efficient at locating damage in almost all positions along the beam, just having issues at the free end due to the discontinuity of the signal. The same specimens were subjected to tensile stress below the yield point to obtain the strain fields of the structure through the Digital Image Correlation technique. A Discrete Wavelet Transform was applied to the strain fields, aiming to identify the delaminations. It is important to emphasize that the proposed damage index is a no-baseline method, a method that does not require information about the pristine structure. [ABSTRACT FROM AUTHOR]

Purpose: This work is dedicated to disk brake rotor optimization using parametric and topological optimizations considering three conflicting objectives: mass, temperature variation, and breaking time. The rotor had explicit equations modeled and the Multi-objective Lichtenberg Algorithm (MOLA), which is executable in Matlab®, performed a parametric optimization to find the general rotor design parameters. Several optimization techniques have been developed last few years, however, the ones that have presented better results are meta-heuristics associated with posteriori decision-making techniques. Thus, in this work, this powerful and recently created multi-objective meta-heuristic was applied. The MOLA found more than 3000 solutions and the TOPSIS was used for decision-making. Then, the rotor was designed in the SolidWorks® 3D software and the ANSYS software was applied to perform topological optimization, where more mass was removed and analysis regarding the work stresses was done. To the best author's knowledge, this is the first work to consider multi-objective parametric and topological optimization for this structure at the same time in the literature. A considerable mass reduction was obtained. It was possible to find a rotor weighing only 164.8 g with the lowest safety factor across the entire rotor equals 2.02. Therefore, a rotor optimized with reliable, lightweight, and that allows a low braking time was found. Also, these results show that the methodology used can be applied in other structures with complex parameterization. [ABSTRACT FROM AUTHOR]

AbstractThis paper presents an analysis of a sandwich structure featuring an auxetic core, manufactured through Vacuum Assisted Resin Transfer Molding (VARTM) using carbon-aramid hybrid fibers. The core was 3D printed with polylactic acid (PLA). Experimental testing of the structure provided results for validating a cost-effective numerical model. The response surface methodology identified results for different sandwich panel configurations, revealing that auxetic behavior depends on the core’s adopted configuration. Increasing the fiber-core contact area induces auxetic behaviors. The structure underwent optimization using the Lichtenberg algorithm, yielding models with 40.32% higher failure load, 36.36% higher natural frequency, and over 20% mass reduction. [ABSTRACT FROM AUTHOR]

Abstract Due to the advantages of both the metallic and glass fiber qualities, glass fiber reinforced metal layers are one of the best impact resistant materials. Shape memory alloys have also been thought to be effective materials for equipping the traditional impact-exposed materials due to their high impact damping capabilities. The modal response (natural frequencies, damping, and vibration amplitude) of the laminate composite constructions that incorporate shape memory wires was experimentally investigated in this article. The goal of the current research is to ascertain how the modal responses are impacted by three production parameters: wire diameter, wire location, and wire number. Using an experimental design plan and a central composite design, hybrid specimens were planned. The results showed that the manufacturing variables influence all the modal responses in different proportions. Regarding the innovations in the construction of this type of hybrid composite, this study could be used in the design of mechanical and airspace structures. [ABSTRACT FROM AUTHOR]

This study performs a substantial statistical analysis on the effects of damage characteristics, such as position and severity, on a specific damage metric composed of coefficients obtained from the discrete wavelet transform. The results of the analysis serve as the basis for developing more sophisticated and optimized damage-identifying methods in structural health monitoring. For the methodological procedure, a carbon fiber reinforced polymer beam was numerically modeled using the finite element method where the damage was induced considering a local reduction of stiffness in different positions and levels of severity. The numerical methodology was validated with modal experimental tests. Results obtained through analysis of variance and design of experiments indicated the sensitivity of each factor and the response surface provided the best combination of factors for each response. Knowing the sensitivity and interaction of these parameters is essential for the correct formulation of damage indexes or other techniques in damage identification. The results obtained in this paper can be used as a guideline for engineers when developing new wavelet transform-based strategies for structural health monitoring. [ABSTRACT FROM AUTHOR]

This manuscript has more than 150 papers as a reference about energy absorption of auxetic structures and shows how several authors have approached the subject and how research in this field has progressed. It can be noted from the present paper that additive manufacturing has been an ally of researchers in the samples manufacturing and numerical analysis has also been widely used by the authors. In addition, this manuscript will provide a context for auxetic structures, discussing some cell models. The results obtained here serve as additional guidelines to assist engineers and designers in the development of auxetic structures. [ABSTRACT FROM AUTHOR]

The demands for a high-performance prosthesis include high strength and low weight. This study addresses the optimization of a new tube concept, made of composite material, which makes use of an isogrid and internal layer. For the methodological procedure, a response surface methodology (RSM) was used to define in what quantity, under what conditions and which data should be collected during a given experiment, seeking to satisfy the highest statistical precision and the lowest cost in the response. After RSM analysis, the finite element method was used for structural calculations for each condition of the experiment. The numerical results allowed the creation of a meta-model capable of translating the global structural behaviour. Thus, it was possible to optimize the parameters that were translated as responses applied to a lattice structure by particle swarm optimization and the Lichtenberg algorithm (LA). Comparison of the results demonstrated the good performance of the LA. [ABSTRACT FROM AUTHOR]