Journal articles: 'Mechanical optimizations'

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Vlahopoulos, N., and C. G. Hart. "A Multidisciplinary Design Optimization Approach to Relating Affordability and Performance in a Conceptual Submarine Design." Journal of Ship Production and Design 26, no. 04 (November 1, 2010): 273–89. http://dx.doi.org/10.5957/jspd.2010.26.4.273.

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A multidisciplinary design optimization (MDO) framework is used for a conceptual submarine design study. Four discipline-level performances—internal deck area, powering, maneuvering, and structural analysis—are optimized simultaneously. The four discipline-level optimizations are driven by a system level optimization that minimizes the manufacturing cost while at the same time coordinates the exchange of information and the interaction among the discipline-level optimizations. Thus, the interaction among individual optimizations is captured along with the impact of the physical characteristics of the design on the manufacturing cost. A geometric model for the internal deck area of a submarine is created, and resistance, structural design, and maneuvering models are adapted from theoretical information available in the literature. These models are employed as simulation drivers in the discipline-level optimizations. Commercial cost-estimating software is leveraged to create a sophisticated, automated affordability model for the fabrication of a submarine pressure hull at the system level. First, each one of the four discipline optimizations and also the cost-related top level optimization are performed independently. As expected, five different design configurations result, one from each analysis. These results represent the "best" solution from each individual discipline optimization, and they are used as reference for comparison with the MDO solution. The deck area, resistance, structural, maneuvering, and affordability models are then synthesized into a multidisciplinary optimization statement reflecting a conceptual submarine design problem. The results from this coordinated MDO capture the interaction among disciplines and demonstrate the value that the MDO system offers in consolidating the results to a single design that improves the discipline-level objective functions while at the same time produces the highest possible improvement at the system level.

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Mo, Yu Zhen, and Jia Chu Xu. "Studies on Mechanical Properties and Optimization Model of PI/SiO₂ Nanocomposite Based on Materials Studio." Advanced Materials Research 1049-1050 (October 2014): 54–57. http://dx.doi.org/10.4028/www.scientific.net/amr.1049-1050.54.

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The unit cell models of PI/SiO2 nanocomposite was built by Materials Studio. The stiffness matrix and mechanical properties parameters such as Young modulus, shear modulus, bulk modulus and Poisson ratio of the unit cells were achieved after molecular dynamic (MD) optimizations and calculations. The influence factors on the mechanical properties of nanocomposite were analyzed. Finally, the optimization model was achieved.

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Xu, Haoran, Lingen Chen, Yanlin Ge, and Huijun Feng. "Four-Objective Optimization of an Irreversible Stirling Heat Engine with Linear Phenomenological Heat-Transfer Law." Entropy 24, no. 10 (October 19, 2022): 1491. http://dx.doi.org/10.3390/e24101491.

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This paper combines the mechanical efficiency theory and finite time thermodynamic theory to perform optimization on an irreversible Stirling heat-engine cycle, in which heat transfer between working fluid and heat reservoir obeys linear phenomenological heat-transfer law. There are mechanical losses, as well as heat leakage, thermal resistance, and regeneration loss. We treated temperature ratio x of working fluid and volume compression ratio λ as optimization variables, and used the NSGA-II algorithm to carry out multi-objective optimization on four optimization objectives, namely, dimensionless shaft power output P¯s, braking thermal efficiency ηs, dimensionless efficient power E¯p and dimensionless power density P¯d. The optimal solutions of four-, three-, two-, and single-objective optimizations are reached by selecting the minimum deviation indexes D with the three decision-making strategies, namely, TOPSIS, LINMAP, and Shannon Entropy. The optimization results show that the D reached by TOPSIS and LINMAP strategies are both 0.1683 and better than the Shannon Entropy strategy for four-objective optimization, while the Ds reached for single-objective optimizations at maximum P¯s, ηs, E¯p, and P¯d conditions are 0.1978, 0.8624, 0.3319, and 0.3032, which are all bigger than 0.1683. This indicates that multi-objective optimization results are better when choosing appropriate decision-making strategies.

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Lee, Youngmyung, Yong-Ha Han, Sang-ok Park, and Gyung-Jin Park. "Vehicle crash optimization considering a roof crush test and a side impact test." Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering 233, no. 10 (September 5, 2018): 2455–66. http://dx.doi.org/10.1177/0954407018794259.

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The vehicle performances for the side impact test and the roof crush test are dependent on the side structure design of a vehicle. Crash optimization can be employed to enhance the performances. A meta-model-based structural optimization technique is generally utilized in the optimization process since the technique is simple to use. However, the meta-model-based optimization is not suitable for problems with many design variables such as topology and topometry optimizations. A crash optimization methodology is proposed to consider both the side impact test and the roof crush test. The equivalent static loads method is adopted for the side impact test and the enforced displacement method is adopted for the roof crush test, and the two methods are integrated. A design formulation is defined. The survival distance from the side impact test and the roof strength for the roof crush test are used for the design constraints. Crash optimization is performed for a practical large-scale structure. For conceptual design, reinforcement of the B-pillar is determined by using topometry optimization, and size and shape optimizations are employed for a detailed design to satisfy the design constraints while the mass is reduced.

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Sun, S., Z. Fan, Y. Wang, and J. Haliburton. "Organic solar cell optimizations." Journal of Materials Science 40, no. 6 (March 2005): 1429–43. http://dx.doi.org/10.1007/s10853-005-0579-x.

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Du, Yun Peng, Guo Liang Hu, and Fei Dong. "Study on Structural Design and Optimization Analysis for 2V80 Engine Piston Based on Finite Element Analysis." Advanced Materials Research 753-755 (August 2013): 1188–91. http://dx.doi.org/10.4028/www.scientific.net/amr.753-755.1188.

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According to the experiment of engine bench test and piston's temperature field, the thermal boundary conditions and the mechanical conditions of piston are obtained. Under the condition of mechanical load and thermal load playing, the stress and strain of original engine is simulated and analyzed. Stress concentration and weak structure of original engine is found. The parameter of piston structure is optimized and the optimizations are put forward and analyzed to verify the optimizations' effectiveness. These provide a reference for the digital modeling and numerical analysis to solver engineering problems.

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Xiong, Zhe, Xiao-Hui Li, Jing-Chang Liang, and Li-Juan Li. "A Multi-Objective Hybrid Algorithm for Optimization of Grid Structures." International Journal of Applied Mechanics 10, no. 01 (January 2018): 1850009. http://dx.doi.org/10.1142/s1758825118500096.

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In this study, a novel multi-objective hybrid algorithm (MHGH, multi-objective HPSO-GA hybrid algorithm) is developed by crossing the heuristic particle swarm optimization (HPSO) algorithm with a genetic algorithm (GA) based on the concept of Pareto optimality. To demonstrate the effectiveness of the MHGH, the optimizations of four unconstrained mathematical functions and four constrained truss structural problems are tested and compared to the results using several other classic algorithms. The results show that the MHGH improves the convergence rate and precision of the particle swarm optimization (PSO) and increases its robustness.

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Wan, Zhi-Qiang, Xiao-Zhe Wang, and Chao Yang. "Integrated aerodynamics/structure/stability optimization of large aircraft in conceptual design." Proceedings of the Institution of Mechanical Engineers, Part G: Journal of Aerospace Engineering 232, no. 4 (January 11, 2017): 745–56. http://dx.doi.org/10.1177/0954410016687143.

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The multidisciplinary design optimization is suitable for modern large aircraft, and it has the potential in conceptual phase of aircraft design especially. An integrated optimization method considering the disciplines of aerodynamics, structure and stability for large aircraft design in conceptual phase is presented. The objective is the minimum stiffness of a beam-frame wing structure subject to aeroelasticity, aerodynamics, and stability constraints. The aeroelastic responses are computed by commercial software MSC. Nastran, and the cruise stability is evaluated by the linear small-disturbance equations. A viscous-inviscid iteration method, which is composed of a computational fluid dynamics tool solving the Euler equations and a viscous correction method, is used for computing the flow over the model. The method ensures effective and rapid computation. In this paper, a complete aircraft model is optimized, and all the responses are computed in the trim condition with a fixed maximum takeoff weight. Genetic algorithm is utilized for global optimizations, and the optimal jig shape, the elastic axis positions and the stiffness distribution can be attained adequately. The results show that the method has a value of application in engineering optimizations. For the satisfaction of the total drag and stability constraints, the structure weight usually needs a price to pay. The integrated optimization captures the tradeoff between aerodynamics, structure and stability, and the repeated design can be avoided.

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López, Luis Fernando de Mingo, Francisco Serradilla García, José Eugenio Naranjo Hernández, and Nuria Gómez Blas. "Speed Proportional Integrative Derivative Controller: Optimization Functions in Metaheuristic Algorithms." Journal of Advanced Transportation 2021 (November 3, 2021): 1–12. http://dx.doi.org/10.1155/2021/5538296.

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Recent advancements in computer science include some optimization models that have been developed and used in real applications. Some metaheuristic search/optimization algorithms have been tested to obtain optimal solutions to speed controller applications in self-driving cars. Some metaheuristic algorithms are based on social behaviour, resulting in several search models, functions, and parameters, and thus algorithm-specific strengths and weaknesses. The present paper proposes a fitness function on the basis of the mathematical description of proportional integrative derivate controllers showing that mean square error is not always the best measure when looking for a solution to the problem. The fitness developed in this paper contains features and equations from the mathematical background of proportional integrative derivative controllers to calculate the best performance of the system. Such results are applied to quantitatively evaluate the performance of twenty-one optimization algorithms. Furthermore, improved versions of the fitness function are considered, in order to investigate which aspects are enhanced by applying the optimization algorithms. Results show that the right fitness function is a key point to get a good performance, regardless of the chosen algorithm. The aim of this paper is to present a novel objective function to carry out optimizations of the gains of a PID controller, using several computational intelligence techniques to perform the optimizations. The result of these optimizations will demonstrate the improved efficiency of the selected control schema.

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10

Nowak, M. "Improved aeroelastic design through structural optimization." Bulletin of the Polish Academy of Sciences: Technical Sciences 60, no. 2 (October 1, 2012): 237–40. http://dx.doi.org/10.2478/v10175-012-0031-8.

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Abstract. The paper presents the idea of coupled multiphysics computations. It shows the concept and presents some preliminary results of static coupling of structural and fluid flow codes as well as biomimetic structural optimization. The model for the biomimetic optimization procedure was the biological phenomenon of trabecular bone functional adaptation. Thus, the presented structural bio-inspired optimization system is based on the principle of constant strain energy density on the surface of the structure. When the aeroelastic reactions are considered, such approach allows fulfilling the mechanical theorem for the stiffest design, comprising the optimizations of size, shape and topology of the internal structure of the wing.

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Zhao, Yi, Jianxiao Ma, Linghong Shen, and Yong Qian. "Optimizing the Junction-Tree-Based Reinforcement Learning Algorithm for Network-Wide Signal Coordination." Journal of Advanced Transportation 2020 (February 21, 2020): 1–11. http://dx.doi.org/10.1155/2020/6489027.

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This study develops three measures to optimize the junction-tree-based reinforcement learning (RL) algorithm, which will be used for network-wide signal coordination. The first measure is to optimize the frequency of running the junction-tree algorithm (JTA) and the intersection status division. The second one is to optimize the JTA information transmission mode. The third one is to optimize the operation of a single intersection. A test network and three test groups are built to analyze the optimization effect. Group 1 is the control group, group 2 adopts the optimizations for the basic parameters and the information transmission mode, and group 3 adopts optimizations for the operation of a single intersection. Environments with different congestion levels are also tested. Results show that optimizations of the basic parameters and the information transmission mode can improve the system efficiency and the flexibility of the green light, and optimizing the operation of a single intersection can improve the efficiency of both the system and the individual intersection. By applying the proposed optimizations to the existing JTA-based RL algorithm, network-wide signal coordination can perform better.

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Zhai, Shou, Bo Jin, and Yilu Cheng. "Mechanical Design and Gait Optimization of Hydraulic Hexapod Robot Based on Energy Conservation." Applied Sciences 10, no. 11 (June 3, 2020): 3884. http://dx.doi.org/10.3390/app10113884.

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Minimizing energy consumption is significant for the hydraulic walking robot to reduce its power unit weight and increase working hours. However, most robot leg designs are inefficient due to their bio-mimetic or mission-specific mechanical structure. This paper presents a structural optimization method of the hydraulic walking robot by optimizing its mechanical structure and gait parameters simultaneously. The mathematical model of the total power of the hydraulic hexapod robot (HHR) is established, which is derived based on a general template for designing the hydraulic walking robot. The archive-based micro genetic algorithm (AMGA) is used to optimize the highly nonlinear multi-constraint multi-objective optimizations. In the optimal solution, the energy consumption of the HHR has reduced more than 40% by comparison with the original mechanical structure and gait parameter. Design sensitivity analysis is carried out to determine the regulation of mechanical structure, and a virtual prototype is used to verify the effectiveness of the proposed methods.

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Arasteh, Ehsan, and Francis Assadian. "A Comparative Analysis of Brake-by-Wire Smart Actuators Using Optimization Strategies." Energies 15, no. 2 (January 17, 2022): 634. http://dx.doi.org/10.3390/en15020634.

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Since the automotive industry is shifting towards electrification, brake-by-wire technologies are becoming more prevalent. However, there has been little research comparing and optimizing brake-by-wire actuators in terms of their energy expenditure and response time. This paper investigates the comparison of three different smart brake-by-wire actuators, Electro-Hydraulic Brakes (EHB), Electro-Mechanical Brakes (EMB), and Electronic Wedge Brakes (EWB), first by defining an objective metric and then using both linear and nonlinear optimization techniques. Modeling of the actuators is performed using the bond graph method. Then, the controllers are designed using a robust control strategy, Youla parameterization. After designing the controllers, two types of optimization are performed on the actuators. Optimizations are performed in two ways: 1. by linearizing the plants and optimizing using their transfer functions and 2. by nonlinear optimization of the plants in the closed-loop following a specific clamp force target. The objective metrics or the cost functions for these optimizations are chosen to be the energy usage of the plants during the closed-loop operation, maximum power requirement, and their dynamic responsiveness. Using this optimization framework, we can show a significant improvement in the energy usage of the actuators and slight improvements in their responsiveness. In the end, the actuators are compared in terms of their energy usage for sets of initial and optimized physical parameters.

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Li, Q., Ji Hong Zhu, Y. H. Zhang, and W. H. Zhang. "The Topology Optimization of Ceramic-Resin Composite Structure under Thermal and Mechanical Loads." Applied Mechanics and Materials 341-342 (July 2013): 124–28. http://dx.doi.org/10.4028/www.scientific.net/amm.341-342.124.

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The ceramic-resin composite structure is generally used as the investment casting pattern. Due to the coefficient of thermal expansion (CTE) of resin is higher than that of ceramic, the thermal expansion of the resin pattern will lead to the crack of the ceramic shell during the burnout procedure. Simultaneously, the stiffness of the whole structure should be maintained at a certain level. In this paper, topology optimizations with respect to the cavity configuration of the resin pattern were developed to find out the optimal designs. A method involves the assist element was also introduced to control the rigid displacement of the ceramic shell during the heating procedure. Several optimal designs were presented and the comparison of the objectives respectively before and after the optimization investigated these designs could avoid the crack problem of the ceramic shell effectively.

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Salicio-Paz, Asier, Ixone Ugarte, Jordi Sort, Eva Pellicer, and Eva García-Lecina. "Full Optimization of an Electroless Nickel Solution: Boosting the Performance of Low-Phosphorous Coatings." Materials 14, no. 6 (March 18, 2021): 1501. http://dx.doi.org/10.3390/ma14061501.

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Univariate and multivariate optimizations of a novel electroless nickel formulation have been carried out by means of the Taguchi method. From the compositional point of view, adjustment of the complexing agent concentration in solution is crucial for fine-tuning free Ni2+ ions concentration and, in turn, the mechanical properties of the resulting coatings. The Ni (II) concentration and the pH are the main parameters which help restrict the incorporation of phosphorous into the Ni layers. On the other hand, the stirring rate, the pH and the reducing agent concentration are the most influential parameters for the corrosion resistance of the coatings. Multivariate optimization of the electrolyte leads to a set of optimized parameters in which the mechanical properties (hardness and worn volume) of the layers are similar to the optimal values achieved in the univariate optimization, but the corrosion rate is decreased by one order of magnitude.

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Yin, Jian, Qiang Hao, Yu Liu, Shengfang Zhang, and Zhihua Sha. "Multiobjective optimization of internal and surface structure of high-speed and heavy-duty brake disc." Advances in Mechanical Engineering 14, no. 1 (January 2022): 168781402110704. http://dx.doi.org/10.1177/16878140211070459.

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The brake disc plays a crucial role to keep the stable braking of a high-speed and heavy-duty disc brake. There is always high temperature, brake vibration, and even serious deformation under braking pressure and frictional resistance. To improve brake performance, this paper aims to find new internal and surface structures of the brake disc. An equivalent moving load (EML) topology optimization method for internal structure is proposed. Topography optimization method oriented to displacement and stress control for surface structure is carried out. Multiobjective functions containing thermal-structural coupled rigidity and natural frequency of the brake disc are established in the internal and surface structure optimizations. Internal and surface structures of the brake disc are optimized, and the mechanic properties of the brake disc are improved. Thermal-structural coupling and modal analyses are verified with high-speed and heavy-duty brake working conditions. The results show that new brake disc structures meet the requirements, and the effectiveness of the proposed EML topology optimization and topography optimization methods has been proved.

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Han, Ding, Tang Jin-yuan, Zhou Zhen-yu, and Cui Wei. "Tooth flank reconstruction and optimizations after simulation process modeling for the spiral bevel gear." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 230, no. 13 (June 24, 2015): 2260–72. http://dx.doi.org/10.1177/0954406215592922.

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Tooth flank reconstruction and optimization methodologies after simulation process modeling are presented, in order to provide accurate model and tooth data for digitized design and manufacture of the spiral bevel gear. Firstly, a simulation process modeling utilizing universal machine settings is developed for an initial solid model. Then, due to its poor accuracy, tooth flank reconstruction exploiting the Non-Uniform B-Spline fitting method is carried out. Finally, some tooth flank optimizations are introduced for higher tooth flank precision and accurate tooth data: (1) Overall tooth flank interpolations based on the Energy method; (2) Tooth flank approximation based on the least square (LSQ); (3) Tooth flank parameterization based on the Newton Iteration method. Results obtained from some numerical examples indicate that validation of the proposed approaches and tooth flank form error is significantly reduced.

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Zhou, Chen, Zhijin Wang, and Paul M. Weaver. "Thermal-Mechanical Optimization of Folded Core Sandwich Panels for Thermal Protection Systems of Space Vehicles." International Journal of Aerospace Engineering 2017 (2017): 1–12. http://dx.doi.org/10.1155/2017/3030972.

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The integrated thermal protection system (ITPS) is a complicated system that addresses both mechanical and thermal considerations. An M-pattern folded core sandwich panel packed with low-density insulation material provides inherently low mass for a potential ITPS panel. Herein, we identify the most influential geometric parameters and establish a viable, computationally efficient optimization procedure. Variables considered for optimization are geometric dimensions of the ITPS, while temperature and deflection are taken as constraints. A one-dimensional (1D) thermal model based on a modified form of the rule of mixtures was established, while a three-dimensional (3D) model was adopted for linear static analyses. Parametric models were generated to facilitate a design of experiment (DOE) study, and approximate models using radial basis functions were obtained to carry out the optimization process. Sensitivity studies were first conducted to investigate the effect of geometric parameters on the ITPS responses. Then optimizations were performed for both thermal and thermal-mechanical constraints. The results show that the simplified 1D thermal model is able to predict temperature through the ITPS thickness satisfactorily. The combined optimization strategy evidently improves the computational efficiency of the design process showing it can be used for initial design of folded core ITPS.

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Wu, Wei-Guo, Fu-Rui Xiong, Jian-Qiao Sun, and Yong-Gang Leng. "Dynamic modeling of aircraft landing gear and multi-objective optimization with simple cell mapping method." Transactions of the Canadian Society for Mechanical Engineering 43, no. 1 (March 1, 2019): 80–91. http://dx.doi.org/10.1139/tcsme-2017-0083.

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To study the dynamic characteristics of aircraft landing gear and carry out successive optimizations, a mathematical model of flexible landing gear is established by the Hamiltonian principle. The dynamic model includes a tire force estimation derived from the impact model. Dynamic analysis with the flexible model is then conducted. Stress distribution is obtained from the dynamic analysis, which can be used for fatigue analysis, optimization design, etc. To achieve better dynamic characteristics in terms of vibration reduction, a multi-objective optimization problem is formulated and solved via a simple cell mapping algorithm. Optimal simulations indicate the quality of optimal structural designs. Compared with the baseline structure, candidate optimal designs can improve dynamic performance of fuselage vibration suppression, shock absorber efficiency, and stress settling time. The proposed multi-objective optimal parameter design provides a fast tuning procedure that saves considerable time compared to finite element method-based optimization. In addition, the optimal parameter set provides useful interface information for detailed landing gear structural modeling that serves other analysis purposes.

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Li, H. D., and L. He. "Toward Intra-Row Gap Optimization for One and Half Stage Transonic Compressor." Journal of Turbomachinery 127, no. 3 (January 10, 2005): 589–98. http://dx.doi.org/10.1115/1.1928934.

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Multistage effects on both aerodynamics and aeromechanics have been identified as significant. Thus, design optimizations for both aerodynamic performance and aeromechanical stability should be done in the unsteady multistage environment. The key issue preventing such a procedure to be carried out is the enormous computing time cost of multistage unsteady simulations. In this paper, a methodology based on the single-passage shape-correction method integrated with an interface disturbance truncation technique has been developed. The capability, efficiency, and accuracy of the developed methodology have been demonstrated for a one and a half stage quasi-three-dimensional transonic compressor with realistic blade counts. Furthermore, the interface disturbance truncation technique enables us to separate multirow interaction effects from the upstream and the downstream, which makes it possible to superimpose different rotor upstream gap effects and rotor downstream gap effects on the middle row rotor aerodynamic damping. In addition, a gap influence coefficient approach has been developed for investigation of all the possible gap spacing combinations of M upstream stator-rotor gaps and N downstream rotor-stator gaps. Then the number of cases that need to be computed has been reduced from M×N to M+N, which saved substantial computing time. The optimization analysis shows significant damping variation (∼300%) within the chosen intrarow gap design space. The intrarow gap spacing could have either stabilizing or destabilizing effects so that the stabilizing axial spacing could be utilized to increase flutter-free margin in aeromechanical designs. The current approach also can be used for setting aeromechanical constraints for aerodynamic performance optimizations.

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Céa, Jean, Stéphane Garreau, Philippe Guillaume, and Mohamed Masmoudi. "The shape and topological optimizations connection." Computer Methods in Applied Mechanics and Engineering 188, no. 4 (August 2000): 713–26. http://dx.doi.org/10.1016/s0045-7825(99)00357-6.

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Chen, H., and N. C. Baines. "Analytical Optimization Design of Radial and Mixed Flow Turbines." Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy 206, no. 3 (August 1992): 177–87. http://dx.doi.org/10.1243/pime_proc_1992_206_028_02.

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The optimization of radial and mixed flow turbine design, based on simple one-dimensional aerodynamic principles, is described. The objective is to minimize energy losses by reducing the inlet and exit velocities of the rotor. The procedure is based on the specification of a loading coefficient. Previous work has shown that turbines of this type have loading coefficients that lie in a narrow band, and so suitable values can be readily determined. A more detailed specification of losses is unnecessary for the optimization. Optimizations are described for zero and non-zero inlet blade angles, and zero, positive and negative exit swirl conditions.

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Weber, Tobias A., Jan-Christoph Arent, Lucas Steffens, Johannes M. Balvers, and Miro Duhovic. "Thermal optimization of composite autoclave molds using the shift factor approach for boundary condition estimation." Journal of Composite Materials 51, no. 12 (March 20, 2017): 1753–67. http://dx.doi.org/10.1177/0021998317699868.

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Thermal optimization of autoclave molds is essential to increase part quality, reduce manufacturing costs and increase autoclave capacity. Previous experience-based tooling designs allowed an optimization only after the mold was manufactured and tested. Manufacturing process simulation provides the capability for virtual tooling optimization within the design phase. Thereby, the range of possible optimizations increases and the tooling cost decreases. In order to use manufacturing process simulation efficiently, fast but accurate simulation methods must be available. The so-called shift factor approach was previously presented by the authors. This paper takes up the given approach and explains different influences on mold heat-up and how they can be covered in a thermal tooling simulation on an industrial scale. Proof of the simulation accuracy under realistic manufacturing conditions is provided together with an example of its application.

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Item, Cem C., and Oktay Baysal. "Wing Section Optimization for Supersonic Viscous Flow." Journal of Fluids Engineering 120, no. 1 (March 1, 1998): 102–8. http://dx.doi.org/10.1115/1.2819632.

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To improve the performance of a highly swept supersonic wing, it is desirable to have an automated design method that also includes a higher fidelity to the flow physics. With this impetus, an aerodynamic optimization methodology incorporating the thin-layer Navier-Stokes equations and sensitivity analysis had previously been developed. Prior to embarking upon the full wing design task, the present investigation concentrated on the identification of effective optimization problem formulations and testing the feasibility of the employed methodology, by defining two-dimensional test cases. Starting with two distinctly different initial airfoils, two independent optimizations resulted in shapes with similar features: cambered, parabolic profiles with sharp leading- and trailing-edges. Secondly, an outboard wing section normal to the subsonic portion of the leading edge, which had a high normal angle-of attack, was considered. The optimization resulted in a shape with twist and camber that eliminated the adverse pressure gradient, hence, exploiting the leading-edge thrust. The wing section shapes obtained in all the test cases included the features predicted by previous studies. This was considered as a strong indication that the flow field analyses and sensitivity coefficients were computed and provided to the present gradient-based optimizer correctly. Also, from the results of the present study, effective optimization problem formulations could be deduced to start a full wing shape optimization.

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Tao, Ran, Ruofu Xiao, Di Zhu, and Fujun Wang. "Multi-objective optimization of double suction centrifugal pump." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 232, no. 6 (March 28, 2017): 1108–17. http://dx.doi.org/10.1177/0954406217699020.

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Double suction centrifugal pumps are widely used for water supplying system. In this study, the original design of a double centrifugal pump lacked sufficient head at the design flow rate condition. Therefore, the most important objective was to optimize the design to improve the head. A strategy inspired by “liquid–gas cavitation process” is innovatively used for intelligent global search of better pump designs with both higher head and wider-higher efficiency. This strategy has advantages including flexibility, parallelism, and feasibility on overstepping the local-best. The computational fluid dynamics and artificial neural network are used. It helps this optimization to find unknown points in the non-linear and multi-dimensional searching space, and accelerate the optimization process. Candidates were found after search, and the best one was chosen using Pareto principle. Experimental and numerical studies verify that the optimized impeller meets the requirement of head. The efficiency is also significantly improved with higher best efficiency and wider high efficiency range than original design. The critical cavitation is also improved at design condition. This study provides an effective strategy and a good solution for multi-objective optimization of double suction centrifugal pumps. Moreover, this study provides references for the combination of optimizations with artificial intelligence especially in the pump’s design.

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Yoshimura, Masataka, Masahiko Taniguchi, Kazuhiro Izui, and Shinji Nishiwaki. "Hierarchical Arrangement of Characteristics in Product Design Optimization." Journal of Mechanical Design 128, no. 4 (August 22, 2005): 701–9. http://dx.doi.org/10.1115/1.2198256.

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This paper proposes a machine product design optimization method based on the decomposition of performance characteristics, or alternatively, extraction of simpler characteristics, that is especially responsive to the detailed features or difficulties presented by specific design problems. The optimization problems examined here are expressed using hierarchical constructions of the decomposed and extracted characteristics and the optimizations are sequentially repeated, starting with groups of characteristics having conflicting characteristics at the lowest hierarchical level and proceeding to higher levels. The proposed method not only effectively provides optimum design solutions, but also facilitates deeper insight into the design optimization results, so that ideas for optimum solution breakthroughs are more easily obtained. An applied example is given to demonstrate the effectiveness of the proposed method.

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Batay, Sagidolla, Bagdaulet Kamalov, Dinmukhamed Zhangaskanov, Yong Zhao, Dongming Wei, Tongming Zhou, and Xiaohui Su. "Adjoint-Based High-Fidelity Concurrent Aerodynamic Design Optimization of Wind Turbine." Fluids 8, no. 3 (February 28, 2023): 85. http://dx.doi.org/10.3390/fluids8030085.

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To evaluate novel turbine designs, the wind energy sector extensively depends on computational fluid dynamics (CFD). To use CFD in the design optimization process, where lower-fidelity approaches such as blade element momentum (BEM) are more popular, new tools to increase the accuracy must be developed as the latest wind turbines are larger and the aerodynamics and structural dynamics become more complex. In the present study, a new concurrent aerodynamic shape optimization approach towards multidisciplinary design optimization (MDO) that uses a Reynolds-averaged Navier–Stokes solver in conjunction with a numerical optimization methodology is introduced. A multidisciplinary design optimization tool called DAFoam is used for the NREL phase VI turbine as a baseline geometry. Aerodynamic design optimizations in terms of five different schemes, namely, cross-sectional shape, pitch angle, twist, chord length, and dihedral optimization are conducted. Pointwise, a commercial mesh generator is used to create the numerical meshes. As the adjoint approach is strongly reliant on the mesh quality, up to 17.8 million mesh cells were employed during the mesh convergence and result validation processes, whereas 2.65 million mesh cells were used throughout the design optimization due to the computational cost. The Sparse Nonlinear OPTimizer (SNOPT) is used for the optimization process in the adjoint solver. The torque in the tangential direction is the optimization’s merit function and excellent results are achieved, which shows the promising prospect of applying this approach for transient MDO. This work represents the first attempt to implement DAFoam for wind turbine aerodynamic design optimization.

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Gong, Yunyi, Yoshitsugu Otomo, and Hajime Igarashi. "Multi-objective topology optimization of magnetic couplers for wireless power transfer." International Journal of Applied Electromagnetics and Mechanics 64, no. 1-4 (December 10, 2020): 325–33. http://dx.doi.org/10.3233/jae-209337.

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In this paper, the multi-objective topology optimizations of wireless power transfer (WPT) devices with two different coil geometries are proposed for obtaining the designs with good balance between transfer efficiency and safety. For this purpose, the proposed method adopts the normalized Gaussian network (NGnet) and Non-dominated Sorting Genetic Algorithm II (NSGA-II). In addition, the optimization under the different constraint on ferrite volume is carried out to verify its influence on optimization results. It has been shown that the proposed method successfully provides the Pareto solution to the design problem of the WPT device.

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Antonova, Valeria, Stanislav Alekseev, Aleksei Tarasov, Natalia Scheglova, Oleg Klyavin, and Aleksei Borovkov. "Analysis and use of SIMP method in optimization of a car hood design." E3S Web of Conferences 140 (2019): 04017. http://dx.doi.org/10.1051/e3sconf/201914004017.

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The article shows the relevance of creating digital twins and conducting topological and topographic optimizations as part of improving the physical and mechanical properties of car parts using the example of a car hood. A description of the existing optimization methods is given and the principle of the SIMP method is described. The results of optimizing the design of the hood of the car using this method are presented. We demonstrate that using modern approaches to modelling and optimization of automobile parts makes it possible to achieve targets in the design and redesign, to achieve sufficient structural strength while maintaining or reducing the mass of the original structure. It is shown that modelling allows providing an array of information on the optimized part as soon as possible, as well as reducing the consumption of materials used to create it.

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Mahbod, Mahshid, Masoud Asgari, and Christian Mittelstedt. "Architected functionally graded porous lattice structures for optimized elastic-plastic behavior." Proceedings of the Institution of Mechanical Engineers, Part L: Journal of Materials: Design and Applications 234, no. 8 (May 28, 2020): 1099–116. http://dx.doi.org/10.1177/1464420720923004.

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In this paper, the elastic–plastic mechanical properties of regular and functionally graded additively manufactured porous structures made by a double pyramid dodecahedron unit cell are investigated. The elastic moduli and also energy absorption are evaluated via finite element analysis. Experimental compression tests are performed which demonstrated the accuracy of numerical simulations. Next, single and multi-objective optimizations are performed in order to propose optimized structural designs. Surrogated models are developed for both elastic and plastic mechanical properties. The results show that elastic moduli and the plastic behavior of the lattice structures are considerably affected by the cell geometry and relative density of layers. Consequently, the optimization leads to a significantly better performance of both regular and functionally graded porous structures. The optimization of regular lattice structures leads to great improvement in both elastic and plastic properties. Specific energy absorption, maximum stress, and the elastic moduli in x- and y-directions are improved by 24%, 79%, 56%, and 9%, respectively, compared to the base model. In addition, in the functionally graded optimized models, specific energy absorption and normalized maximum stress are improved by 64% and 56%, respectively, in comparison with the base models.

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Li, Zhongkai, Guangdong Tian, Gang Cheng, Houguang Liu, and Zhihong Cheng. "An integrated cultural particle swarm algorithm for multi-objective reliability-based design optimization." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 228, no. 7 (September 4, 2013): 1185–96. http://dx.doi.org/10.1177/0954406213502589.

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Uncertainties in design variables and problem parameters are often inevitable in multi-objective optimizations, and they must be considered in an optimization task if reliable Pareto optimal solutions are to be sought. Multi-objective reliability-based design optimization has been raised as a question in design for reliability, but the disadvantages of fixed evolutionary parameters, nonuniformly distributed Pareto optimal solutions and high computational cost hinder engineering applications of reliability-based design. To deal with it, this work proposes an integrated multi-objective cultural-based particle swarm algorithm to solve the double-loop reliability-based design optimization. In the inner optimization loop, the cultural space is composed of the elitism, situational and normative knowledge to adjust the parameters for swarm space, and the crowding distance ranking is introduced to update the global and local optimum and control the maximum number of solutions in elitism knowledge. The hybrid mean value method is improved to perform reliability analysis in the outer loop to suit both concave and convex types of performance functions. In addition, the car side-impact and the injection molding machine are chosen as multi-objective reliability design examples to demonstrate the effectiveness of the proposed approach. Simultaneously, results of car side-impact problem are compared with two traditional multi-objective reliability optimization algorithms, i.e., nondominated sorting genetic algorithm and crowding distance ranking-based multi-objective particle swarm optimizer, to assess the efficiency of the proposed approach. The results denote the proposed cultural-based multi-objective particle swarm optimizer is effective and feasible to solve the reliability-based design optimization problems.

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Yang, Wenjia, S. L. Ho, and Shiyou Yang. "A vector wind driven optimization algorithm for multi-objective optimizations of electromagnetic devices." International Journal of Applied Electromagnetics and Mechanics 59, no. 1 (March 21, 2019): 55–62. http://dx.doi.org/10.3233/jae-171186.

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Yang, Fan, Zhufeng Yue, Lei Li, and Weizhu Yang. "Aerodynamic optimization method based on Bezier curve and radial basis function." Proceedings of the Institution of Mechanical Engineers, Part G: Journal of Aerospace Engineering 232, no. 3 (November 28, 2016): 459–71. http://dx.doi.org/10.1177/0954410016679433.

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Aerodynamic design is of great importance in the overall design of flight vehicles. In this study, an approach to aerodynamic design optimization is proposed by integrating Bezier curve parameterization and radial basis interpolation to enable large variation of aerodynamic profile during optimization. The Bezier curve uses the shape of a given airfoil and the radial basis function interpolation is applied to smoothly transfer the perturbation to the mesh in the whole flow field. Using design of experiments technique, the prominent design parameters that significantly affect the aerodynamic performance are determined. Aerodynamic optimizations are conducted for a wing airfoil and a blade airfoil to verify the efficiency of the proposed method. Genetic algorithm is employed in both single-objective and multiobjective design cases. Design results show that the present method can significantly improve the aerodynamic performance due to its capability to handle large shape changes of the airfoil. This work provides a useful and powerful tool to aerodynamic design with applications to various flight vehicles.

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Zhang, Zhi-yong, Xin Liu, Cai-xia Huang, and Da Pan. "Noise source identification for industrial sewing machines based on non-linear partial least squares regression model." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 230, no. 16 (August 8, 2016): 2817–27. http://dx.doi.org/10.1177/0954406215602280.

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This paper introduces an application of non-linear partial least squares for vibro-acoustic regression modeling and for an industrial sewing machine. In the vibro-acoustic regression model, the vibration accelerations of reference points are defined as explanatory variables, while the noise sound pressure of target points is defined as response variables, and the number of explanatory variables is determined initially by a correlation analysis in the time domain. To improve predictive accuracy while a non-linear relationship exists between the explanatory and response variables, the explanatory variables are preprocessed by kernel function transformation. The comparison of regressive noise sound pressure to experimental data indicates that the non-linear partial least squares regression model has high predictive accuracy. Furthermore, the contributions of vibration accelerations to noise sound pressure are analyzed, by which the structure optimizations are guided and practiced. The comparison of noise test results before and after optimization testifies to the effectiveness of the contribution analysis.

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Mashkovtsev, Denis, Wataru Mizukami, Jacek Korchowiec, Anna Stachowicz‐Kuśnierz, and Yuriko Aoki. "Elongation method with intermediate mechanical and electrostatic embedding for geometry optimizations of polymers." Journal of Computational Chemistry 41, no. 25 (July 30, 2020): 2203–12. http://dx.doi.org/10.1002/jcc.26389.

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Kim, Taekyun, Jihoon Kim, and Tae Hee Lee. "Structure-Circuit Resistor Integrated Design Optimization of Piezoelectric Energy Harvester Considering Stress Constraints." Energies 16, no. 9 (April 27, 2023): 3766. http://dx.doi.org/10.3390/en16093766.

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A piezoelectric energy harvester (PEH) transduces mechanical energy into electrical energy, which can be utilized as an energy source for self-powered or low-power devices. Therefore, maximizing the power of a PEH is a crucial design objective. It is well known that structural designs are firstly conducted for controlling resonance characteristics, and then circuit designs are pursued through impedance matching for improving power. However, a PEH contains solid mechanics, electrostatics, and even a circuit-coupled multi-physics system. Therefore, this research aims to design a PEH considering a circuit-coupled multi-physics. As a design process, a conceptual design is developed by topology optimization, and a detailed design is developed sequentially by applying size optimization as a post-processing step to refine the conceptual design results for manufacturable design. In the two optimization processes, design optimizations of a structure coupled with circuit resistor are performed to maximize the power, where the electrical and mechanical interactions between PZT, substrate, and circuit resistor are simultaneously considered. Additionally, stress constraints are also added for structural safety to ensure operational life of PEH. As a result of the proposed design methodology, a manufacturable design of PEH having maximum power and operational life is obtained with power density of .

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Frost, T. H., B. Agnew, and A. Anderson. "Optimizations for Brayton-Joule Gas Turbine Cycles." Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy 206, no. 4 (November 1992): 283–88. http://dx.doi.org/10.1243/pime_proc_1992_206_045_02.

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Traditionally, the simple Brayton–Joule cycle has been optimized for maximum output and for minimum compressor work with inter-cooling and maximum turbine work with reheat. To these Woods et al. (1) have added optimization for peak efficiency of the simple cycle with internal irreversibilities. The results now presented include both maximum output and peak efficiency for both regenerative and intercool/reheat cycles with internal irreversibilities. Two special cases, for a regenerative cycle and for a non-regenerative cycle with both reheat and intercooling, are identified where the conditions for maximum output and peak efficiency coincide.

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Zhao, Lingying, Min Ye, and Xinxin Xu. "Intelligent optimization of EV comfort based on a cooperative braking system." Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering 235, no. 10-11 (March 19, 2021): 2904–16. http://dx.doi.org/10.1177/09544070211004461.

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To address the comfort of an electric vehicle, a coupling mechanism between mechanical friction braking and electric regenerative braking was studied. A cooperative braking system model was established, and comprehensive simulations and system optimizations were carried out. The performance of the cooperative braking system was analyzed. The distribution of the braking force was optimized by an intelligent method, and the distribution of a braking force logic diagram based on comfort was proposed. Using an intelligent algorithm, the braking force was distributed between the two braking systems and between the driving and driven axles. The experiment based on comfort was carried out. The results show that comfort after optimization is improved by 76.29% compared with that before optimization by comparing RMS value in the time domain. The reason is that the braking force distribution strategy based on the optimization takes into account the driver’s braking demand, the maximum braking torque of the motor, and the requirements of vehicle comfort, and makes full use of the braking torque of the motor. The error between simulation results and experimental results is 5.13%, which indicates that the braking force’s distribution strategy is feasible.

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An, Haichao, Shenyan Chen, Yanjie Liu, and Hai Huang. "Optimal design of the stacking sequences of a corrugated central cylinder in a satellite." Proceedings of the Institution of Mechanical Engineers, Part L: Journal of Materials: Design and Applications 233, no. 2 (September 29, 2016): 239–53. http://dx.doi.org/10.1177/1464420716672097.

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This Case Study is to describe an application of a two-level approximation method in optimally determining the stacking sequences of a practical corrugated central cylinder. Being housed in the center of a practical satellite, this cylinder can support many of the structural components and functional devices in the satellite. For the purpose of reducing its mass meanwhile maintaining good mechanical properties, the stacking sequences of this cylinder are to be optimally designed under given constraints in this paper. To address this problem, an optimization model was first established by minimizing the structural mass based on initial lay-ups. With the given lay-ups for multi-parts of this cylinder, the existence of each ply was to be determined in terms of discrete variables. Meanwhile, the ply thicknesses were also treated as continuous variables. The two-level approximation method combined with a genetic algorithm previously proposed by the authors was adopted as the optimization method. According to the practical engineering considerations, multiple optimizations were conducted by starting from different initial lay-ups to search more possible optimization designs. After optimization, it was found that compared with the empirical designs, the mass of the main cylinder could be significantly decreased by obtaining some reasonable stacking sequences.

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Messai, Hala, Salim Meziani, and Athmane Fouathia. "The prediction of the cyclic mechanical behavior of stainless steel 304L at room temperature." World Journal of Engineering 18, no. 5 (February 15, 2021): 675–83. http://dx.doi.org/10.1108/wje-07-2020-0259.

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Purpose The purpose of this paper is to highlight the performance of the Chaboche model in relation to the database identification, tests with imposed deformations were conducted at room temperature on 304L stainless steel specimens. Design/methodology/approach The first two tests were performed in tension-compression between ±0.005 and ±0.01; in the third test, each cycle is composed of the combination of a compression tensile cycle between ±0.01 followed by a torsion cycle between ±0.01723 (non-proportional path), and the last, uniaxial ratcheting test with a mean stress between 250 MPa and −150 MPa. Several identifications of a Chaboche-type model were then performed by considering databases composed of one or more of the cited tests. On the basis of these identifications, the simulations of a large number of ratchet tests in particular were carried out. Findings The results present the effect of the optimized parameters on the prediction of the behavior of materials which is reported in the graphs, Optimizations 1 and 2 of first and second tests and Optimization 4 of the third test giving a good prediction of the increasing/decreasing pre-deformation amplitude. Originality/value The quality of the model's predictions strongly depends on the richness of the database used for the identification of the parameters.

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Li, Xiaoyong, Xiao Chai, and Hong Liu. "Conceptual design optimization of a wide-body commercial aircraft using a competitiveness model." Proceedings of the Institution of Mechanical Engineers, Part G: Journal of Aerospace Engineering 234, no. 2 (July 23, 2019): 208–20. http://dx.doi.org/10.1177/0954410019862082.

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The conceptual design optimization of wide-body commercial aircraft is very challenging today. This paper deals with the conceptual design optimization problem of a next-cycle wide-body commercial aircraft, which has many similarities to the one being co-developed by China and Russia. The most difficult weaknesses are that the design requirements cannot be traded off during the conceptual design optimization process. To overcome this issue, a competitiveness model is built up for the wide-body commercial aircraft. The analytic hierarchy process is applied to formulate the competitiveness model, which is a multi-level evaluation model. The competiveness model includes three levels, i.e. target level, criteria level, and attributes level. The target level has an output, i.e. the competitiveness of the investigated aircraft, which serves as the single objective function in the conceptual design optimization problem. The criteria level includes four elements of economics, comfort, environmental impact, and adaptability. In addition, each criterion is further divided into more attributes, which are parameters obtained from the commercial aircraft conceptual design. By using the competitiveness model, the conceptual design optimization problem is converted into an unconstrained one that can be solved easily. Two optimizations with different judgment matrices for criteria level were performed. Compared with the baseline design candidate, the overall competitiveness of the optimal design for the optimization case 1 and case 2 increased by 9.28% and 11.51%, respectively, which benefits the designers and decision-makers.

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Dinner, P. J., and H. Yoshida. "ITER fuel cycle options and optimizations." Fusion Engineering and Design 16 (December 1991): 11–22. http://dx.doi.org/10.1016/0920-3796(91)90179-t.

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Leal, Pedro BC, Marcelo A. Savi, and Darren J. Hartl. "Aero-structural optimization of shape memory alloy-based wing morphing via a class/shape transformation approach." Proceedings of the Institution of Mechanical Engineers, Part G: Journal of Aerospace Engineering 232, no. 15 (July 12, 2017): 2745–59. http://dx.doi.org/10.1177/0954410017716193.

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Because of the continuous variability of the ambient environment, all aircraft would benefit from an in situ optimized wing. This paper proposes a method for preliminary design of feasible morphing wing configurations that provide benefits under disparate flight conditions but are also each structurally attainable via localized active shape change operations. The controlled reconfiguration is accomplished in a novel manner through the use of shape memory alloy embedded skin components. To address this coupled optimization problem, multiple sub-optimizations are required. In this work, the optimized cruise and landing airfoil configurations are determined in addition to the shape memory alloy actuator configuration required to morph between the two. Thus, three chained optimization problems are addressed via a common genetic algorithm. Each analysis-driven optimization considers the effects of both the deformable structure and the aerodynamic loading experienced by the wing. Aerodynamic considerations are addressed via a two-dimensional panel method and each airfoil shape is generated by the so-called class/shape transformation methodology. It is shown that structurally and aerodynamically feasible morphing of a modern high-performance sailplane wing produces a 22% decrease in weight and significantly increases stall angle of attack and lift at the same landing velocity when compared to a baseline design that employs traditional control surfaces.

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Song, Yi, Zhou Yi Wang, Ai Hong Ji, and Zhen Dong Dai. "Mechanical Performance Tests of Bamboo Beetles Otidognathus davidis fairs' Abdominal Shells." Applied Mechanics and Materials 461 (November 2013): 241–46. http://dx.doi.org/10.4028/www.scientific.net/amm.461.241.

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The biomaterials with excellent properties such as high strength-weights ratio and so on will inspire inspirations about bionic composite materials to satisfy the scalding hypercriticisms for aerial materials. The investigations of biomaterial mechanical performances are of great advantages in bionic designs and bionic manufactures. The mechanical performances of Bamboo BeetlesOtidognathus Davidis Fairs abdominal shells were tested with a nanoindenter in this paper. The experiments results demonstrated that the harnesses and modulus are different at different test areas. The mechanical performances resemble much at the same latitude but decrease along longitude from the forehead to the rearward, indicating that the mechanical performances of the abdominal shells distribute topologically. Whats more, the topological distributions of mechanical performances illustrate a kind of unlearned structure optimizations of insects which will provide edifications to designs of light and strong materials.

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Murphy, Ryan, Chikwesiri Imediegwu, Robert Hewson, and Matthew Santer. "Multiscale structural optimization with concurrent coupling between scales." Structural and Multidisciplinary Optimization 63, no. 4 (January 8, 2021): 1721–41. http://dx.doi.org/10.1007/s00158-020-02773-3.

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AbstractA robust three-dimensional multiscale structural optimization framework with concurrent coupling between scales is presented. Concurrent coupling ensures that only the microscale data required to evaluate the macroscale model during each iteration of optimization is collected and results in considerable computational savings. This represents the principal novelty of this framework and permits a previously intractable number of design variables to be used in the parametrization of the microscale geometry, which in turn enables accessibility to a greater range of extremal point properties during optimization. Additionally, the microscale data collected during optimization is stored in a reusable database, further reducing the computational expense of optimization. Application of this methodology enables structures with precise functionally graded mechanical properties over two scales to be derived, which satisfy one or multiple functional objectives. Two classical compliance minimization problems are solved within this paper and benchmarked against a Solid Isotropic Material with Penalization (SIMP)–based topology optimization. Only a small fraction of the microstructure database is required to derive the optimized multiscale solutions, which demonstrates a significant reduction in the computational expense of optimization in comparison to contemporary sequential frameworks. In addition, both cases demonstrate a significant reduction in the compliance functional in comparison to the equivalent SIMP-based optimizations.

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Cota, Luis Guillermo, and Pablo de la Mora. "On the structure of lithium peroxide, Li2O2." Acta Crystallographica Section B Structural Science 61, no. 2 (March 16, 2005): 133–36. http://dx.doi.org/10.1107/s0108768105003629.

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The two published lithium peroxide structures, both ascribed to the hexagonal P\bar 6 space group, were subjected to reinterpretation, and another more symmetric structure, now belonging to the P63/mmc space group, was found. Detailed density-functional quantum mechanical calculations and crystal structure optimizations were carried out on both structures and the energetic arguments obtained therewith helped to rule out one of them.

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Yin, Qiaozhi, Hong Nie, Xiaohui Wei, and Ming Zhang. "Aircraft electric anti-skid braking and combined direction control system using co-simulation and experimental methods." Proceedings of the Institution of Mechanical Engineers, Part G: Journal of Aerospace Engineering 234, no. 2 (May 28, 2019): 173–91. http://dx.doi.org/10.1177/0954410019852825.

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The work reported in this paper concentrates on the design and application of an electric ground control system combining the braking and steering mechanisms on a small unmanned aerial vehicle. A virtual prototype of a small unmanned aerial vehicle is built with a multibody dynamic software LMS Virtual.Lab Motion. An electric anti-skid braking system and a new combined direction control system considering the sensors models are established with MATLAB/Simulink. Optimizations are carried out using a global optimization command patternsearch first and then a local optimization method fminsearch for fine-tuning to design the dynamic allocation for the direction rectifying weight coefficients. Then a co-simulation method is introduced to study the ground maneuver performance so as to investigate the interaction of each subsystem via the interfaces between the two softwares. The anti-skid braking simulation verifies that the aircraft can stop smoothly and efficiently. The combined rectification control simulations in three different conditions verify the system stability and robustness. In addition, an anti-skid braking and a direction-control experiment are conducted. Results show that the experimental results fit well with the simulation and that the yaw angle can be corrected effectively under the designed control systems.

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Zhou, Zaiwei, Nuo Chen, Hongchuan Zhong, Wanli Zhang, Yue Zhang, Xiangyu Yin, and Bingwei He. "Textile-Based Mechanical Sensors: A Review." Materials 14, no. 20 (October 14, 2021): 6073. http://dx.doi.org/10.3390/ma14206073.

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Innovations related to textiles-based sensors have drawn great interest due to their outstanding merits of flexibility, comfort, low cost, and wearability. Textile-based sensors are often tied to certain parts of the human body to collect mechanical, physical, and chemical stimuli to identify and record human health and exercise. Until now, much research and review work has been carried out to summarize and promote the development of textile-based sensors. As a feature, we focus on textile-based mechanical sensors (TMSs), especially on their advantages and the way they achieve performance optimizations in this review. We first adopt a novel approach to introduce different kinds of TMSs by combining sensing mechanisms, textile structure, and novel fabricating strategies for implementing TMSs and focusing on critical performance criteria such as sensitivity, response range, response time, and stability. Next, we summarize their great advantages over other flexible sensors, and their potential applications in health monitoring, motion recognition, and human-machine interaction. Finally, we present the challenges and prospects to provide meaningful guidelines and directions for future research. The TMSs play an important role in promoting the development of the emerging Internet of Things, which can make health monitoring and everyday objects connect more smartly, conveniently, and comfortably efficiently in a wearable way in the coming years.

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Todoroki, Akira, Kentarou Suenaga, and Yoshinobu Shimamura. "Stacking sequence optimizations using modified global response surface in lamination parameters." Advanced Composite Materials 12, no. 1 (January 2003): 35–55. http://dx.doi.org/10.1163/156855103322320365.

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Padhy, Chinmaya, and Pariniti Singh. "Optimization of Machining Parameters using Taguchi Coupled Grey Relational Approach while Turning Inconel 625." Journal of Mechanical Engineering 18, no. 2 (April 15, 2021): 161–76. http://dx.doi.org/10.24191/jmeche.v18i2.15151.

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In manufacturing industries preparation of quality surfaces is very important. The surface roughness will influence the quality and effectiveness of the subsequent coatings for protection against corrosion, wear resistance etc. For achieving desired surface roughness, factors like cutting force (N) and material removal rate (mm3/sec) plays an important role towards final product optimization. This study helps to determine the contribution of each machining parameters [cutting speed (v), feed rate (f) and depth-of-cut (d)] and their interaction to investigate their optimum values during dry turning of Inconel 625 with the objective of enhancing the productivity (optimum production) by minimizing surface roughness (Ra), cutting forces (Fc), whereas maximizing material removal rate (MRR). This kind of multi response process variable (MRP) problems usually known as multi-objective optimizations (MOOs) are resolved with the help of Taguchi and Grey relation approach (T-GRA). As a result, the attained optimum cutting parameters are viz. cutting speed (60 m/min), feed rate (0.3 mm/rev), depth-of-cut (0.25 mm) lead to value of desired variables - cutting forces (340 N), surface roughness (0.998 μm) and material removal rate (0.786 mm3/min).

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Journal articles on the topic 'Mechanical optimizations'

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