Papers by Keyword: Hybrid

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Authors: Jin Ling Guo, Shi Wei Yu
Abstract: This study primarily focuses on solving a practical OVRP by applying a novel hybrid adaptive Genetic Algorithm and Tabu Search (GA-TS). The GA-TS combines the GA's parallel computing and global optimization with TS's Tabu search skill and fast local search. In the GA-TS Algorithm, individuals of population do TS local search with a certain degree of probability using natural number coding. It not only ensures global optimization, but also improves the speed of computing. The Algorithm is applied to optimize the mines material transport vehicle routing of China Zhengzhou Coal Mine and power Supply Co., Ltd. Through the applications, the optimal economical transport routing has been set up and economic costs have been greatly reduced.
Authors: Xiao Mei Yang
Abstract: In this paper, an eight-node solid hybrid-stabilized element for general piezoelectric laminate plate analysis is formulated based on the electromechanical Hellinger-Reissner functional. The independent field variables in the functional include the displacement, electric potential, stress and electric displacement. The non-constant electromechanical stress modes are contravariant in nature and chosen to be orthogonal with respect to the constant ones. The othogonality and the practice put forward in the admissible matrix formulation allow the electromechanical flexibility matrices to be block diagonal. As a result, the computational cost for inverting the electromechanical flexibility matrices can be greatly reduced. Numerical examples indicate that the proposed hybrid piezoelectric element is more accurate than their conventional counterpart.
Authors: Yu Yu Zhou, Yun Qing Rao, Chao Yong Zhang, Guo Jun Zhang
Abstract: In this paper we address a rectangular packing problem (RPP), which is one of the most difficult NP-complete problems. First, greedy biggest space sequencing (GBSS) is presented as a new placement strategy, which is very essential to RPP. Then, borrowing from the respective advantages of the two algorithms, genetic algorithm (GA) and simulated annealing (SA), a hybrid optimization policy is developed. The hybrid GASA is subjected to a test using a set of benchmarks. Compared to other approaches from the literature the hybrid optimization strategy performs better.
Authors: Norelislam Elhami, Rachid Ellaia, Mhamed Itmi
Abstract: This paper presents a new methodology for the Reliability Based Particle Swarm Optimization with Simulated Annealing. The reliability analysis procedure couple traditional and modified first and second order reliability methods, in rectangular plates modelled by an Assumed Modes approach. Both reliability methods are applicable to the implicit limit state functions through numerical models, like those based on the Assumed Mode Method. For traditional reliability approaches, the algorithms FORM and SORM use a Newton-Raphson procedure for estimate design point. In modified approaches, the algorithms are based on heuristic optimization methods such as Particle Swarm Optimization and Simulated Annealing Optimization. Numerical applications in static, dynamic and stability problems are used to illustrate the applicability and effectiveness of proposed methodology. These examples consist in a rectangular plates subjected to in-plane external loads, material and geometrical parameters which are considered as random variables. The results show that the predicted reliability levels are accurate to evaluate simultaneously various implicit limit state functions with respect to static, dynamic and stability criterions.
Authors: Qing Guo Zhang, Li Min Shi, Cheng Li Zhang, Shuang Long Wang
Abstract: A new fluorescent Carbon Quantum Dots-Ionic Liquid (CQDIL) hybrid was synthesized by simple method. This CQDIL exhibited extraordinary stability and enhanced photoluminescence .
Authors: Vemu Vara Prasad, Javisseti Nageswara Rao
Abstract: Among various composites available for use, carbon fiber reinforced composite is unique in its Nature. Carbon fiber is an extremely strong thin fiber made by pyrolyzing synthetic fibers, such as rayon, until charred. High Strength Composites are made from this fiber by using appropriate matrix material mostly Epoxy resins are used. High Strength, stiffness, light weight and high thermal conductivity are the main advantages over the other composites. Making products with one single composite sheet is not possible always. Some of the intricate or complex shape making is required for joining of two composite sheet. The composites joining can be done in three ways mainly Adhesive, Riveting and Hybrid. Based on the Review among all these joints adhesive joining gives better economic solution in joining. Experimental results point to significant influence of fibre on mechanical properties of sample. The tensile test of the acoustic signal emission (AE) to identify the current state of material integrity in real time. Acoustic system signal correlated to damage events. The carbon fiber composite characteristic failure mechanisms are initiated on the microscale and result in a spontaneous release of elastic energy in terms of mechanical stress waves, the so-called acoustic emissions.
Authors: G.İ. Öztürk, H.T. Vakos, W. Voelter, A. Taralp
Authors: John Liu
Abstract: Alcoa has made a fundamental shift in its aerospace R&D program, broadening its scientific and engineering portfolio by creating an integrated, strategic, long-term initiative. The ultimate goal is to help re-define the future performance, cost and value of the metallic and hybrid aerostructures that the company feels will be required to meet the mission requirements of tomorrow’s aircraft. Having intensely studied various structural options, Alcoa believes Hybrid Structural Assembly optimized with a combination of Advanced Aluminum and Hybrid Components offer the best opportunities to maximize structural performance. Not only do the new alloys, notably 3rd Generation Al-Li alloys and high strength and high toughness 7xxx alloys provide structural performance enhancements, they also offer dramatic improvements in corrosion resistance. In this paper, several advanced alloys and structural concepts targeted for next generation wing and fuselage applications and large scale test article results supporting Alcoa’s optimism for Advanced Metallic and Hybrid Structures are reviewed.
Authors: Mihaița Adrian Matara, Ioana Csáki, Mariana Lucaci, Magdalena Lungu, Gabriela Popescu, Gheorghe Iacob
Abstract: The researches have been focused on composite materials area, especially hybrid metal matrix composites. A hybrid composite has two or more reinforcing elements and improved properties according to the reinforcing elements used.This paper aims to discuss the Al/Al2O3+Grp behavior at different pressing forces. The composite was processed by a powder metallurgy route. Alumina used as reinforcing material provides a high strength and hardness and graphite provides lubricating properties. The results show that the compressed un-granulated powder has a higher tendency to fracture than the granulated powder. The compressed powder density was almost constant after a pressing force of 600 MPa.
Authors: Yu Yu Zhou, Yun Qing Rao, Chao Yong Zhang, Guo Jun Zhang
Abstract: We address a two dimensional bin packing problem in this paper. Firstly, we adopt and improve bottom left placement method, which is presented as bottom left corner-occupying (BLCO). Secondly, borrowing from the respective advantages of the two algorithms, a hybrid of genetic algorithm (GA) and tabu search (TS), is developed to solve the problem. Thirdly, using a new neighborhood structure combined with the appropriate move evaluation strategy, we propose TS to re-intensify search from the promising solutions. The hybrid GATS is tested on a set of instances taken from the literature and the computation results validate the quality of the solutions.
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