scholarly journals Parameter Study on Weight Minimization of Network Arch Bridges

2017 ◽  
Author(s):  
Rimantas Belevicius ◽  
Algirdas Juozapaitis ◽  
Dainius Rusakevičius
Keyword(s):  
Optimization Problem ◽  
Minimum Weight ◽  
Optimization Technique ◽  
Mixed Integer ◽  
Design Parameters ◽  
Parameter Study ◽  
Large Set ◽  
Topological Parameters ◽  
Arch Bridges ◽  
Arch Shape

The article concerns optimization of network arch bridges. This is challenging optimization problem involving even for conventional scheme of network arch bridge the identification of some topological parameters as well as shape configurations and all sizing parameters of structural members, seeking the minimum weight. Optimal bridge scheme is sought tuning a large set of design parameters of diverse character: the type of hanger arrangement, the number of hangers, their inclination angles and placement distances, the arch shape and rise, etc. Mathematically, the optimization of the bridge scheme is a mixed-integer constrained global optimization problem solved employing stochastic evolutionary algorithm. Plane heavy/moderate/and light-deck bridges of 18, 30, 42 and 54 m spans were optimized using proposed optimization technique. The decisive design parameters and their promising ranges were revealed. Also, the influence of some simplifications is shown: changing the arch shape from elliptical to circular, placing the hangers at equal distances, etc.

Parameter study and optimization design of a hat oblique tunnel portal

2021 ◽  
pp. 095440972110140
Author(s):  
Zijian Guo ◽  
Tanghong Liu ◽  
Wenhui Li ◽  
Yutao Xia
Keyword(s):  
High Speed ◽  
Optimization Design ◽  
Pareto Front ◽  
Optimization Problem ◽  
Optimization Method ◽  
Design Parameters ◽  
Parameter Study ◽  
Buffer Structure ◽  
Tunnel Entrance ◽  
The Ideal

The present work focuses on the aerodynamic problems resulting from a high-speed train (HST) passing through a tunnel. Numerical simulations were employed to obtain the numerical results, and they were verified by a moving-model test. Two responses, [Formula: see text] (coefficient of the peak-to-peak pressure of a single fluctuation) and[Formula: see text] (pressure value of micro-pressure wave), were studied with regard to the three building parameters of the portal-hat buffer structure of the tunnel entrance and exit. The MOPSO (multi-objective particle swarm optimization) method was employed to solve the optimization problem in order to find the minimum [Formula: see text] and[Formula: see text]. Results showed that the effects of the three design parameters on [Formula: see text] were not monotonous, and the influences of[Formula: see text] (the oblique angle of the portal) and [Formula: see text] (the height of the hat structure) were more significant than that of[Formula: see text] (the angle between the vertical line of the portal and the hat). Monotonically decreasing responses were found in [Formula: see text] for [Formula: see text] and[Formula: see text]. The Pareto front of [Formula: see text] and[Formula: see text]was obtained. The ideal single-objective optimums for each response located at the ends of the Pareto front had values of 1.0560 for [Formula: see text] and 101.8 Pa for[Formula: see text].

Sensitivity Analysis for the Operating Efficiency of an Axial Piston Pump

2015 ◽  
Author(s):  
Noah D. Manring ◽  
Viral S. Mehta ◽  
Jeff L. Kuehn ◽  
Bryan E. Nelson
Keyword(s):  
Power Efficiency ◽  
Design Parameters ◽  
Operating Efficiency ◽  
Parameter Study ◽  
Total Efficiency ◽  
Pump Efficiency ◽  
Large Set ◽  
Algebraic Equations ◽  
Pump Design ◽  
Axial Piston

Axial piston pumps of swash-plate type are extensively used in off-highway machines to convert rotating mechanical power into hydraulic power. Efficiency of such pumps is of considerable importance to hydraulic design engineers. Many researchers have tried to create mathematical models for describing pump efficiency. These models are typically a system of nonlinear algebraic equations dependent upon a total of four variables (pressure, speed, temperature, displacement) and a set of experimentally determined coefficients. Since these models are not of the a-priori type, they are not of much value to a design engineer who is trying to design an efficient pump. Others have tried to use physics based models and numerical programs to accurately predict the influence of component design on efficiency. Such programs are considerably slow to run and of not much use to a design engineer who needs to make quick decisions. Hence the objective of this paper is to understand the sensitivity of various design parameters on the total efficiency of the pump by conducting a dimensionless parameter study of a large set of pump design parameters. Using this method it will be shown that a small group of design parameters have the highest influence on the efficiency of these pumps.

scholarly journals Numerical optimization of the piezoelectric generators

2020 ◽  
Vol 10 (01n02) ◽  
pp. 2060016
Author(s):  
V. A. Chebanenko ◽  
I. V. Zhilyaev ◽  
A. N. Soloviev ◽  
A. V. Cherpakov ◽  
I. A. Parinov
Keyword(s):  
Finite Element Method ◽  
Numerical Optimization ◽  
Output Voltage ◽  
Optimization Problem ◽  
Optimization Technique ◽  
Maximum Output Power ◽  
Operating Conditions ◽  
Design Parameters ◽  
Maximum Output ◽  
The Finite Element Method

This paper presents the application of the Pareto-based multicriteria optimization technique to problems of increasing the efficiency of piezoelectric generators (PEGs). The optimization problem was solved for two types of generators: cantilever and stack. For the cantilever generator, the task was to optimize the design in such a way as to obtain the maximum output power for a given mechanical excitation. The optimization process was divided into several stages, which significantly reduced the amount of calculations. The task of optimizing the stack type for a given form of mechanical loading consisted in finding the geometric parameters of the generator at which the output voltage and power would be maximum. In the result of solving both problems, sets of geometric design parameters of PEGs were obtained, on the basis of which efficient transducers can be developed for specific operating conditions. It turned out that this technique is more suitable for optimizing the design of cantilever generators than for stack ones in given constraints. The solution of both problems was realized using the finite element method.

Layout Method of a FPSO (Floating, Production, Storage, and Off-Loading Unit) Using the Optimization Technique

2014 ◽  
Author(s):  
Namkug Ku ◽  
Se-Yong Jeong ◽  
Myung-Il Roh ◽  
Hyun-Kyoung Shin ◽  
Sol Ha ◽  
...  
Keyword(s):  
Genetic Algorithm ◽  
Linear Programming ◽  
Mixed Integer Linear Programming ◽  
Optimization Problem ◽  
Optimization Technique ◽  
Salt Content ◽  
Layout Design ◽  
Mixed Integer ◽  
Optimal Layout ◽  
Special Environment

In the case of a floating offshore plant such as FPSO (Floating, Production, Storage, and Off-loading unit), many equipment should be installed in the limited space, as compared with an onshore plant. At this time, special conditions, such as the movement due to external force by wind and wave, salt content, and so on, should be also considered because the floating offshore plant should be operated in the special environment of ocean. The requirement for an optimal layout method of the plant has been raised due to much considerations for layout design. Thus, a layout method of the floating offshore plant was proposed in this study. For this, an optimization problem for layout was mathematically formulated, and then an optimization algorithm was implemented based on the genetic algorithm or mixed integer linear programming in order to solve it. To evaluate the applicability of the proposed method, it was applied to an example of FPSO and LNG FPSO topsides. As a result, it was shown that the proposed method can be applied to layout design of the floating offshore plant.

Reliability optimization in stochastic domain via genetic algorithm

2014 ◽  
Vol 31 (6) ◽  
pp. 698-717 ◽  
Author(s):  
Laxminarayan Sahoo ◽  
Asoke Kumar Bhunia ◽  
Dilip Roy
Keyword(s):  
Genetic Algorithm ◽  
Optimization Problem ◽  
Optimization Problems ◽  
Optimization Technique ◽  
Mixed Integer ◽  
Reliability Optimization ◽  
Programming Technique ◽  
Content Type ◽  
Real Coded Genetic Algorithm ◽  
Interval Valued

Purpose – The purpose of this paper is to formulate the reliability optimization problem in stochastic and interval domain and also to solve the same under different stochastic set up. Design/methodology/approach – Stochastic programming technique has been used to convert the chance constraints into deterministic form and the corresponding problem is transformed to mixed-integer constrained optimization problem with interval objective. Then the reduced problem has been converted to unconstrained optimization problem with interval objective by Big-M penalty technique. The resulting problem has been solved by advanced real coded genetic algorithm with interval fitness, tournament selection, intermediate crossover and one-neighbourhood mutation. Findings – A new optimization technique has been developed in stochastic domain and the concept of interval valued parameters has been integrated with the stochastic setup so as to increase the applicability of the resultant solution to the interval valued nonlinear optimization problems. Practical implications – The concept of probability distribution with interval valued parameters has been introduced. This concept will motivate the researchers to carry out the research in this new direction. Originality/value – The application of genetic algorithm is extended to solve the reliability optimization problem in stochastic and interval domain.

scholarly journals Beam Allocation and Power Optimization for Energy-Efficiency in Multiuser mmWave Massive MIMO System

Sensors ◽  
2021 ◽  
Vol 21 (7) ◽  
pp. 2550
Author(s):  
Saidiwaerdi Maimaiti ◽  
Gang Chuai ◽  
Weidong Gao ◽  
Jinxi Zhang
Keyword(s):  
Energy Efficiency ◽  
Power Consumption ◽  
Optimization Problem ◽  
Power Optimization ◽  
Mimo System ◽  
Optimization Technique ◽  
Mixed Integer ◽  
Optimization Scheme ◽  
Quadratic Transformation ◽  
Convex Problem

This paper studies beam allocation and power optimization scheme to decrease the hardware cost and downlink power consumption of a multiuser millimeter wave (mmWave) massive multiple-input multiple-output (MIMO) system. Our target is to improve energy efficiency (EE) and decrease power consumption without obvious system performance loss. To this end, we propose a beam allocation and power optimization scheme. First, the problem of beam allocation and power optimization is formulated as a multivariate mixed-integer non-linear programming problem. Second, due to the non-convexity of this problem, we decompose it into two sub-problems which are beam allocation and power optimization. Finally, the beam allocation problem is solved by using a convex optimization technique. We solve the power optimization problem in two steps. First, the non-convex problem is converted into a convex problem by using a quadratic transformation scheme. The second step implements Lagrange dual and sub-gradient methods to solve the optimization problem. Performance analysis and simulation results show that the proposed algorithm performs almost identical to the exhaustive search (ES) method, while the greedy beam allocation and suboptimal beam allocation methods are far from the ES. Furthermore, experiment results demonstrated that our proposed algorithm outperforms the compared the greedy beam allocation method and the suboptimal beam allocation scheme in terms of average service ratio.

A new algorithm for finding CRM-model coefficients

2019 ◽  
Vol 5 (3) ◽  
pp. 164-185 ◽  
Author(s):  
Alexander D. Bekman ◽  
Sergey V. Stepanov ◽  
Alexander A. Ruchkin ◽  
Dmitry V. Zelenin
Keyword(s):  
Approximate Solution ◽  
Optimization Problem ◽  
Optimal Solution ◽  
Complex Form ◽  
Approximate Solutions ◽  
The Other ◽  
Programming Algorithm ◽  
Stochastic Algorithms ◽  
Large Set ◽  
Flow Rates

The quantitative evaluation of producer and injector well interference based on well operation data (profiles of flow rates/injectivities and bottomhole/reservoir pressures) with the help of CRM (Capacitance-Resistive Models) is an optimization problem with large set of variables and constraints. The analytical solution cannot be found because of the complex form of the objective function for this problem. Attempts to find the solution with stochastic algorithms take unacceptable time and the result may be far from the optimal solution. Besides, the use of universal (commercial) optimizers hides the details of step by step solution from the user, for example&nbsp;— the ambiguity of the solution as the result of data inaccuracy.<br> The present article concerns two variants of CRM problem. The authors present a new algorithm of solving the problems with the help of “General Quadratic Programming Algorithm”. The main advantage of the new algorithm is the greater performance in comparison with the other known algorithms. Its other advantage is the possibility of an ambiguity analysis. This article studies the conditions which guarantee that the first variant of problem has a unique solution, which can be found with the presented algorithm. Another algorithm for finding the approximate solution for the second variant of the problem is also considered. The method of visualization of approximate solutions set is presented. The results of experiments comparing the new algorithm with some previously known are given.

scholarly journals Social spider optimization algorithm for tuning parameters in PD-like Interval Type-2 Fuzzy Logic Controller applied to a parallel robot

2021 ◽  
Vol 54 (3-4) ◽  
pp. 303-323
Author(s):  
Amjad J Humaidi ◽  
Huda T Najem ◽  
Ayad Q Al-Dujaili ◽  
Daniel A Pereira ◽  
Ibraheem Kasim Ibraheem ◽  
...  
Keyword(s):  
Fuzzy Logic ◽  
Trajectory Tracking ◽  
Fuzzy Logic Controller ◽  
Optimization Technique ◽  
Parallel Robot ◽  
Design Parameters ◽  
Social Spider ◽  
Social Spider Optimization ◽  
Interval Type

This paper presents control design based on an Interval Type-2 Fuzzy Logic (IT2FL) for the trajectory tracking of 3-RRR (3-Revolute-Revolute-Revolute) planar parallel robot. The design of Type-1 Fuzzy Logic Controller (T1FLC) is also considered for the purpose of comparison with the IT2FLC in terms of robustness and trajectory tracking characteristics. The scaling factors in the output and input of T1FL and IT2FL controllers play a vital role in improving the performance of the closed-loop system. However, using trial-and-error procedure for tuning these design parameters is exhaustive and hence an optimization technique is applied to achieve their optimal values and to reach an improved performance. In this study, Social Spider Optimization (SSO) algorithm is proposed as a useful tool to tune the parameters of proportional-derivative (PD) versions of both IT2FLC and T1FLC. Two scenarios, based on two square desired trajectories (with and without disturbance), have been tested to evaluate the tracking performance and robustness characteristics of proposed controllers. The effectiveness of controllers have been verified via numerical simulations based on MATLAB/SIMULINK programming software, which showed the superior of IT2FLC in terms of robustness and tracking errors.

scholarly journals Joint optimization of computing ratio and access points’ density for mixed mobile edge/cloud computing

2021 ◽  
Vol 2021 (1) ◽  
Author(s):  
Tianqi Jing ◽  
Shiwen He ◽  
Fei Yu ◽  
Yongming Huang ◽  
Luxi Yang ◽  
...  
Keyword(s):  
Cloud Computing ◽  
Coverage Probability ◽  
Optimization Problem ◽  
Mobile Cloud Computing ◽  
Low Complexity ◽  
Mixed Integer ◽  
Joint Optimization ◽  
Mobile Cloud ◽  
Convex Problem

AbstractCooperation between the mobile edge computing (MEC) and the mobile cloud computing (MCC) in offloading computing could improve quality of service (QoS) of user equipments (UEs) with computation-intensive tasks. In this paper, in order to minimize the expect charge, we focus on the problem of how to offload the computation-intensive task from the resource-scarce UE to access point’s (AP) and the cloud, and the density allocation of APs’ at mobile edge. We consider three offloading computing modes and focus on the coverage probability of each mode and corresponding ergodic rates. The resulting optimization problem is a mixed-integer and non-convex problem in the objective function and constraints. We propose a low-complexity suboptimal algorithm called Iteration of Convex Optimization and Nonlinear Programming (ICONP) to solve it. Numerical results verify the better performance of our proposed algorithm. Optimal computing ratios and APs’ density allocation contribute to the charge saving.

Workspace, dexterity and dimensional optimization of microhexapod

2015 ◽  
Vol 35 (4) ◽  
pp. 341-347 ◽  
Author(s):  
E. Rouhani ◽  
M. J. Nategh
Keyword(s):  
Degrees Of Freedom ◽  
Optimization Problem ◽  
Screw Theory ◽  
Design Parameters ◽  
Dimensional Synthesis ◽  
Content Type ◽  
Workspace Analysis ◽  
The Difference ◽  
Flexure Joints ◽  
6 Degrees Of Freedom

Purpose – The purpose of this paper is to study the workspace and dexterity of a microhexapod which is a 6-degrees of freedom (DOF) parallel compliant manipulator, and also to investigate its dimensional synthesis to maximize the workspace and the global dexterity index at the same time. Microassembly is so essential in the current industry for manufacturing complicated structures. Most of the micromanipulators suffer from their restricted workspace because of using flexure joints compared to the conventional ones. In addition, the controllability of micromanipulators inside the whole workspace is very vital. Thus, it is very important to select the design parameters in a way that not only maximize the workspace but also its global dexterity index. Design/methodology/approach – Microassembly is so essential in the current industry for manufacturing complicated structures. Most of the micromanipulators suffer from their restricted workspace because of using flexure joints compared to the conventional ones. In addition, the controllability of micromanipulators inside the whole workspace is very vital. Thus, it is very important to select the design parameters in a way that not only maximize the workspace but also its global dexterity index. Findings – It has been shown that the proposed procedure for the workspace calculation can considerably speed the required calculations. The optimization results show that a converged-diverged configuration of pods and an increase in the difference between the moving and the stationary platforms’ radii cause the global dexterity index to increase and the workspace to decrease. Originality/value – The proposed algorithm for the workspace analysis is very important, especially when it is an objective function of an optimization problem based on the search method. In addition, using screw theory can simply construct the homogeneous Jacobian matrix. The proposed methodology can be used for any other micromanipulator.

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