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Experimental validation of optimisation strategies in hydroforming of T-shaped tubes

INTERNATIONAL JOURNAL OF MATERIAL FORMING 2008年第1-Sup期1卷 323-326页

作者： Di Lorenzo, R. Ingarao, G. Gagliardi, F. Filice, L. Univ Palermo Dipartimento Tecnol Meccan Prod & Ingn Gest I-90128 Palermo Italy Univ Calabria Dept Mech Engn I-87036 Arcavacata Di Rende CS Italy

For three dimensional tube hydroforming operations (i.e. T or Y shaped tubes) the calibration of both material feeding history and internal pressure path during the process is crucial and many approaches to such optimization were presented;the authors developed some procedures to optimize pressure paths and punch velocity histories with the application of an integrated method FEM - Gradient based optimization tools. In this paper, an experimental validation campaign of the utilized optimization strategies is presented with the aim to assess the effectiveness of the developed procedures. An optimization procedure (gradient based techniques) was applied on the process parameters leading to the determination of an optimal pressure path. Finally, a testing machine was set up to carry out hydroforming operations on T-shaped tubes. The developed equipment allows a computer assisted control of both the internal fluid pressure paths and the punches actions (material feeding paths). The experimental evidences validated the results obtained by the optimization strategies utilized to design the process parameters.

关键词： Tube hydroforming optimisation algorithms Experimental validation

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High voltage underground cable bonding optimisation to prevent cable termination faults in mixed high-voltage lines

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IET GENERATION TRANSMISSION & DISTRIBUTION 2020年第20期14卷 4331-4338页

作者： Akbal, Bahadir Konya Tech Univ Dept Elect & Elect Engn Selcuklu Konya Turkey

Cable termination fault (CTF) generally occurs due to increasing of electrical force (EF) and thermal effect (TE) in mixed line. EF increases due to sheath voltage (SV), and TE increases due to harmonic distortion (HD) on cable terminations (CTs). Also, SV and HD increase due to zero-sequence current (ZC). In the literature, different bonding methods are used to prevent CTF, but these methods are not sufficient to prevent CTF that is based on ZC. In this study, the modified sectional solid bonding (MSSB) is suggested to prevent CTF. The aims of MSSB method are to restrict EF and TE on CT. Thus, MSSB parameters are optimised to restrict SV and HD, but SV and HD on CT should be known for optimisation of MSSB parameters. Thus, SV and HD are forecasted by using adaptive neuro-fuzzy inference system (Anfis), artificial neural networks (ANNs) and hybrid ANN. Training and forecasting errors of hybrid ANN are less than Anfis and the other ANN methods. Thus, hybrid ANN methods are used as fitness function of optimisation algorithms in MSSB optimisation. When the optimised MSSB method is used for cable bonding, HD and SV on CT are restricted the determined limits to prevent CTF in long mixed line.

关键词： optimisation underground cables power engineering computing fuzzy neural nets power distribution faults power cables fuzzy reasoning harmonic distortion fault location MSSB parameters CT hybrid ANN methods optimisation algorithms MSSB optimisation optimised MSSB method CTF long mixed line high voltage underground cable bonding optimisation cable termination fault high-voltage lines thermal effect EF increases sheath voltage cable terminations HD increase zero-sequence current ZC different bonding methods modified sectional solid bonding

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Multi-adaptive neuro-fuzzy inference system modelling for prediction of band-notched behaviour of slotted-UWB antennas optimised using evolutionary algorithms

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IET MICROWAVES ANTENNAS & PROPAGATION 2020年第12期14卷 1396-1403页

作者： Sarkar, Debanjali Khan, Taimoor Talukdar, Fazal Ahmed Natl Inst Technol Silchar Dept Elect & Commun Engn Silchar Assam India

This study introduces modelling of multi-adaptive neuro-fuzzy inference system (MANFIS) for predicting the bandwidth and notch frequencies of slotted ultra-wideband (UWB) antennas. Rectangular-shaped printed monopole antennas embedded with U-shaped slots are designed to realise triple band-notch characteristics. A MANFIS model is then developed to predict five output parameters (two cut-off frequency points and three notched frequency points) considering 15 geometrical variables of the designed antennas as the inputs of MANFIS model. Extensive simulation has been performed using HFSS software to generate training and testing data patterns. Two optimisation algorithms, genetic algorithm (GA) and particle swarm optimisation (PSO), are implemented to optimally determine the appropriate values of the fuzzy inference system parameters. For GA-optimised MANFIS model, the percentage error is observed between 1 and 2%, whereas, in PSO-trained MANFIS model, it is observed <1%. The comparative analysis establishes that the PSO-trained MANFIS model precisely predicts the antenna performances. For validating the proposed modelling technique, an optimised configuration of the slotted UWB antenna prototype has been fabricated and characterised.

关键词： slot antennas fuzzy reasoning monopole antennas fuzzy neural nets ultra wideband antennas genetic algorithms particle swarm optimisation microstrip antennas telecommunication computing multifrequency antennas genetic algorithm data pattern testing HFSS software rectangular-shaped printed monopole antennas PSO-trained MANFIS model GA-optimised MANFIS model fuzzy inference system parameters particle swarm optimisation optimisation algorithms geometrical variables notched frequency points cut-off frequency points triple band-notch characteristics U-shaped slots ultrawideband antennas notch frequencies multiadaptive neuro-fuzzy inference system evolutionary algorithms slotted-UWB antennas band-notched behaviour neuro-fuzzy inference system modelling slotted UWB antenna prototype optimised configuration antenna performances

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Disturbance observer-based dynamic optimal setting control

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IET CONTROL THEORY AND APPLICATIONS 2018年第17期12卷 2423-2432页

作者： Yin, Liping Wang, Hong Yan, Xiaomo Zhang, Hongyan Nanjing Univ Informat Sci & Technol CICAEET Nanjing 210044 Jiangsu Peoples R China Pacific Northwest Natl Lab 902 Battelle Blvd Richland WA 99352 USA Univ Manchester Control Syst Ctr Manchester M13 9PL Lancs England

This study deals with optimal operational control problems using a novel approach where a performance index is optimised by controller design together with set-points reselection. Firstly, the operational indices are obtained by employing some optimisation algorithms. The controller is then designed for each closed loop to ensure that the controlled variables can track the set points in the ideal situation. Taking advantage of disturbance observers, the set-points are reselected dynamically to minimise the effect caused by unexpected noises or disturbances. In the proposed method, the controller structures or parameters are never changed no matter what kind of disturbance affects the whole system. Finally, two simulations are given to demonstrate the effectiveness and convenience of the proposed strategy.

关键词： optimisation control system synthesis closed loop systems performance index nonlinear control systems observers optimal control set points controlled variables optimisation algorithms operational indices set-points reselection controller design performance index optimal operational control problems disturbance observer-based dynamic optimal setting control parameters controller structures disturbances unexpected noises disturbance observers

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Path planning in construction sites: performance evaluation of the Dijkstra, A*, and GA search algorithms

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ADVANCED ENGINEERING INFORMATICS 2002年第4期16卷 291-303页

作者： Soltani, AR Tawfik, H Goulermas, JY Fernando, T Univ Salford Ctr Virtual Environm Inst Informat Syst Adv Virtual Prototyping Grp Salford M5 4WT Lancs England

This paper presents the application of path planning in construction sites according to multiple objectives. It quantitatively evaluates the performance of three optimisation algorithms namely: Dijkstra, A*, and Genetic algorithms that are used to find multi-criteria paths in construction sites based on transportation and safety-related cost. During a construction project, site planners need to select paths for site operatives and vehicles, which are characterised by short distance, low risks and high visibility. These path evaluation criteria are combined using a multi-objective approach. The criteria can be optimised to present site planners with the shortest path, the safest path, the most visible path or a path that reflects a combination of short distance, low risk and high visibility. The accuracy of the path solutions and the time complexities of the optimisation algorithms are compared and critically analysed. (C) 2003 Elsevier Ltd. All rights reserved.

关键词： construction site path finding multi-criteria optimisation algorithms

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Ergonomic Level Improving of Armoured Fighting Vehicle Crew

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DEFENCE SCIENCE JOURNAL 2018年第1期68卷 33-45页

作者： Ramamurthy, N. V. Vinayagam, B. K. Roopchand, J. DRDO Combat Vehicles Res & Dev Estab Min Def Madras 600054 Tamil Nadu India SRM Univ Dept Mechatron Kattankulathur 603203 India

The armoured fighting vehicle (AFV) -occupant composite system is modelled as a lumped parameter system, in this paper, wherein the 4 degrees of freedom (dof) biodynamic occupant model is integrated with 10 dof inplane AFV model including the crew seat, thus leading to the 14 dof vehicle-occupant composite model and the governing equations of motion are obtained. The composite model is subjected to idealised road input simulating the ground reaction forces. Natural frequencies and the frequency domain vibration responses of various masses of model are obtained. The natural frequency of chassis thus obtained is compared with the result established by an earlier research work, to validate the model. The study is focused on crew seat location. A 2 dof occupant-seat suspension model is formulated and validated through case study. The optimised values of seat suspension parameters for ride comfort are obtained using the said model, through two methods of Invariant points theory and genetic algorithm toolbox of Matlab 2014 a software. Acceleration responses of body for the current and optimised parameter values obtained illustrate that comfort of crew is improved with optimised values through minimization in the acceleration responses.

关键词： Vibration responses Vehicle-occupant system Seat suspension system Mathematical model optimisation algorithms GA

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VARIANT DESIGNING IN THE PRELIMINARY SMALL SHIP DESIGN PROCESS

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POLISH MARITIME RESEARCH 2017年第2期24卷 77-82页

作者： Karczewski, Artur Kozak, Janusz Gdansk Univ Technol Fac Ocean Engn & Ship Technol Narutowicza 11-12 PL-80233 Gdansk Poland

Ship designing is a complex process, as the ship itself is a complex, technical multi-level object which operates in the air/water boundary environment and is exposed to the action of many different external and internal factors resulting from the adopted technical solutions, type of operation, and environmental conditions. A traditional ship design process consists of a series of subsequent multistage iterations, which gradually increase the design identification level. The paper presents problems related to the design of a small untypical vessel with the aid of variant methodology making use of optimisation algorithms. The computer-aided design methodology has been developed which does not need permanent reference to already built real ships and empirical-statistical relations. Possibilities were indicated for integrating together early design stages, and parallel designing of hull shape and parameters.

关键词： ship design design methodology optimisation algorithms

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Methodology of aircraft structural design optimisation

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INTERNATIONAL JOURNAL OF COMPUTER APPLICATIONS IN TECHNOLOGY 2022年第3-4期70卷 145-154页

作者： Yang, Nihong Univ West England Sch Engn Bristol England

Aircraft structural design normally aims to achieve the lightest weight for fuel saving in operations while meeting aircraft performance requirements. Various optimisation methods and approaches are used in structural design optimisation. This paper reviews the aircraft structural optimisation process and methods currently applied in aircraft structural design, including structural analysis and optimisation process, FEA modelling techniques and optimisation algorithms. It is seen that a two-step global local approach is extensively applied in aircraft structural optimisation. Submodelling technique is often used in the global local optimisation, whereas superelement technique can provide accurate solutions. Gradient based optimisation algorithms are suitable for optimisation problems with continuous variables such as size and distance of metallic aircraft structures, whilst genetic algorithms and particle swarm optimisation algorithms are often used for optimisation problems with discrete variables such as laminate composite thickness and stacking sequence. Selection of analysis techniques and optimisation algorithms depends on structure scale for optimisation, computing resources available, and nature of the specific optimisation problem.

关键词： aircraft structures design optimisation FEA modelling techniques laminated composites numerical modelling optimisation algorithms

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Modelling and mathematical results arising from ferromagnetic problems

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Science China Mathematics 2012年第5期55卷 1053-1067页

作者： DESCLOUX Jean FLUECK Michel RAPPAZ Jacques Department of Mathematics Ecole Polytechnique Fdrale de Lausanne (EPFL)Lausanne 1015Switzerland

Abstract In this article, we investigate the equations of magnetostaties for a configuration where a ferromagnetic material occupies a bounded domain and is surrounded by vacuum. Furthermore, the ferromagnetic law takes the form B=μ0μr（｜H｜）Hi i.e., the magnetizing field H and the magnetic induction B are collinear, but the relative permeability μr is allowed to depend on the modulus of H. We prove the well-posedness of the magnetostatic problem under suitable convexity assumptions, and the convergence of several iterative methods, both for the original problem set in the Beppo-Levi space W1（R3）, and for a finite-dimensional approximation. The theoretical results are illustrated by numerical examples, which capture the known physical phenomena.

关键词： ferromagnetism nonlinear elliptic problems finite element methods optimisation algorithms

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Learning regular expressions to template-based FAQ retrieval systems

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KNOWLEDGE-BASED SYSTEMS 2013年 53卷 108-128页

作者： Moreo, A. Eisman, E. M. Castro, J. L. Zurita, J. M. Univ Granada Dep Comp Sci & Artificial Intelligence E-18071 Granada Spain

Template-based approaches have proven to be one of the most efficient and robustest ways of addressing Question Answering problems. Templates embody the expert's knowledge on the domain and his/her ability to understand and answer questions, but designing these templates may become a complex task since it is usually carried out manually. Although these methods are not automatic, companies may prefer to undertake this solution in order to offer a better service. In this article, we propose a semiautomatic method to reduce the problem of creating templates to that of validate, and possibly modify, a list of proposed templates. In this way, a better trade-off between reliability the system is still monitored by an expert and cost is achieved. In addition, updating templates after domain changes becomes easier, human mistakes are reduced, and portability is increased. Our proposal is based on inferring regular expressions that induce the language conveyed by a set of previously collected query reformulations. The main contribution of this work consists of the definition of a suitable optimisation measure that effectively reflects some important aspects of the problem and the theoretical soundness that supports it. (C) 2013 Elsevier B.V. All rights reserved.

关键词： Learning regular expressions Template-based QA FAQ retrieval optimisation algorithms Cost reduction

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