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Light-Weight Design Method for Force-Performance-Structure of Complex Structural Part Based Co-operative Optimization

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Chinese Journal of mechanical engineering 2018年第2期31卷 115-123页

作者： Ya-Li Ma Jian-Rong Tan De-Lun Wang Zi-Zhe Liu School of mechanical engineering Dalian University of Technology School of mechanical engineering Zhejiang University

A light?weight design method of integrated structural topology and size co?optimization for the force?performance?structure of complex structural parts is presented in this paper. Firstly, the supporting function of a complex structural part is built to map the force transmission, where the force exerted areas and constraints are considered as connecting structure and the structural configuration, to determine the part performance as well as the force routines. Then the connecting structure design model, aiming to optimize the static and dynamic performances on connection configuration, is developed, and the optimum design of the characteristic parameters is carried out by means of the collaborative optimization method, namely, the integrated structural topology optimization and size optimization. In this design model, the objective is to maximize the connecting stiffness. Based on the relationship between the force and the structural configuration of a part, the optimal force transmission routine that can meet the performance requirements is obtained using the structural topology optimization technology. Accordingly, the light?weight design of conceptual configuration for complex parts under multi?objective and multi?condition can be realized. Finally, based on the proposed collaborative optimization design method, the optimal performance and optimal structure of the complex parts with light weight are realized, and the reasonable structural unit configuration and size charac?teristic parameters are obtained. A bed structure of gantry?type machining center is designed by using the proposed light?weight structure design method in this paper, as an illustrative example. The bed after the design optimization is lighter 8% than original one, and the rail deformation is reduced by 5%. Moreover, the lightweight design of the bed is achieved with enhanced performance to show the effectiveness of the proposed method.

关键词： Light?weight design Part structure Topology optimization Size optimization Force Performance

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Continuum damage mechanics for sintered powder metals

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Science China(Physics,Mechanics & Astronomy) 2015年第1期58卷 95-106页

作者： YUAN Huang MA SongYun ZHANG Long Beijing Institute of Technology School of Mechanical Engineering University of Wuppertal Department of Mechanical Engineering

Sintered metals are characterized by the high porosity(8%)and voids/micro-cracks in *** behavior of the materials is coupled with micro-crack propagation and coalescence of open *** the present work the damage evolution of the sintered iron under multi-axial monotonic loading conditions was investigated experimentally and *** tests indicated that damage of the sintered iron initiated already at a stress level much lower than the macroscopic yield *** damage process can be divided into the stress-dominated elastic damage and the plastic damage described by the plastic *** on the uniaxial tensile tests an elastic-plastic continuum damage model was developed which predicts both elastic damage and plastic damage in the sintered iron under general multi-axial monotonic loading *** predictions agree with experiments with different multi-axial loading paths.A phenomenological continuum damage model for the sintered metal is developed based on the experimental observations to predict the inelastic behavior and damage process to failure under multi-axial loading *** proposed damage model is experimentally verified under different loading conditions.

关键词： sintered metal porous material damage evolution multi-axial damage continuum damage model

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An Intelligent Harmonic Synthesis Technique for Air-Gap Eccentricity Fault Diagnosis in Induction Motors

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Chinese Journal of mechanical engineering 2017年第6期30卷 1296-1304页

作者： De Z.Li Wilson Wang Fathy Ismail Department of mechanical engineering Lakehead University Department of mechanical & Mechatronics engineering University of Waterloo

Induction motors （IMs） are commonly used in various industrial applications. To improve energy con- sumption efficiency, a reliable IM health condition moni- toring system is very useful to detect IM fault at its earliest stage to prevent operation degradation, and malfunction of IMs. An intelligent harmonic synthesis technique is pro- posed in this work to conduct incipient air-gap eccentricity fault detection in IMs. The fault harmonic series are syn- thesized to enhance fault features. Fault related local spectra are processed to derive fault indicators for IM air- gap eccentricity diagnosis. The effectiveness of the pro- posed harmonic synthesis technique is examined experi- mentally by IMs with static air-gap eccentricity and dynamic air-gap eccentricity states under different load conditions. Test results show that the developed harmonic synthesis technique can extract fault features effectively for initial IM air-gap eccentricity fault detection.

关键词： Air-gap eccentricity Current signal Faultdetection Induction motor

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Thermo-mechanical properties of bowl-shaped grinding wheel and machining error compensation for grinding indexable inserts

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Journal of Central South University 2015年第10期22卷 3830-3836页

作者：张祥雷姚斌陈彬强孙维方王萌萌罗琪 Department of mechanical and Electrical engineering School of Physics and Mechanical & Electrical EngineeringXiamen University

In order to meet the technical requirements of grinding the circumferential cutting edge of indexable inserts, thermo-mechanical properties of bowl-shaped grinding wheel in high speed grinding process and the influence of dimension variations of the grinding wheel on machining accuracy were investigated. Firstly, the variation trends of the dimension due to centrifugal force generated in different wheel speeds were studied and the effect of stress stiffening and spin softening was presented. Triangular heat flux distribution model was adopted to determine temperature distribution in grinding process. Temperature field cloud pictures were obtained by the finite element software. Then, dimension variation trends of wheel structure were acquired by considering the thermo-mechanical characteristic under combined action of centrifugal force and grinding heat at different speeds. A method of online dynamic monitoring and automatic compensation for dimension error of indexable insert was proposed. By experimental verification, the precision of the inserts satisfies the requirement of processing.

关键词： bowl-shaped grinding wheel thermo-mechanical properties indexable insert machining accuracy compensation

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Visualisation study on water management of cathode dead-ended PEMFC under pressure-swing operation

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Progress in Natural Science:Materials International 2024年第4期34卷 814-823页

作者： Houchang Pei Zhangda Liu Liangbo Sun Beihai Wang Jibin Chen Lu Xing School of mechanical engineering Wuhan Polytechnic University mechanical and Construction engineering Northumbria University

Dead-ended proton exchange membrane fuel cells(PEMFC) using pure hydrogen oxygen can improve fuel efficiency and simplify fuel cell systems have been wildly used for a closed space. But the dead-ended operation of the PEMFC will cause difficulties in water management, especially in the cathode side, resulting in deteriorating of fuel cell stability. For this reason, gravity assisted drainage method, static drainage method are designed to migrate the water out of the cell. However, even with these methods, the reliability of the water removing from the cell remains questionable. Therefore, this paper introduces a novel water removal method to solve these problems and visualisation techniques were used to a more comprehensive knowledge of water transport mechanisms in dead-ended PEMFCs. A pressure-swing operation is realized by controlling the inlet of PEMFC solenoid valve to remove water and recycle oxygen during purging. The dynamic response characteristics of this system under different current densities, pressure differences, cell temperature and purging intervals are experimentally investigated in detail. It found that the water removal rate of the cathode flow channel of dead-ended PEMFC was as high as 99.25 %, and the fuel utilisation of the cell was close to 100 % in this water management mode.

关键词： Visualisation Pressure-swing Dead-ended PEMFC Water management

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Evaluation of mixed mode-Ⅰ/Ⅱ criteria for fatigue crack propagation using experiments and modeling

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Chinese Journal of Aeronautics 2018年第7期31卷 1525-1534页

作者： Oguzhan DEMIR Ali O.AYHAN Sedat IRIC Hüseyin LEKESIZ Department of mechanical engineering Sakarya University Department of mechanical engineering Bilecik S?eyh Edebali University Department of mechanical engineering Bursa Technical University

In this study, in-plane mixed mode-Ⅰ/Ⅱ fatigue crack growth simulations and experiments are performed for the Al 7075-T651 aluminum alloy which is widely used in the aerospace industry. Tests are carried out under different mode mixity ratios to evaluate the applicability of a fracture criterion developed in a previous study to mixed mode-Ⅰ/Ⅱ fatigue crack growth *** obtained from the analyses and experiments are compared with existing and developed criteria in terms of crack growth lives. Compact Tension Shear（CTS） specimens, which enable mixed mode loading with loading devices under different loading angles, are used in the simulations and experiments. In an effort to model and simulate the actual conditions in the experiments, crack surfaces of fractured specimens are scanned, crack paths are modeled exactly, and contacts are defined between the contact surfaces of a specimen and the loading device for each crack propagation step in the analyses. Having computed the mixed mode stress intensity factors from the numerical analyses, propagation life cycles are predicted by existing and the developed mixed mode-Ⅰ/Ⅱ criteria and then compared with experimental results.

关键词： Crack propagation Fatigue crack growth simulation Fatigue crack growth test Fracture mechanics Mixed mode-Ⅰ/Ⅱ

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Numerical Analysis of Chevron Nozzle Effects on Performance of the Supersonic Ejector-Diffuser System

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Journal of Thermal Science 2013年第5期22卷 459-466页

作者： Fanshi Kong Yingzi Jin Toshiaki Setoguchi Heuy Dong Kim College of mechanical engineering & Automation Zhejiang Sci-Tech University School of mechanical engineering Andong National University Department of mechanical engineering Saga University

The supersonic nozzle is the most important device of an ejector-diffuser *** best operation condition and optimal structure of supersonic nozzle are hardly known due to the complicated turbulent mixing,compressibility effects and even flow unsteadiness which are generated around the nozzle *** the present study,the primary stream nozzle was redesigned using convergent nozzle to activate the shear actions between the primary and secondary streams,by means of longitudinal vortices generated between the Chevron *** same geometrical model of ejector-diffuser system was created to validate the results of experimental *** operation characteristics of the ejector system were compared between Chevron nozzle and conventional convergent nozzle for the primary stream.A CFD method has been applied to simulate the supersonic flows and shock waves inside the *** is observed that the flow structure and shock system were changed and primary numerical analysis results show that the Chevron nozzle achieve a positive effect on the supersonic ejector-diffuser system *** ejector with Chevron nozzle can entrain more secondary stream with less primary stream mass flow rate.

关键词： Ejector-Diffuser System Chevron Nozzle Shock Wave Compressible Flow Supersonic Flow

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Adaptive Control of a Flexible Manipulator With Unknown Hysteresis and Intermittent Actuator Faults

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IEEE/CAA Journal of Automatica Sinica 2025年第1期 148-158页

作者： Shouyan Chen Weitian He Zhijia Zhao Yun Feng Zhijie Liu Keum-Shik Hong School of mechanical and Electrical engineering Guangzhou University the School of Control Science and engineering Shandong University IEEE the College of Electrical and Information engineering Hunan University the National engineering Research Center for Robot Visual Perception and Control Technology Hunan University the School of Intelligence Science and Technology University of Science and Technology Beijing (USTB) the Institute for Future the School of AutomationQingdao University the School of mechanical engineering Pusan National University

In this study, we consider a single-link flexible manipulator in the presence of an unknown Bouc-Wen type of hysteresis and intermittent actuator faults. First, an inverse hysteresis dynamics model is introduced, and then the control input is divided into an expected input and an error compensator. Second,a novel adaptive neural network-based control scheme is proposed to cancel the unknown input hysteresis. Subsequently,by modifying the adaptive laws and local control laws, a fault-tolerant control strategy is applied to address uncertain intermittent actuator faults in a flexible manipulator system. Through the direct Lyapunov theory, the proposed scheme allows the state errors to asymptotically converge to a specified interval. Finally,the effectiveness of the proposed scheme is verified through numerical simulations and experiments.

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The analysis of composite laminated beams using a 2D interpolating meshless technique

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Acta Mechanica Sinica 2018年第1期34卷 99-116页

作者： S.H.M.Sadek J.Belinha M.P.L.Parente R.M.Natal Jorge J.M.A.César de Sá A.J.M.Ferreira Department of mechanical engineering Faculty of EngineeringUniversity of Porto Institute of mechanical engineering and Industrial Management University of Porto

Laminated composite materials are widely implemented in several engineering constructions. For its relative light weight, these materials are suitable for aerospace, military, marine, and automotive structural applications. To obtain safe and economical structures, the modelling analysis accuracy is highly relevant. Since meshless methods in the recent years achieved a remarkable progress in computational mechanics, the present work uses one of the most flexible and stable interpolation meshless technique available in the literature—the Radial Point Interpolation Method(RPIM).Here, a 2 D approach is considered to numerically analyse composite laminated beams. Both the meshless formulation and the equilibrium equations ruling the studied physical phenomenon are presented with detail. Several benchmark beam examples are studied and the results are compared with exact solutions available in the literature and the results obtained from a commercial finite element software. The results show the efficiency and accuracy of the proposed numeric technique.

关键词： Radial point interpolators RPIM Laminated beam Meshless method

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Euler-Euler CFD modeling of fluidized bed:Influence of specularity coefficient on hydrodynamic behavior

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Particuology 2013年第6期11卷 673-680页

作者： Chanchal Loha Himadri Chattopadhyay Pradip K.Chatterjee Thermal engineering Group CSIR-Central Mechanical Engineering Research Institute Department of mechanical engineering Jadavpur University

Euler-Euler two-fluid model is used to simulate the hydrodynamics of gas-solid flow in a bubbling flu- idized bed with Geldert B particles where the solid property is calculated by applying the kinetic theory of granular flow （KTGF）. Johnson and Jackson wall boundary condition is used for the particle phase, and different amount of slip between particle and wall is given by varying the specularity coefficient （φ） from 0 to 1. The simulated particle velocity, granular temperature and particle volume fraction are compared to investigate the effect of different wall boundary conditions on the hydrodynamic behavior, Some of the results are also compared with the available experimental data from the literature. It was found that the model predictions are sensitive to the specularity coefficient. The hydrodynamic behavior deviated sig- nificantly for φ = 0 and φ = 0.01 with maximum deviation found at φ = 0 i.e. free-slip condition. However, the overall bed height predicted by all the conditions is similar.

关键词： Fluidized bed Hydrodynamics Specularity coefficient CFD

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