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Defect band formation in high pressure die casting AE44 magnesium alloy

China Foundry 2022年第3期19卷 201-210页

作者： Ying-ying Hou Meng-wu Wu Feng Huang Xiao-bo Li Shou-mei Xiong Hubei Key Laboratory of Advanced Technology for Automotive Components Wuhan University of TechnologyWuhan 430070China School of Materials Science and Engineering Tsinghua UniversityBeijing 100084China

The characteristics of defect bands in the microstructure of high pressure die casting(HPDC)AE44 magnesium alloy were *** attention was paid to the effects of process parameters during the HPDC process and casting structure on the distribution of defect *** show that the defect bands are solute segregation bands with the enrichment of Al,Ce and La elements,which are basically in the form of Al_(11)RE_(3) *** is no obvious aggregation of porosities in the defect *** width of the inner defect band is 4-8 times larger than that of the outer *** variation trends of the distribution of the inner and outer defect bands are not consistent under different process parameters and at different locations of *** is due to the discrepancy between the formation mechanisms of double defect *** filling and solidification behavior of the melt near the chilling layer is very complicated,which finally leads to a fluctuation of the width and location of the outer defect *** affecting the content and aggregation degree of externally solidified crystals(ESCs)in the cross section of die castings,the process parameters and casting structure have a great influence on the distribution of the inner defect band.

关键词： high pressure die casting magnesium alloy AE44 defect band microstructure

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Impacts of porous material fluid bulk properties on noise attenuation performance of cylinder shell structure based on finite element model

Impacts of porous material fluid bulk properties on noise at...

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作者： Li, Bin Li, Jian Yan, Shilin Ju, Linfeng He, Xu Hubei Key Laboratory of Theory and Application of Advanced Materials Mechanics Wuhan430070 China Guangxi Key Laboratory of Automobile Components and Vehicle Technology Liuzhou545006 China

The noise control method of laying acoustic blanket is adopted to construct a cylinder cell noise experimental device;a typical porous material, melamine foam (MF), is used for noise attenuation experiments in aluminum (Al) and aluminum/melamine foam (Al/MF) cylinder shells and to achieve corresponding in-shell noise response spectrograms. Based on the Virtual Lab acoustics software, a finite element model has established for the analysis of noise in the Al/MF cylinder shell and numerical simulation computation has been conducted for the acoustic mode and in-shell acoustic response;the correctness of the finite element model is verified via comparison with theoretical and measured data. On this basis, the impacts of porous material fluid bulk properties on the noise attenuation effect of the Al/MF cylinder shell are further studied within the frequency range of 0 ∼ 1000 Hz. It is suggested that fluid bulk properties changes pose relatively high impacts on internal noise response of a cylindrical cavity. Within low-frequency and high-frequency ranges, the response value of sound pressure increases with flow resistivity, while the response value of sound pressure decreases with the increases of tortuosity, porosity, flow resistivity (only for the medium frequency range), and viscous characteristic length in the medium and high frequencies ranges. © 2018 John Wiley & Sons, Ltd.

关键词： Aluminum

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Picosecond laser ultrasonic imaging detection of near-surface micro defects using PCS and SAFT algorithm

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Ultrasonics 2025年

作者： Kangwen Huang Xiaokai Wang Shutong Dai Yu Peng Yan Zeng Lin Hua Shanyue Guan Hubei Key Laboratory of Advanced Technology for Automotive Components Wuhan University of Technology Wuhan 430070 China Hubei Collaborative Innovation Center for Automotive Components Technology Wuhan University of Technology Wuhan 430070 China School of Automotive Engineering Wuhan University of Technology Wuhan 430070 China College of Power Engineering Naval University of Engineering Wuhan 430030 China

The effective detection and imaging of near-surface micro defects has been the key problem in the ultrasonic inspection field for a long time. Laser ultrasound has high resolution and sensitivity which is the effective technology to detect micro defects. In this paper, the time and frequency domain characteristics of the picosecond laser ultrasound and the interaction mechanism between micro defects and ultrasonic waves are studied by simulation and experiment. A picosecond pulsed laser is used to excite ultrasonic waves in samples with near-surface micro defects of different depths, and the propagating ultrasonic waves are detected by an optical interferometer. Through the analysis of the experimental results, the near-surface micro defects with diameters of 0.13 mm and depths of 0.3 mm, 0.5 mm, 1 mm and 2 mm can be detected. In addition, a defect imaging algorithm combining principal component subtraction (PCS) and synthetic aperture focusing technique (SAFT) is proposed, which can effectively suppress the detection blind areas and artifacts caused by Rayleigh (R)-wave interference. Compared with the conventional total focusing method (TFM) of water-immersion ultrasound, the average SNR is increased by 25.57 dB. This research is poised to contribute to the resolution of quality assessment challenges in product manufacturing and service processes.

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The effects of nucleation on soot dynamic evolution based on the method of moments

The effects of nucleation on soot dynamic evolution based on...

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3rd International Conference on Mechanical Automation and Materials Engineering, ICMAME 2014

作者： Liu, Jin Ping Wei, Ming Rui Xiao, He Lin Peng, Fei School of Automobile Engineering Wuhan University of Technology Wuhan 430070 China Hubei Key Laboratory of Advanced Technology for Automotive Components Wuhan China Hubei Collaborative Innovation Center for Automotive Components Technology Wuhan China

ISBN: (纸本)9783038350941

The mathematical model of soot dynamical evolution process is built based on the discrete particles population balance theory, including particle nucleation, collision coagulation, oxidation and surface growth processes;a corresponding numerical model is established using Lagrange interpolation method of moments. Based on the perfectly-stirred reactor combustion model, coupled the numerical model with detailed chemical kinetic model. The computing platform of soot particle growth evolution is established. Meanwhile, three nucleation models are built for the soot nucleation in this paper. Two chemical reaction mechanisms are used to study different fuels combustion process. The related information of soot particle growth evolution is obatained, the effect of different nucleation model on other dynamical events such as coagulation, oxidation and surface growth processes is discussed. © (2014) Trans Tech Publications, Switzerland.

关键词： Method of moments

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Application of novel force control strategies to enhance robotic abrasive belt grinding quality of aero-engine blades

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Chinese Journal of Aeronautics 2019年第10期32卷 2368-2382页

作者： Xiaohu XU Dahu ZHU Haiyang ZHANG Sijie YAN Han DING State Key Laboratory of Digital Manufacturing Equipment and Technology Huazhong University of Science and TechnologyWuhan 430074China Hubei Key Laboratory of Advanced Technology for Automotive Components Wuhan University of TechnologyWuhan 430070China Hubei Collaborative Innovation Center for Automotive Components Technology Wuhan University of TechnologyWuhan 430074China Wuxi CRRC Times Intelligent Equipment Co. Ltd.Wuxi 214174China

Robotic belt grinding has emerged as a finishing process in recent years for machining components with high surface finish and *** surface machining consistency,however,is difficult to be guaranteed in such a *** overcome this problem,a method of hybrid force-position control combined with PI/PD control is proposed to be applied in robotic abrasive belt grinding of complex *** signals are firstly obtained and transformed to force information with signal conditioning ***,zero drift and gravity compensation algorithms are presented to calibrate the F/T transducer which is installed on the robot ***,a force control strategy combining hybrid force-position control with PI/PD control is introduced to be employed in robotic abrasive belt grinding operations where the force control law is applied to the Z direction of the tool frame and the positon control law is used in the X direction of the tool ***,the accuracy of the F/T transducer and the robotic force control system is analyzed to ensure the stability and reliability of force control in the robotic grinding ***,two typical cases on robotic belt grinding of a test workpiece and an aero-engine blade are conducted to validate the practicality and effectiveness of the force control technology proposed.

关键词： Gravity compensation Hybrid force-position control PI/PD control Robotic belt grinding Zero drift compensation

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Soft measurement model of ring's dimensions for vertical hot ring rolling process using neural networks optimized by genetic algorithm

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Journal of Central South University 2017年第1期24卷 17-29页

作者：汪小凯华林汪晓旋梅雪松朱乾浩戴玉同 Hubei Key Laboratory of Advanced Technology for Automotive Components Wuhan University of TechnologyWuhan 430070China College of Mechanical Engineering Xi'an Jiaotong UniversityXi'an 710049China Hubei Collaborative Innovation Center for Automotive Components Technology Wuhan 430070China National Automobile Quality Supervision Test Center Xiangyang 441004China Zhangjiagang Hailu Annular Forgings Co. Ltd.Zhangjiagang 215626China

Vertical hot ring rolling(VHRR) process has the characteristics of nonlinearity,time-variation and being susceptible to ***,the ring's growth is quite fast within a short time,and the rolled ring's position is *** of these cause that the ring's dimensions cannot be measured *** analyzing the relationships among the dimensions of ring blanks,the positions of rolls and the ring's inner and outer diameter,the soft measurement model of ring's dimensions is established based on the radial basis function neural network(RBFNN).A mass of data samples are obtained from VHRR finite element(FE) simulations to train and test the soft measurement NN model,and the model's structure parameters are deduced and optimized by genetic algorithm(GA).Finally,the soft measurement system of ring's dimensions is established and validated by the VHRR *** ring's dimensions were measured artificially and calculated by the soft measurement NN *** results show that the calculation values of GA-RBFNN model are close to the artificial measurement *** addition,the calculation accuracy of GA-RBFNN model is higher than that of RBFNN *** research results suggest that the soft measurement NN model has high precision and *** research can provide practical methods and theoretical guidance for the accurate measurement of VHRR process.

关键词： vertical hot ring rolling dimension precision soft measurement model artificial neural network genetic algorithm

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Control Strategy Research of a Selective Catalytic Reduction System for Heavy-Duty Application

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Journal of Shanghai Jiaotong university(Science) 2017年第5期22卷 577-588页

作者：王天田林峰胡杰柯于强张岳秋 Hubei Key Laboratory of Advanced Technology for Automotive Components & Hubei Collaborative Innovation Center for Automotive Components Technology Wuhan University of Technology Dongfeng Liuzhou Motor Co. Ltd. Beijing Municipal Vehicle Emission Management Center

An AdBlue dosing control strategy of the selective catalytic reduction (SCR) system is developed for a heavy-duty diesel (HDD) engine. The strategy includes a raw emission prediction model, an ammonia (NH3) coverage prediction model, a transient heat hysteresis correction algorithm, an NH3 leakage control model for transient operation conditions, and a feedback controller (FBC). FBC has been developed by using mathematical manipulation to change output signal of sensor based on cross-sensitivity of nitrogen oxide (NOx) sensor to NH3. The quantification of control parameters is based on experiments and Nyquist stability criterion. FBC is enabled in most test conditions to satisfy the stability requirements. NOxconversion (DeNOx) efficiency of SCR system is 82.4% in European steady-state cycle (ESC) test and 80.3% in European transient cycle (ETC) test, while the leakage of NH3 is under 10−5volume fraction in average. © 2017, Shanghai Jiaotong University and Springer-Verlag GmbH Germany.

关键词： Nitrogen oxides Stability criteria

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Fusion method aiming at environmental perception of autonomous vehicle based on visual scheme

Fusion method aiming at environmental perception of autonomo...

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2024 International Conference on Optics, Electronics, and Communication Engineering, OECE 2024

作者： Tu, Gepeng Wu, Jing Liu, Bo Wang, Xinyu Wuhan University of Technology Hubei Key Laboratory of Advanced Technology for Automotive Components Hubei Wuhan430070 China

ISBN: (纸本)9781510685437

The task of environmental perception is an extremely important part of the automatic driving project, and mainstream schemes are divided into visual perception and radar perception. Visual algorithms have advantages in cost and object detection or image segmentation methods are usually used for perception. We adopt computer vision scheme to collect data and establish Transportation of Wuhan China (TOWC) datasets based on Chinese urban situation. After optimizing the selection of anchor boxes, the Yolov4 model is retrained as the object detector, which is combined with Simple Online and Real-time Tracking (SORT) algorithm and Perspective-n-Point (PnP) monocular algorithm to realize the integration of object detection, tracking. The detection and tracking methods have been evaluated against the Microsoft Common Objects in Context (MSCOCO) datasets and Multiple Object Tracking (MOT) challenge respectively. And the detection performance also has been evaluated again in our TOWC datasets. The evaluation has been conducted in challenging conditions, including occlusion, partial visibility, and under lighting variations with the mean average precision of 97.17% and the real-time speed of 30.2 FPS. The results show that our fusion detection algorithm is not inferior to other most advanced methods on the premise of excellent real-time performance. The developed model is a generic and accurate solution for traffic object detection and tracking, which can be applied to many other fields, such as automatic driving vehicle, traffic sign recognition, anomaly detection, motion analysis, or any other research areas where the traffic environmental perception is in the center of attention. © 2024 SPIE.

关键词： Traffic signs

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In situ synthesis of a porous high-Mn and high-Al steel by a novel two-step pore-forming technique in vacuum sintering

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Journal of Materials Science & technology 2020年第4期39卷 82-88页

作者： Chuanbing Zhuang Zhigang Xu Shangyu Huang Yu Xia Chuanbin Wang Qiang Shen Hubei Key Laboratory of Advanced Technology for Automotive Components Wuhan University of TechnologyWuhan 430070China Hubei Collaborative Innovation Center for Automotive Components Technology Wuhan University of TechnologyWuhan 430070China School of Materials Science and Engineering Wuhan University of TechnologyWuhan 430070China State Key Lab of Advanced Technology for Materials Synthesis and Processing Wuhan University of TechnologyWuhan 430070China Hubei Engineering Research Center for Green Precision Materials Forming Wuhan University of TechnologyWuhan 430070China

In this work, a novel in-situ two-step pore-forming process in vacuum sintering(ITPVS) technique combining low-temperature processing to produce open pores through the interdiffusion among the intrinsic components in the base steel, and subsequent high-temperature processing to further improve the porosities by the sublimation of Mn via previously formed open pores, was proposed to produce a lab-scale porous Fe Mn Al steel. For the first time, a high-Mn and high-Al steel with open and overall porosities of ~59.6 vol.% and ~63.7 vol.%(percent in volume, vol.%) was synthesized by isothermal holding of the quaternary elemental Fe/Mn/Al/C powder mixture at 640℃ for 1 h and the subsequent sintering at 1200℃ for 1 h. Elemental Al partly incorporated into/reacted with α-Fe and α-Mn after sintering at640℃ for 1 h, leading to the overall and open porosities promoting by ~26.6 vol.% and ~25.6 vol.%. After sintering at 1200℃, Fe Mn Al steel with increased porosities mainly comprising of austenite and α-Fe obtained. The compression strength and corresponding strain of the 1200℃-sintered porous specimen without crack on the surface was ~75 MPa and ~25%. The ITPVS technique takes advantage of using the intrinsic components like Al, Mn and Fe in steels to produce porous structure. This is beneficial to avoiding the contamination of the Fe Mn Al steel matrix caused by the employment of the foreign pore-forming agents.

关键词： Porous metal High manganese steel Two-stage sintering Reaction-diffusion Sublimation method

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Doping strategy on improving the overall cathodic performance of double perovskite LnBaCo_(2)O_(5+σ)(Ln=Pr,Gd)as potential SOFC cathode materials

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Journal of Materiomics 2023年第5期9卷 825-837页

作者： Fangze Chen Dacheng Zhou Xueqing Xiong Juntao Pan Donglin Cai Ze Wei Xiyong Chen Yihui Liu Nengneng Luo Jialin Yan Toyohisa Fujita State Key Laboratory of Featured Metal Materials and Life-cycle Safety for Composite Structures Guangxi UniversityNanning530004GuangxiChina School of Resources Environment and MaterialsGuangxi UniversityNanning530004GuangxiChina Hubei Key Laboratory of Advanced Technology for Automotive Components&Hubei Collaborative Innovation Center for Automotive Components Technology Wuhan University of TechnologyWuhan430070HubeiChina

A series of single-phase double perovskite Pr1-xGdxBaCo_(2)-yFeyO_(5+σ)(x=0,0.5 and 1,0≤y≤1)materials were engineered through A/B site co-doping strategy to improve the mechanical,electrical and electrochemical properties as potential cathode materials for the application of intermediate solid oxide fuel cells(IT-SOFCs).The corresponding thermochemical stability,thermal expansion behavior,electrical conductivity and cathodic polarization resistance of the materials were systematically *** was found that the A-site dual lanthanide doped Pr_(0.5)Gd_(0.5)BaCo_(2)O_(5+σ)(PGBCO)exhibits improved electrical conductivity,reduced thermal expansion,and comparatively low electrochemical polarization resistance versus single lanthanide double perovskite,PrBaCo_(2)O_(5+σ)(PBCO)and GdBaCo_(2)O_(5+σ)(GBCO)*** investigation on the effect of B-site Fe-doping on Pr_(0.5)Gd_(0.5)BaCo_(2)-yFeyO_(5)+σ(PGBCF-y,0≤y≤1)reveals that all the PGBCF-y compositions exhibit excellent chemical stability with Gd-doped ceria(GDC)at operating temperatures not higher than 1100℃.Besides,doping of Fe in B-site can effectively reduce the thermal expansion coefficients(TECs)of the Pr_(0.5)Gd_(0.5)BaCo_(2)O_(5)+σceramics at 30e1000℃.And the electrochemical impedance spectra(EIS)results show that the PGBCF-y|GDC|PGBCF-y symmetric cells have acceptable low area specific polarization *** examination of the cathodic polarization and characteristic capacitance from the AC impedance spectra by employing the relaxation time distribution(DRT)method demonstrated that charge transfer is the dominating subprocess for the oxygen transport through the materials.

关键词： Double perovskite Electrical conductivity Thermal expansion Electrochemical polarization Thermochemical stability

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