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Effect of Strain Rates on Mechanical Behavior, Microstructure Evolution and Failure Mechanism of Extruded-Annealed Az91 Magnesium Alloy Under Room-Temperature Tension

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SSRN 2023年

作者： Chai, Fang Ma, Zhiyuan Han, Xinghui Hu, Xuan Chang, Zhenyu Zhou, Jianxin Hubei Key Laboratory of Advanced Technology for Automotive Components Wuhan University of Technology Wuhan China Hubei Collaborative Innovation Center for Automotive Components Technology Wuhan University of Technology Wuhan China Hubei Engineering Technology Center for New Energy and Intelligent Connected Vehicles Wuhan University of Technology Wuhan China Hubei Longzhong Laboratory Hubei Xiangyang441000 China State Key Laboratory of Materials Processing and Die & Mould Technology Huazhong University of Science and Technology Wuhan430074 China

Loading rate is usually considered as a significant factor affecting formability of AZ91 magnesium alloy structural components. Herein, uniaxial tensile tests are conducted on extruded-annealed AZ91 alloy under room temperature with strain rates ranging from 1×10-4 s-1 to 1×10-2 s-1. The mechanical properties, microstructure characteristics, and fracture morphologies tensioned at these different strain rates are investigated. Meanwhile, deformation process and atomic microstructures during uniaxial tensile loading is examined through molecular dynamics simulation. Extruded-annealed AZ91 magnesium alloys exhibits a positive strain-rate dependence of strength and a negative strain-rate dependence of elongation, and both strain rate sensitivity and strain-hardening rate under higher strain rate are much higher than those under lower strain rate. The larger strength at higher strain rate is mainly attributed to the more rapid accumulation of dislocation and the larger dislocation density, and the lower elongation at higher strain rate is mostly owing to the more elevated level of inhomogeneous deformation related with dislocations accumulation. As strain rate increases, the area fraction of basal texture increases while that of prismatic and pyramid texture decreases in tensioned samples, which is associated with the dominant room-temperature deformation mode of basal-slip-induced lattice rotation. With tension strain rate increasing, there are three kinds of fracture modes including ductile facture with more and deeper dimples at low strain rate, ductile-brittle facture with some dimples and cleavage planes at mediate strain rate and brittle facture with dominant cleavage planes at high strain rate. © 2023, The Authors. All rights reserved.

关键词： Room temperature

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Effects of Mechanical Vibration on the Heat Transfer Performance of Shell-Tube Heat Exchanger Units During Charging Process

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SSRN 2022年

作者： Zhou, Weiguang Chen, Sheng Mohammed, Hayder I. Hubei Key Laboratory of Advanced Technology for Automotive Components School of Automotive Engineering Wuhan University of Technology Wuhan China Hubei Collaborative Innovation Center for Automotive Components Technology Wuhan China Department of Physics College of Education University of Garmian Kurdistan Iraq

Mechanical vibrations are unavoidable in thermal systems at certain times, but they do not only have a bad effect. This paper presents the first pioneering study of the effect of vibration on the heat transfer performance of tubular heat exchangers. Through numerical simulation methods, by applying mechanical vibrations of different intensities, including different vibration frequencies and vibration amplitudes, the heat transfer enhancement effects of phase change materials under vibrational conditions are fully revealed. The results show that, under lower vibration frequencies (ω = 10 ~ 20), which can significantly promote the mixing of melted PCM and melting heat transfer rate. However, this heat transfer enhancement phenomenon begins to weaken in the case of medium and high frequency vibration frequencies. For all amplitudes, the heat transfer enhancement is markedly stronger than that of frequency, which is linked directly to the magnitude of the amplitude value. In addition, it has been found that the heat transfer enhancement is best when the vibration axis has a small inclination angle to the direction of gravity. These results could fill the research gap regarding the thermal performance of heat exchangers with different geometries under mechanical vibration, also could provide some guidance for future practical applications. © 2022, The Authors. All rights reserved.

关键词： Vibrations (mechanical)

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Trajectory Tracking for Cable-driven Underactuated Manipulator Based on Udwadia-Kalaba Theory

Trajectory Tracking for Cable-driven Underactuated Manipulat...

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Electronic technology, Communication and Information (ICETCI), IEEE International Conference on

作者： Sanbao Hu Xiangsui Jin Hengjia Zhu Hubei Key Laboratory of Advanced Technology of Automotive Components Wuhan University of Technology Wuhan China College of Aeronautical Engineering Civil Aviation University of China Tianjin China

The explicit dynamic model of the cable-driven underactuated manipulator is established to calculate the constraint force by second-order constraints using the Udwadia-Kalaba theory and taking into account the trajectory tracking requirements of the cable-driven underactuated manipulator as the external constraints. Following the decomposition of the constraint force, the analytical expression for the cable tension is obtained. Furthermore, the numerical simulation in MATLAB shows that, when affected by the previously calculated cable tension, the manipulator's tracking trajectory may precisely match the requirements. This approach lessens modeling complexity without the Lagrangian multiplier compared to conventional Lagrangian modeling techniques.

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Simulation and optimization for hydrogen purification performance of vacuum pressure swing adsorption

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Energy Procedia 2019年 158卷 1917-1923页

作者： Wei Tao Shuo Ma Jinsheng Xiao Pierre Bénard Richard Chahine Hubei Key Laboratory of Advanced Technology for Automotive Components and Hubei Collaborative Innovation Center for Automotive Components Technology School of Automotive Engineering Wuhan University of Technology Hubei 430070 China School of Automotive Engineering Wuhan Technical College of Communications Hubei 430065 China Hydrogen Research Institute Université du Québec à Trois-Rivières QC G9A5H7 Canada

A study was performed for hydrogen purification of multicomponent mixture (N 2 /CO/CO 2 /CH 4 /H 2 =0.007/0.012/0.17/ 0.021/0.79) by one-column VPSA with AC5-KS. The performance of the one-column VPSA process can be predicted by a heat and mass transfer model with porous media adsorption. The simulation results agreed well with experimental data. The model was employed to assess the effects of P/F ratio and adsorption time in VPSA unit. The result showed, an increase in P/F ratio and a decrease in feeding time led to an increase in purity of hydrogen and a decrease in recovery. The Sequential Quadratic Programming method was applied to optimize the cycle. The result showed when pressure was set at 5 bar, feed rate was set at 5×10 -5 m 3 /s and P/F ratio was set at 0.3, hydrogen was obtained with a purity of 99.17% and recovery of 58.94% after purification in N 2 /CO/CO 2 /CH 4 /H 2 mixture.

关键词： hydrogen purification vacuum pressure swing adsorption performance heat mass transfer optimization

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iTHD Improvement for TCM Totem Pole PFC Based on WOA Compensated System Delay

iTHD Improvement for TCM Totem Pole PFC Based on WOA Compens...

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Power Energy Systems and Applications (ICoPESA), International Conference on

作者： Di Zhu Chihua Lu Zhien Liu Laifeng Shi Hubei Key Laboratory of Advanced Technology for Automotive Components Wuhan University of Technology Wuhan China Passenger Car Power Center Dongfeng Motor Corporation Wuhan China

ISBN: (数字)9798350351668

ISBN: (纸本)9798350351675

This paper presents a system delay compensation method based on the Whale Optimization Algorithm (WOA) for the triangular current mode(TCM) Totem Pole PFC to improve the input current total harmonic distortion (iTHD). The inherent system delay of the TCM Totem Pole PFC rectifier near the zero-crossing point of the input voltage can cause distortion of the input current. The traditional system delay compensation method is to correct the conduction time of the switch tube with an estimated delay value. However, inaccurate compensation for system delay may lead to poor iTHD improvement or failure to achieve Zero Voltage Switching (ZVS). The method presented in this paper can find the actual system delay value of the rectifier for compensation under different load conditions, to achieve the maximize improvement of iTHD, without affecting ZVS. A simulation model of a 1650W, 220V/450V Totem Pole PFC rectifier was built to test this method. The results show that this method results in an average error of only 0.1055% between the actual and ideal iTHD of PFC.

关键词： Total harmonic distortion Rectifiers Switches Zero voltage switching Distortion Whale optimization algorithms Delays Optimization Load modeling

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Research on Anode Pressure Control and Dynamic Performance of Automotive Fuel Cell System

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SSRN 2023年

作者： Wei, Heng Du, Changqing Li, Xingyi Shi, Chenxu Zhang, Jiaming Hubei Key Laboratory of Advanced Technology for Automotive Components Wuhan University of Technology Wuhan430070 China Hubei Research Center for New Energy & Intelligent Connected Vehicle Wuhan University of Technology Wuhan430070 China Foshan Xianhu Laboratory of the Advanced Energy Science and Technology Guangdong Laboratory Foshan528200 China

The anode pressure supply meeting the system power demand can not only improve the performance output of proton-exchange membrane fuel cell (PEMFC), but also effectively prevent the degradation of proton-exchange membrane (PEM) caused by the fluctuation of anode and cathode pressure. In this article, a practicable feedforward-based proportional-integrative (FFPI) anode pressure control strategy is designed and successfully applied to a 100 kW-class automotive PEMFC system, where the current and anode purging are considered as interferences to apply feedforward compensation. The fuel cell system test bench exhibits good dynamic performance in load change experiments, the cell voltage consistency, power generation efficiency and hydrogen utilization of the system remain at a high level. To further suppress interference and reduce overshoot, oscillation and pressure response hysteresis, a control-oriented model of this 100 kW PEMFC system is constructed, and a novel second-order fuzzy active disturbance rejection controller (SOFADRC) is designed. Simulation results suggest that the proposed SOFADRC is superior than the FFPI controller and the second-order ADRC (SOADRC). The maximum absolute error (MAE), average absolute error (AAE), and root-mean-square error (RMSE) of SOFADRC all reach the minimum values respectively under the step-load and China light-duty vehicle test cycle (CLTC) load conditions, which are 6.51 kPa, 0.09 kPa, 0.42 kPa and 8.95 kPa, 0.62 kPa, 1.35 kPa respectively, showing the outstanding control effect. © 2023, The Authors. All rights reserved.

关键词： Fuzzy logic

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Involvement of Right Superior Frontal in Distracted Driving

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SSRN 2022年

作者： Shi, Changcheng Yan, Fuwu Zhang, Jiawen Yu, Hao Peng, Fuming Yan, Lirong Foshan Xianhu Laboratory of the Advanced Energy Science and Technology Guangdong Laboratory Foshan528200 China Hubei Key Laboratory of Advanced Technology for Automotive Components Wuhan University of Technology Wuhan430070 China Hubei Research Center for New Energy & Intelligent Connected Vehicle Wuhan University of Technology Wuhan430070 China

Differences and correlations in brain area activation between driving distractions (visual, auditory, or cognitive distraction) and normal driving were compared among 30 subjects using electroencephalogram (EEG). Visual, auditory and cognitive subtasks were designed, which occurred randomly during simulated driving, to investigate the effects of different distractions on drivers' neural activities. We found the right intraorbital superior and the infraorbital frontal gyrus were significantly activated during visual distraction. The left and right dorsolateral frontal gyrus were significantly activated during auditory distraction. The right intraorbital superior, infraorbital, and dorsolateral superior frontal gyrus were significantly activated during cognitive distraction. Therefore, prefrontal cortical areas, especially the right frontal cortical area, are most affected by distracted driving. © 2022, The Authors. All rights reserved.

关键词： Electroencephalography

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The Influences of Process Parameters on the Preparation of Closed-cell Aluminum foam by Friction Stir Processing

Research Square

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Research Square 2021年

作者： Pang, Qiu Wu, Zhengjian Hu, Zhili Key Laboratory of Metallurgical Equipment and Control Technology Ministry of Education Wuhan University of Science and Technology Wuhan430081 China Hubei Key Laboratory of Mechanical Transmission and Manufacturing Engineering Wuhan University of Science and Technology Wuhan430081 China Hubei Key Laboratory of Advanced Technology for Automotive Components Wuhan University of Technology Wuhan430070 China

In the present investigation, the closed-cell Al foam was fabricated by friction stir processing (FSP) combined with heat treatment. The influences of process parameters on microstructures of closed-cell Al foam precursor were investigated by optical metallographic microscope and scanning electronic microscope (OM/SEM). Fluent CFD software was developed to simulate the temperature field and flow field in friction stir processing. The cupping test values were compared for base metal and different weld passes. The results show that the welding speeds have little effect on the mixing of powder in the stir zone because of the relatively small welding heat input. However, the pore size and pore morphology are highly sensitive to change in the rotating speeds. When the welding speed is 50mm/min and the rotating speed is 2000rpm, the powder ring is continuous and uniform due to sufficient plastic deformation and flow. When the foaming time is 110s, the expansion rate of the whole foam increases rapidly, and the diameter of the pore is uniform. Numerical simulation shows that the welding heat mainly comes from the shoulder of the stirring head and the welding temperature peak appears near the stirring pin. The maximum flow velocity appears at the outer edge of the shaft shoulder in which the aluminum matrix is softened preferentially. When the rotating speed increases to 2000r/min, the velocity of the outermost edge of the shaft shoulder increases by 59.96%, and the maximum temperature at the stirring pin reaches 491℃ which is consistent with the experimental results. The formability of the joint interface is improved. The cupping test values increase with the increase of deformation temperature. Especially the cupping test value of foamed preform is close to that of base metal at 450℃. © 2021, CC BY.

关键词： Microstructure

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The wear behaviours of G20CrNi2MoA carburised steel under different temperature

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International Journal of Computational Materials Science and Surface Engineering 2020年第2期9卷 134-146页

作者： Zeng, Songwen Qian, Dongsheng Wang, Feng School of Materials Science and Engineering Wuhan University of Technology Wuhan430070 China Hubei Key Laboratory of Advanced Technology for Automotive Components Wuhan430070 China Hubei Engineering Research Center for Green Precision Material Forming Wuhan430070 China

The wear behaviours of G20CrNi2MoA carburised steel under different temperature was investigated in this work. The microstructure and morphology of the worn surface and cross-section of the specimen were characterised by scanning electron microscope (SEM). It is found that the average friction coefficient increases from 0.464 to 0.563 and the wear rate increases from 3.0 × 10–6 mm3N–1m–1 to 21.1 × 10–6 mm3N–1m–1 with the increase of temperature from room temperature (RT) to 200oC. The percentage of oxygen content on the worn surface increases from 11.66% to 36.12% with the increasing temperature, and the main wear mechanism changed from abrasive wear to oxidation wear. The average diameter of the carbides at the subsurface increases from 0.16 μm to 0.24 μm with the increase of temperature. Additionally, the micro crack and voids can be found around the large carbides at 200oC, resulting in the increase of wear rate. Copyright © 2020 Inderscience Enterprises Ltd.

关键词： Carbides

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10-Hz Repetitive Transcranial Magnetic Stimulation over the Frontal Eye Field Modulates Feature-Based Attention

10-Hz Repetitive Transcranial Magnetic Stimulation over the ...

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Intelligent Supercomputing and BioPharma (ISBP), International Conference on

作者： Ningna Li Fuwu Yan Lirong Yan Yibo Wu Biao Xiang Hubei Key Laboratory of Advanced Technology for Automotive Components Wuhan University of Technology Wuhan China Tumxuk Xinguang Jingwei UAV Technology Co. Ltd Tumxuk Xinjiang China

The frontal eye field (FEF) is an important brain area related to visual feature-based attention (FBA). In this study, we applied 10-Hz repetitive transcranial magnetic stimulation (rTMS) to the right FEF (rFEF), designed an improved version of attention network test (ANT) with two attributes (direction and color), to explore the relationship between rFEF and the attentional network (including alerting, orienting and executive control network) and between rFEF and visual FBA. 24 healthy subjects completed the improved ANT after stimulation. The sham stimulation experiment was set as the control group. The experimental results show that the stimuli applied to rFEF can not significantly affect the attention subnetwork. However, rFEF, as a part of the frontoparietal network, affects the relevant connections of the frontoparietal network after a short local stimulation, thereby significantly reducing the reaction time of the subjects. In addition, rFEF is closely related to attribute selection in visual FBA tasks, which has been confirmed.

关键词： Visualization Brain Transcranial magnetic stimulation Color Task analysis

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