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Dynamic microstructure evolution and mechanical properties of dilute Mg-Al-Ca-Mn alloy during hot rolling

Journal of Materials Science & technology 2022年第34期129卷 1-14页

作者： Shiwei Xu Congcong Zhu Zhanhong Lin Chen Jin S.Kamado K.Oh-ishi Yun Qin College of Materials Science and Engineering Hunan UniversityChangsha 410082China State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body Hunan UniversityChangsha 410082China Qinghai Salt Lake Teli Magnesium Co.Ltd. Xining 810000China Department of Mechanical Engineering Nagaoka University of TechnologyNagaoka 940-2188Japan Toyota Central R&D Labs. Inc.41-1 YokomichiNagakuteAichi 480-1192Japan Research Institute(R&D Centre) Baowu Steel Group CorporationShanghai 201900China

The dynamic microstructure and texture of dilute Mg-0.50Al-0.71Ca-0.33Mn(wt.%) during hot rolling at two slab temperatures were investigated by electron backscattered diffraction(EBSD) and high resolution transmission electron microscopy(HRTEM). The results show that the development of the rolling microstructures is to first form {10–12} extension twins in the original grains, thereby forming the extension-twinned regions, and then to further form {10–11}-{10–12} double twins and kinks in the extension-twinned regions, and finally to form continuous dynamic recrystallized(continuous DRXed)grains in the double twins and the cross parts of the shear-deformed coarse extension-twinned *** extension twins, double twins and kinks show a decisive effect on the formation of rolling *** number of {10–11}-{10–12} double twins and resultant the continuous DRX process are strongly affected by the rolling slab temperature and the reduction thickness per pass. By optimizing the rolling conditions, texture and microstructures of the multi-pass rolled Mg-Al-Ca-Mn alloy sheets are successfully modified. Although the total alloy content is only 1.5 wt.%, these Mg-Al-Ca-Mn alloy sheets show much higher strength than the commercial Mg-3Al-1 Zn(wt.%)(AZ31B) sheet.

关键词： Mg-Al-Ca-Mn alloy Hot rolling Dynamic recrystallization Texture control Mechanical properties

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Hierarchical Clustering-Based State Grouping Reinforcement Learning for Switching Decision of Autonomous vehicles

Hierarchical Clustering-Based State Grouping Reinforcement L...

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IEEE International Conference on Unmanned Systems (ICUS)

作者： Wenjie Ouyang Yiwen Jiao Yang Liu Yang Li Manjiang Hu Hongmao Qin College of Mechanical and Vehicle Engineering Hunan University Changsha China College of Computer Science and Electronic Engineering Hunan University Changsha China College of Electrical Mechanical and Computer Science Delft University of Technology Delft The Netherlands State Key Laboratory of Advanced Design and Manufacturing Technology for Vehicle College of Mechanical and Vehicle Engineering Hunan University Changsha China Wuxi Intelligent Control Research Institute of Hunan University Wuxi China

Reinforcement learning (RL) has gained wide attention, but its implementation in autonomous vehicles is still limited by insufficient sample efficiency and heavy training costs. The training efficiency of RL agents is influenced by the dimension of the state space, which can be partitioned to reduce the complexity of sampling and computation. This study proposes a hierarchical clustering-based state grouping reinforcement learning (HCSG-RL) method for the switching decision of autonomous vehicles. First, we partition the base state space into groups and generate a hierarchical tree of state space groups. Then, we train multiple sub-agents for each node in the hierarchical tree. Finally, we add these trained-well sub-model into master policy. This method allows us to fully explore all state spaces and improve the training efficiency of individual agents, which handles the “long-tail” issue and the curse of dimensionality issue. We conduct experiments in a simulation environment and results show that the proposed method has 16–72% reward improvement compared to the tree model in different road length.

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Model Predictive Control Assisted Energy Management Strategy for Hybrid Mining Dump Trucks Based on Speed and Slope Prediction

SSRN

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SSRN 2024年

作者： Xie, Guojin Qin, Hongmao Xie, Heping Bian, Yougang Ding, Rongjun State Key Laboratory of Advanced Design and Manufacturing Technology for Vehicle College of Mechanical and Vehicle Engineering Hunan University Hunan Changsha410082 China School of Mechanical and Automotive Engineering Guangxi University of Science and Technology Guangxi Liuzhou545616 China Wuxi Intelligent Control Research Institute of Hunan University Wuxi214115 China Xuzhou XCMG Mining Machinery Co. Ltd. Xuzhou210009 China

Based on the basic principles of model predictive control, the energy management and optimal control problems of large-scale mining hybrid dump trucks are studied. This paper presents an artificial neural network model to predict the vehicle speed and road slope in the predictive horizon. Based on the predicted information and the vehicle dynamics model, the future power demand of the vehicle is calculated, and a fuel economy optimization objective function is established to minimize the set objective function value under the condition of multiple system constraints, which is solved through dynamic programming algorithm (DP) rolling optimization in the finite predictive horizon to realize optimal energy allocation between the engine generator and battery pack. The vehicle speed and road slope are predicted in 5 different horizons to determine the optimal prediction horizon under the conditions of flat and slope roads. A prediction model is constructed, and combined with the vehicle system and dynamic model, a DP-MPC energy management strategy for series hybrid electric vehicle (SHEV) is designed, and the advantages and disadvantages of the strategy are evaluated through offline simulation testing. Finally, the effectiveness and real-time performance of the energy management strategy are verified through HIL experiments under different operating conditions. © 2024, The Authors. All rights reserved.

关键词： Model predictive control

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Model Predictive Control Assisted Energy Management Strategy for Hybrid Mining Dump Trucks Based on Speed and Slope Prediction

SSRN

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SSRN 2024年

关键词： Model predictive control

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Two-Stage Retired Battery Sorting Strategy Based on Multi-Feature Fusion

Two-Stage Retired Battery Sorting Strategy Based on Multi-Fe...

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Conference on vehicle Control and Intelligence (CVCI)

作者： Rui Pan Xiangyu Xiao Zhuo Liu Duo Yang Juan Zhou School of Automation and Electronic Information Xiangtan University Xiangtan China School of Electrical and Information Engineering Zhengzhou University Zhengzhou China State Key Laboratory of Advanced Design and Manufacturing Technology for Vehicle Hunan University Changsha China

ISBN: (数字)9798331504892

ISBN: (纸本)9798331504908

Scale retirement of lithium-ion batteries has brought about the issue of their gradient utilization, and the consistency sorting technology is the key to it. However, the existing consistency sorting technology has a single sorting feature, low sorting effectiveness and other problems. This paper proposes a two-stage decommissioning lithium battery sorting method. The overall partial correlation coefficient analysis of the features is carried out to determine the sorting features. In the first stage, DBSCAN performs multiple clustering for different combinations of features to cross-validate the results and exclude abnormal batteries. In the second stage, the cohesive hierarchical clustering algorithm sorts retired batteries, and the number of clusters is determined by observing the dendrogram. The results show that the standard deviation of the capacity of the battery clusters is reduced by at least 48.19%; the standard deviation of the internal resistance is reduced by at least 36%; and the standard deviation of the OCV is reduced by at least 29% relative to that before the unsorted, proving the effectiveness of the proposed method.

关键词： Resistance Correlation coefficient Measurement Lithium-ion batteries Lithium batteries Batteries safety Standards Retirement Sorting

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The Effect of Asynchronous Intake Valve Opening Strategy Coupled with Egr Addition on the Cycle-by-Cycle Variations of Miller Engine with Different High Compression Ratios

SSRN

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SSRN 2024年

作者： Qiao, Junhao Liu, Jingping Jia, Dongdong Wang, Rumin Fu, Jianqin Duan, Xiongbo State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body Hunan University Changsha410082 China Hunan Dazi Power Technology Co. Ltd Changsha410221 China School of Energy Science and Engineering Central South University Changsha410083 China

A novel design of the Miller cycle (MC) achieved by the asynchronous intake valve is adopted in the test spark ignition (SI) engine with different high compression ratios (CR12.5 and CR14.5). The influences of compression ratio (CR12.5 and CR14.5) and asynchronous intake valve Miller cycle (AIVMC) on the combustion cycle-to-cycle variations (CCV) of a GDI baseline engine are conducted and compared to the original Otto cycle (OC). Meanwhile, the influences of EGR strategy on the CCV, combustion phase and emissions of the modified engine with AIVMC are also discussed. Results show that using AIVMC can realize Miller cycle by adjusting the timing of variable valve. Moreover, the high geometric compression ratio SI engine equipped with AIVMC not only reduces the cyclic variation at low load compared with the OC cycle, but also optimizes combustion phase because of superior anti-knock ability, which improves operating stability and reduce fuel consumption. In addition, coupling application of AIVMC and EGR strategy in test SI engine enhances engine knock tolerance. Besides, using the EGR and AIVMC in the test SI engine can significantly reduce NOx emissions compared to only use the AIVMC. Meanwhile, the NOx emissions gain a reduction of 68.7% with using EGR. © 2024, The Authors. All rights reserved.

关键词： Intake valves

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Wave-graphene: a full-auxetic carbon semiconductor with high flexibility and optical UV absorption

arXiv

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arXiv 2024年

作者： Yu, Linfeng Zhang, Yi Lin, Jianzhou Dong, Kexin Zheng, Xiong Qin, Zhenzhen Qin, Guangzhao State Key Laboratory of Advanced Design and Manufacturing Technology for Vehicle College of Mechanical and Vehicle Engineering Hunan University Changsha410082 China School of Physics and Microelectronics Zhengzhou University Zhengzhou450001 China Research Institute of Hunan University in Chongqing Chongqing401133 China Greater Bay Area Institute for Innovation Hunan University Guangdong Province Guangzhou511300 China

The abundant bonding possibilities of Carbon stimulate the design of numerous carbon allotropes, promising the foundation for exploring structure-functionality relationships. Herein, utilizing the space bending strategy, we successfully engineered a two-dimensional carbon allotrope with pure sp2 hybridization, named "Wave-graphene" from the unique wave-like ripple structure. The novel Wave-graphene exhibits full-auxetic behavior due to anisotropic mechanical response, possessing both negative and zero Poisson's ratios. The fundamental mechanism can be attributed to the fact that highly buckled out-of-plane structures lead to anisotropic responses of in-plane nonlinear interactions, which further lead to anisotropy of lattice vibrations. In addition, Wave-graphene is found having quasi-direct wide bandgap of 2.01 eV, the excellent optical transparency and the high flexibility. The successful design of Wave-graphene with excellent outstanding multifunctional properties shows that the utilization of space bending strategies can provide more degrees of freedom for designing novel materials, further enriching the carbon material family and supplementing its versatility. Copyright © 2024, The Authors. All rights reserved.

关键词： Graphene

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reliability-Aware Vehicular Communication and Mobility Optimization: Joint Data Transmission Scheduling and Motion Planning

Reliability-Aware Vehicular Communication and Mobility Optim...

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2022 IEEE International Conference on Unmanned Systems, ICUS 2022

作者： Xu, Gangchuan Zhou, Jianshan Tian, Daxin Ren, Chenghao Duan, Xuting Sheng, Zhengguo School of Transportation Science and Engineering Beihang Beijing Key Laboratory for Cooperative Vehicle Infrastructure Systems and Safety Control Beijing100191 China Zibo Vaucrefly Intelligent Technology Co. Ltd. Zibo255000 China University of Sussex Department of Engineering and Design Richmond United Kingdom

ISBN: (数字)9781665484565

ISBN: (纸本)9781665484565

Motion planning and vehicular communication are two enabling technologies for the practical realization of connected autonomous vehicles (CAVs), However, few studies have recently provided an effective systematic design from a joint optimization perspective. In our research, we present an optimization system that joins the reliability-oriented cellular vehicle-to-infrastructure communication (V2I) and the multi-objective motion planning into a model predictive control (MPC) model. We propose a stochastic model characterizing the V2I communication reliability and an optimization cost function for the motion planning of a CAV regarding control energy consumption, mobility efficiency, and smoothness. The system model is to maximize the V2I communication reliability meanwhile minimizing the motion cost by jointly optimizing the velocity and data transmission of the vehicle. Using an E-constraint method, we transform the multi-objective optimization model into a tractable problem and propose a numerical optimization algorithm to solve it. Simulation results demonstrate the validity of our joint optimization method for reliability-guaranteed vehicular communication and optimal motion planning and its performance outperforms several baselines. © 2022 IEEE.

关键词： Motion planning

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Enhanced Ablation Resistance of Carbon Fiber Reinforced Phenolic Composites Through designing In-Plane Heat Conduction And Out-of-Plane Heat Insulation Channels

SSRN

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SSRN 2024年

作者： Chen, Xiang Shi, Kui Gu, Ziwen Quan, Huafeng Huang, Dong Zhang, Yuefeng Li, Tongqi Ye, Chong Fan, Zhen Zhu, Shipeng Liu, Jinshui Peng, Chaoyi Tao, Lei College of Materials Science and Engineering Hunan Province Key Laboratory for Advanced Carbon Materials and Applied Technology Hunan University Changsha410082 China Hunan Province Engineering Research Center for High Performance Pitch-based Carbon Materials Hunan Toyi Carbon Material Technology Co. Ltd. Changsha410000 China Key Laboratory of Advanced Functional Composite Materials Aerospace Research Institute of Materials and Processing Technology Beijing100076 China State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body Hunan University Changsha410082 China Zhuzhou Times New Material Technology Co. Ltd. Zhuzhou412007 China China Academy of Launch Vehicle Technology China

With the development of near-space vehicles toward higher Mach speeds, the aerodynamic heating problem poses an increasingly serious challenge to thermal protection system, and thus it is urgent to further improve the ablation resistance of carbon fiber reinforced phenolic resin (CF/PR). To achieve this, an innovative composite was prepared using mesophase-pitch-based carbon fiber as a reinforcement to construct the in-plane heat transfer channels. The thermal conductivities of composite in in-plane (λi) and out-of-plane (λo) directions were 24.37 W·m-1·K-1 and 0.96 W·m-1·K-1, respectively, and the ratio(λi/λo) is up to 25.39, which plays a positive role in enhancing the heat dissipation of ablation center while maintaining effective interlayer insulation. During ablation, the composite exhibits a 159 °C lower stagnation-point temperature compared to the control group, and the maximum and average temperature on its backside decrease 196 °C and 201 °C, respectively. Consequently, the mass ablation rate and the line ablation rate of composite are reduced by 72.5% and 87.6%, respectively. The anisotropic thermal behavior and higher λi/λo value contribute to the decrease of the stagnation-point temperature, the maximum temperature and the average temperature on the backside, thereby improving the ablation resistance of composite. © 2024, The Authors. All rights reserved.

关键词： Ablation

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Correction: Ultrathin high-performance electromagnetic wave absorbers with facilely fabricated hierarchical porous Co/C crabapples (Journal of Materials Chemistry C (2019) 7 (1659-1669) DOI: 10.1039/C8TC04984J)

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Journal of Materials Chemistry C 2025年第23期13卷 12025-12026页

作者： Nannan Wu Chang Liu Dongmei Xu Jiurong Liu Wei Liu Hu Liu Jiaoxia Zhang Wei Xie Zhanhu Guo Key Laboratory for Liquid–Solid Structural Evolution and Processing of Materials Ministry of Education and School of Materials Science and Engineering Shandong University Jinan Shandong 250061 China Integrated Composites Laboratory (ICL) Department of Chemical & Biomolecular Engineering University of Tennessee Knoxville TN 37996 USA State Key Laboratory of Crystal Materials Shandong University Shandong 250100 China Key Laboratory of Materials Processing and Mold (Zhengzhou University) Ministry of Education National Engineering Research Center for Advanced Polymer Processing Technology Zhengzhou University Zhengzhou China School of Material Science and Engineering Jiangsu University of Science and Technology Zhenjiang Jiangsu China Key Laboratory of Lightweight and Reliability Technology for Engineering Vehicle Education Department Changsha University of Science & Technology Changsha Hunan China

The authors regret the following errors in the published article: In the originally published supplementary information document, Fig. S1a, S5c and S6d were images of the same sample obtained at optimal conditions. In order to avoid misleading readers, the original Fig. S5c and S6d have been replaced by new images captured at different places of the same sample. In addition, an error was found in the Fig. S6 caption: the PVP amount for both Fig. S6a and b should be 0 g. The corrected versions of Fig. S5 and S6 are shown below. In the "Results and discussion" section of the published article, on page 1662 of the pdf, the related description of Fig. S6 should be corrected as follows: "Numerous scattered flakes and only a few a-Co(OH)2 crabapples were obtained without the addition of PVP (Fig. S6a and b, ESI)." The supplementary information document has been updated with these changes. (Figure presented) In Fig. 2 in the published article, an error occurred when assembling the images: Fig. 2b and e were inadvertently swapped. The accompanying calculations and the following descriptions used the correct data and thus are not affected. The corrected Fig. 2 is shown in this notice. Related to this, on page 1664 of the pdf, the related text remains almost constant with some fluctuations..." should be replaced with remains almost constant despite fluctuations from 13.6-14.4 GHz...". In addition, "For sample M30, a sharp decrease of in the frequency range of 12-18 GHz occurs while the corresponding shows a resonance peak,. . ." should be replaced with "For sample M30, a decrease of occurs while the shows a resonance peak in the frequency range of 12-18 GHz,. . .". In addition, on page 1665 of the pdf, the sentence "The SBET for hierarchical porous Co/C crabapples is 68.4 m2 g-1" should be corrected to "The SBET for hierarchical porous Co/C crabapples is 64.4 m2 g-1" after rechecking the raw data. It should be noted that the conclusions of the work are not affected by these c

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