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Tuning mechanical behaviors of highly entangled hydrogels with the random distribution of mobile entanglements

Applied Mathematics and Mechanics(English Edition) 2024年第2期45卷 277-294页

作者： Jinlong LIU Di LU Bin CHEN Department of Engineering Mechanics Zhejiang UniversityHangzhou 310027China Beijing System Design Institute of Electro-Mechanic Engineering Beijing 100854China Intelligent Robotic Research Center Zhejiang LaboratoryHangzhou 310027China Key Laboratory of Soft Machines and Smart Devices of Zhejiang Province Hangzhou 311100China

Highly entangled hydrogels exhibit excellent mechanical properties,including high toughness,high stretchability,and low *** considering the evolution of randomly distributed entanglements within the polymer network upon mechanical stretches,we develop a constitutive theory to describe the large stretch behaviors of these *** the theory,we utilize a representative volume element(RVE)in the shape of a cube,within which there exists an averaged chain segment along each edge and a mobile entanglement at each *** employing an explicit method,we decouple the elasticity of the hydrogels from the sliding motion of their entanglements,and derive the stress-stretch relations for these *** present theoretical analysis is in agreement with experiment,and highlights the significant influence of the entanglement distribution within the hydrogels on their *** also implement the present developed constitutive theory into a commercial finite element software,and the subsequent simulations demonstrate that the exact distribution of entanglements strongly affects the mechanical behaviors of the structures of these ***,the present theory provides valuable insights into the deformation mechanism of highly entangled hydrogels,and can aid in the design of these hydrogels with enhanced performance.

关键词： highly entangled hydrogel constitutive theory entanglement gamma distribution

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An interval finite element method based on bilevel Kriging model

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Chinese Journal of Aeronautics 2024年第12期37卷 1-11页

作者： Zhongyang YAO Shaohua WANG Pengge WU Bingyu NI Chao JIANG State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body College of Mechanical and Vehicle EngineeringHunan UniversityChangsha 410082China Flight Automatic Control Research Institute of AVIC Xi’an 710065China Agriculture Equipment Institute of Hunan Hunan Academy of Agricultural SciencesChangsha 410125China

This study introduces a new approach utilizing an interval finite element method combined with a bilevel Kriging model to determine the bounds of structural responses in the presence of spatial uncertainties.A notable benefit of this approach is its ability to determine the response bounds across all degrees of freedom with a small sample size,which means that it has high ***,the spatially varying uncertain parameters are quantified using an interval field model,which is described by a series of standard interval variables within a truncated interval Karhunen-Loe`ve(K-L)series ***,considering that the bound of structural response is a function of spatial position with the property of continuity,a surrogate model for the response bound is constructed,namely the first-level Kriging *** training samples required for this surrogate model are obtained by establishing the second-level Kriging *** second-level Kriging model is established to describe the structural responses at particular locations relative to the interval variables so as to facilitate the upper and lower bounds of the node response required by the first-level Kriging ***,the accuracy and effectiveness of the method are verified through examples.

关键词： Interval field Spatial uncertainty Kriging model Interval finite element analysis Response bounds

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Computer simulation of super-magnetoelastic behavior near critical region of magnetic materials based on phase-field method

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Rare Metals 2023年第8期42卷 2477-2488页

作者： Zhao Zhang Cheng-Chao Hu An-Hang Zhou Yu-Xin Xu Yuan-Yuan Wu Hai-Hua Huang Hou-Bing Huang Jun-Jie Ni Wei Li Wei-Feng Rao School of Materials Science and Engineering Liaocheng UniversityLiaocheng 252059China Advanced Research Institute of Multidisciplinary Science Beijing Institute of TechnologyBeijing 100081China School of Mechanical Engineering Qilu University of Technology(Shandong Academy of Sciences)Jinan 250353China Shandong Institute of Mechanical Design and Research Jinan 250031China

Since the discovery of ferromagnetic morphotropic phase boundary(MPB)in 2010,the connotation and extension of MPB have been becoming more and more *** the last dozen years,much experimental work has been done to design magnetostrictive materials based on the MPB ***,due to the difficulty in direct experimental observations and the complexity of theoretical treatments,the insight into the microstructure property relationships and underlying mechanisms near the ferromagnetic MPB has not been fully ***,we have reviewed our recent computer simulation work about the super-magnetoelastic behavior near the critical region of several typical ***-field modeling and simulation are employed to explore the domain configuration and engineering in single crystals as well as the grain size effect in ***,a general nano-embryonic mechanism for superelasticity is also ***,some future perspectives and challenges are presented to stimulate a deeper consideration of the research paradigm between multiscale modeling and material development.

关键词： Super-magnetoelastic behavior Phase-field simulation Morphotropic phase boundary(MPB)

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Dual nanoprecipitation and nanoscale chemical heterogeneity in a secondary hardening steel for ultrahigh strength and large uniform elongation

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Journal of Materials Science & Technology 2024年第18期185卷 245-258页

作者： Shidong Wang Jinhua Wang Shijie Zhang Daixiu Wei Yang Chen Xuequan Rong Wu Gong Stefanus Harjo Xiaochun Liu Zengbao Jiao Zhigang Yang Gang Sha Chunxu Wang Guang Chen Hao Chen Key Laboratory for Advanced Materials of Ministry of Education School of Materials Science and EngineeringTsinghua UniversityBeijing 100084China School of Materials Science and Engineering/Herbert Gleiter Institute of Nanoscience Nanjing University of Science and TechnologyNanjing 210094China National Key Laboratory of Advanced Casting Technologies MIIT Key Laboratory of Advanced Metallic and Intermetallic Materials TechnologyEngineering Research Center of Materials Behavior and DesignMinistry of EducationNanjing University of Science and TechnologyNanjing 210094China J-PARC Center Japan Atomic Energy AgencyIbaraki 319-1195Japan Institute of Metals College of Materials Science and EngineeringChangsha University of Science&TechnologyChangsha 410114China Department of Mechanical Engineering Research Institute for Advanced ManufacturingThe Hong Kong Polytechnic UniversityHong Kong 999077China Central Iron and Steel Research Institute Beijing 100081China

Nanoprecipitates and nanoscale retained austenite(RA)with suitable stability play crucial roles in deter-mining the yield strength(YS)and ductility of ultrahigh strength steels(UHSSs).However,owing to the kinetics incompatibility between nanoprecipitation and austenite reversion,it is highly challenging to si-multaneously introduce high-density nanoprecipitates and optimized RA in *** this work,through the combination of austenite reversion treatment(ART)and subsequent flash austenitizing(FA),nanoscale chemical heterogeneity was successfully introduced into a low-cost UHSS prior to the aging *** chemical heterogeneity involved the enrichment of Mn and Ni in the austenite *** resulting UHSS exhibited dual-nanoprecipitation of Ni(Al,Mn)and(Mo,Cr)_(2)C and nanoscale austenite stabilized via Mn and Ni *** hard martensitic matrix strengthened by high-density dual-nanoprecipitates con-strains the plastic deformation of soft RA with a relatively low fraction of-15%,and the presence of relatively stable nanoscale RA with adequate Mn and Ni enrichment leads to a marginal loss in YS but keeps a persistent transformation-induced plasticity(TRIP)*** a result,the newly-developed UHSS exhibits an ultrahigh YS of-1.7 GPa,an ultimate tensile strength(UTS)of-1.8 GPa,a large uniform elongation(UE)of-8.5%,and a total elongation(TE)of-13%.The strategy of presetting chemical heterogeneity to introduce proper metastable phases before aging can be extended to other UHSSs and precipitation-hardened alloys.

关键词： Ultrahigh strength steels Dual-nanoprecipitation Austenite stability TRIP effect Phase transformation

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Learning-based tracking control of AUV:Mixed policy improvement and game-based disturbance rejection

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CAAI Transactions on Intelligence Technology 2025年第2期10卷 510-528页

作者： Jun Ye Hongbo Gao Manjiang Hu Yougang Bian Qingjia Cui Xiaohui Qin Rongjun Ding State Key Laboratory of Advanced Design and Manufacturing Technology for Vehicle College of Mechanical and Vehicle EngineeringHunan UniversityChangshaChina School of Information Science and Technology and Institute of Advanced TechnologyUniversity of Science and Technology of ChinaHefeiChina Nanyang Technological University SingaporeSingapore Wuxi Intelligent Control Research Institute of Hunan University Hunan UniversityWuxiChina

A mixed adaptive dynamic programming(ADP)scheme based on zero-sum game theory is developed to address optimal control problems of autonomous underwater vehicle(AUV)systems subject to disturbances and safe *** combining prior dynamic knowledge and actual sampled data,the proposed approach effectively mitigates the defect caused by the inaccurate dynamic model and significantly improves the training speed of the ADP ***,the dataset is enriched with sufficient reference data collected based on a nominal model without considering modelling ***,the control object interacts with the real environment and continuously gathers adequate sampled data in the *** comprehensively leverage the advantages of model-based and model-free methods during training,an adaptive tuning factor is introduced based on the dataset that possesses model-referenced information and conforms to the distribution of the real-world environment,which balances the influence of model-based control law and data-driven policy gradient on the direction of policy *** a result,the proposed approach accelerates the learning speed compared to data-driven methods,concurrently also enhancing the tracking performance in comparison to model-based control ***,the optimal control problem under disturbances is formulated as a zero-sum game,and the actor-critic-disturbance framework is introduced to approximate the optimal control input,cost function,and disturbance policy,***,the convergence property of the proposed algorithm based on the value iteration method is ***,an example of AUV path following based on the improved line-of-sight guidance is presented to demonstrate the effectiveness of the proposed method.

关键词： adaptive dynamic programming autonomous underwater vehicle game theory optimal control reinforcement learning

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Flexible Wearable Joint Motion Sensor Based On Multi-Wire Displacement

Flexible Wearable Joint Motion Sensor Based On Multi-Wire Di...

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IEEE International Conference on Soft Robotics (RoboSoft)

作者： Youngjoon Baek Yong-Lae Park Department of Mechanical Engineering The Institute of Advanced Machines and Design the Institute of Engineering Research Seoul National University Seoul Korea

The kinematic monitoring of human joint movements is beneficial in various applications, including biomechanics, rehabilitation, and wearable robotics. For consistent monitoring of human motions in different situations, a portable monitoring system with a compact form factor would be highly useful. However, most existing devices are susceptible to external disturbances or require a tedious and repetitive calibration process. In this paper, we propose a flexible and compact joint angle detection mechanism that allows for the estimation of the full configuration of the target joint, as well as the measurement of a flexion angle. The proposed approach incorporates a simple geometry, whereby the configuration of a two-dimensional rigid body can be determined by the lengths of three wires. A stand-alone device for the analysis of knee flexion based on the proposed mechanism is demonstrated and experimentally evaluated considering the in-plane assumption and the out-of-plane errors. The proposed sensor system estimates the flexion angle with root-mean-square errors of 3.96°, 4.23°, and 7.46° for an in-plane, a translated, and a rotated configurations, respectively. Finally the sensor was mounted on the knee of a human subject and estimated the knee flexion angle during walking.

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Cosolvent electrolyte chemistries for high-voltage potassium-ion battery

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National Science Review 2024年第11期11卷 172-182页

作者： Mengkang Shen Zhongqin Dai Ling Fan Hongwei Fu Yuanhui Geng Jie Guan Fanfei Sun Apparao M.Rao Jiang Zhou Bingan Lu School of Physics and Electronics Hunan University School of Physical Science and Technology Shanghai Tech University Shanghai Synchrotron Radiation Facility Shanghai Advanced Research Institute Chinese Academy of Sciences Shanghai Institute of Applied Physics Chinese Academy of Sciences Department of Physics and Astronomy Clemson Nanomaterials Institute Clemson University School of Materials Science and Engineering Central South University State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body Hunan University

The poor oxidation resistance of traditional electrolytes has hampered the development of high-voltage potassium-ion battery technology. Here, we present a cosolvent electrolyte design strategy to overcome the high-voltage limitations of potassium-ion electrolyte chemistries. The cosolvent electrolyte breaks the dissolution limitation of the salt through ion–dipole interactions, significantly enlarging the anion-rich solvation clusters, as verified by the in situ synchrotron-based wide-angle X-ray scattering ***, the large anion-rich solvation clusters also facilitate the formation of an effective electrode–electrolyte interphase, thereby enhancing compatibility with high-voltage electrodes. The cosolvent electrolyte enables K||Prussian blue cells (2–4.5 V) to operate for >700 cycles with a capacity retention of 91.9%. Our cosolvent electrolyte design strategy paves new avenues for the development of high-voltage potassium-ion batteries and beyond.

关键词： potassium-ion battery cosolvent electrolyte high-voltage anion-rich solvation large solvation clusters

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Slip system analysis of magnesium alloy AZ31B in warm compression by Visco-Plastic Self-Consistent simulation

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Keikinzoku/Journal of Japan institute of Light Metals 2024年第2期74卷 73-82页

作者： Matsuoka, Yusuke Bian, Mingzhe Tsukada, Yuhki Koyama, Toshiyuki Chino, Yasumasa Department of Materials Design Innovation Engineering Graduate School of Engineering Nagoya University Furo-Cho Chikusa-Ku Aichi Nagoya-shi464-8603 Japan Department of Materials Design Innovation Engineering Graduate School of Engineering Nagoya University Aichi Nagoya-shi Japan Multi-Material Research Institute National Institute of Advanced Industrial Science and Technology（AIST） Aichi Nagoya-shi Japan

The active deformation mode (slip systems and twinning) of extruded AZ31B alloy (Mg-3Al-1Zn, mass%) during compression at RT, 100°C and 150°C was investigated by visco-plastic self-consistent (VPSC) simulation. Compression tests were first performed to obtain compression curve of AZ31B. The VPSC model was fitted to the compression curves to estimate the Voce hardening parameters which are required for the VPSC simulation. In the case of compression along the extrusion direction, work-hardening occurred rapidly with the transition of dominant deformation modes at all temperatures. In the case of compression to the other directions, basalslip was dominant throughout the deformation at all compression temperatures. In addition, prismaticslip and tensile twin were active in the early stage of deformation, and pyramidalslip became active in the later stage of deformation. Pyramidalslip became more active with increasing temperature from RT to 100°C, whereas basaland prismaticslips became more active with increasing temperature from 100°C to 150°C. These different trends in the change of the active slip system with increasing temperature can be attributed to the CRSS maximum of the pyramidalslip located around 100°C. © 2024 Japan institute of Light Metals. All rights reserved.

关键词： Magnesium alloys

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Development of Ni-doped Co3O4 oxygen evolution catalysts for anion exchange membrane water electrolysis

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International Journal of Hydrogen Energy 2024年 72卷 677-686页

作者： Murugesan, Ramesh Aravind Chandar Nagamuthu Raja, Krishna Devi, Nitika Lin, Hung-Tse Huang, Cheng-Che Jiang, Xin-Yu Li, Yuan-Yao Arthanareeswaran, Gangasalam Ponvijayakanthan, L. Jaiswal, Neeraj K. Chen, Yong-Song Department of Physics School of Advanced Sciences Vellore Institute of Technology Vellore632014 India Department of Mechanical Engineering and Advanced Institute of Manufacturing with High-tech Innovations National Chung Cheng University Chiayi County 621301 Taiwan Department of Chemical Engineering and Advanced Institute of Manufacturing with High-tech Innovations National Chung Cheng University Chiayi County 621301 Taiwan Membrane Research Laboratory Department of Chemical Engineering National Institute of Technology Tiruchirappalli620 015 India 2-D Materials Research Laboratory Discipline of Physics PDPM Indian Institute of Information Technology Design and Manufacturing M.P. 482005 Jabalpur India

This study investigates nickel-doped cobalt oxide (Ni-doped Co3O4) nanoparticles as catalysts for the oxygen evolution reaction (OER) in anion exchange membrane water electrolyzers (AEMWEs). Through various characterization techniques, Ni0.45Co2.55O4 was identified as exhibiting superior OER activity compared to pristine Co3O4 and other Ni-doped compositions, offering reduced overpotential and higher current density. Density functional theory (DFT) calculations provided mechanistic insights. Evaluation in an AEMWE single-cell setup confirmed Ni0.45Co2.55O4 stability and efficiency for hydrogen production. The study underscores the importance of transitioning to renewable sources for hydrogen production and highlights the role of AEMWEs with non-noble metal catalysts in reducing costs. Moreover, it emphasizes the critical influence of the OER on AEMWE performance. Overall, the research demonstrates the potential of Ni-doped Co3O4 nanoparticles as effective catalysts for sustainable hydrogen production, aligning with the goal of achieving 2050 net-zero emissions. © 2024 Hydrogen Energy Publications LLC

关键词： Cobalt compounds

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LQR-based control strategy for improving human-robot companionship and natural obstacle avoidance

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Biomimetic Intelligence & Robotics 2024年第4期4卷 38-47页

作者： Zefan Su Hanchen Yao jianwei Peng Zhelin Liao Zengwei Wang Hui Yu Houde Dai Tim C.Lueth School of Advanced Manufacturing Fuzhou UniversityJinjiang 362251China Quanzhou Institute of Equipment Manufacturing Fujian Institute of Research on the Structure of MatterChinese Academy of SciencesJinjiang 362200China Institute of Micro Technology and Medical Device Technology(MIMED) School of Engineering and DesignTechnical University of MunichGarching 85748Germany

In the dynamic and unstructured environment of human-robot symbiosis,companion robots require natural human-robot interaction and autonomous intelligence through multimodal information fu-sion to achieve effective ***,the control precision and coordination of the accompanying actions are not satisfactory in practical *** is primarily attributed to the difficulties in the motion coordination between the accompanying target and the mobile *** paper proposes a companion control strategy based on the Linear Quadratic Regulator(LQR)to enhance the coordination and precision of robot companion *** method enables the robot to adapt to sudden changes in the companion target's ***,the robot could smoothly avoid obstacles during the companion ***,a human-robot companion interaction model based on nonholonomic constraints is developed to determine the relative position and orientation between the robot and the companion ***,an LQR-based companion controller incorporating behavioral dynamics is introduced to simultaneously avoid obstacles and track the companion target's direction and ***,various simulations and real-world human-robot companion experiments are conducted to regulate the relative position,orientation,and velocity between the target object and the robot *** results demonstrate the superiority of this approach over conventional control algorithms in terms of control distance and directional errors throughout system *** proposed LQR-based control strategy ensures coordinated and consistent motion with target persons in social companion scenarios.

关键词： Human-robot interaction Linearquadratic regulator Human-accompanying robots Behavioral dynamics

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