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Active and switchable thermal control

Science China(Physics,Mechanics & Astronomy) 2022年第11期65卷 80-81页

作者： Chenhan Liu Yunfei Chen Micro-and Nano-scale Thermal Measurement and Thermal Management Laboratory School of Energy and Mechanical EngineeringNanjing Normal UniversityNanjing210046China Jiangsu Key Laboratory for Numerical Simulation of Large-Scale Complex Systems Nanjing Normal UniversityNanjing210046China Jiangsu Key Laboratory for Design and Manufacture of Micro-Nano Biomedical Instruments School of Mechanical EngineeringSoutheast UniversityNanjing211100China

In the past century, actively controlling electron transport has led to unprecedented advances in the digital world. Controlling phonon(i.e., thermal) transport like electron transport is a current topic of interest. To realize active and switchable thermal control(Figure 1), numerous studies have been conducted recently due to the emerging challenges in the fields of thermal management, heating and refrigeration.

关键词： thermal transport Figure

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Experimental investigation of transfer of ptfe on bearing steel 6th

Experimental investigation of transfer of ptfe on bearing st...

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6th International Conference on Building Materials and Construction, ICBMC 2021, Nanotechnology and Nanomaterials in Energy, ICNNE 2021, and Energy engineering and Smart Materials, ICEESM 2021

作者： Chaihad, Sid Tuchinda, Karuna Mechanical Engineering Simulation and Design Mechanical and Automotive Engineering The Sirindhorn International Thai-German Graduate School of Engineering King Mongkut’s University of Technology North Bangkok Thailand

ISBN: (纸本)9783035718928

Polytetrafluoroethylene (PTFE) lubricant is commonly applied for dry contact due to its low friction properties. However, low strength properties can lead to short service-life due to high wear rate, especially under high contact load. The method to add PTFE into a solid contact during operation as a transfer layer has been one of the major attempts in this field. This study aims to investigate the influence of operating parameters, i.e., revolution cycle, sliding speed and applied load, on coverage area of transfer PTFE on the bearing steel (AISI 52100) disc. The experiments were performed on the modified pin-on-disc apparatus using a unidirectional ground disc. The areas with disc grinding direction parallel (parallel morphology) and perpendicular (perpendicular morphology) to the pin sliding direction were both examined. The ascending of transfer coverage area with an increasing revolution cycle within the first 1000 cycle was observed on the area with a sliding direction perpendicular to the disc grinding direction while the descending of transfer coverage area was found on the parallel case. The further increase in the revolution cycle led to only a small change in the transfer coverage area. With more revolution cycles, the pin wear rate increased as a decrease in transfer coverage area formed on the counter-face. Research suggested that the amount of transfer coverage area decreased with increasing sliding speed. However, it could be increased by increasing the applied load. © 2021 Trans Tech Publications Ltd, Switzerland.

关键词： Morphology

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Development of Machine Learning-Based Assessment System for Laparoscopic Surgical Skills Using Motion-Capture

Development of Machine Learning-Based Assessment System for ...

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2024 IEEE/SICE International Symposium on System Integration, SII 2024

作者： Ebina, Koki Abe, Takashige Yan, Lingbo Hotta, Kiyohiko Highuchi, Madoka Iwahara, Naoya Furumido, Jun Kon, Masafumi Murai, Sachiyo Kurashima, Yo Komizunai, Shunsuke Tsujita, Teppei Sase, Kazuya Chen, Xiaoshuai Senoo, Taku Shinohara, Nobuo Konno, Atsushi Graduate School of Information Science and Technology Hokkaido University Sapporo Japan Hokkaido University Faculty of Medicine Department of Renal and Genitourinary Surgery Sapporo Japan Hokkaido University Clinical Simulation Center Faculty of Medicine Sapporo Japan Kagawa University Faculty of Engineering and Design Takamatsu Japan National Defense Academy of Japan Department of Mechanical Engineering Yokosuka Japan Tohoku Gakuin University Department of Mechanical Engineering and Intelligent Systems Sendai Japan Graduate School of Science and Technology Hirosaki University Hirosaki Japan

ISBN: (纸本)9798350312072

Laparoscopic surgery is a widely used surgical technique, on the other hand, its high degree of difficulty makes it difficult for beginners to learn the technique efficiently. In addition, recent working hour restrictions and shortages of surgeons have resulted in insufficient training time, and establishing the efficiently training methods is becoming urgent needs. Therefore, to promote the skill proficiency of novice surgeons, machine learning-based assessment system for laparo-scopic surgical skills was developed. A measurement system with a simple configuration was introduced so that trainees can easily use it alone. Alternatively, the indices related to the opening ratio and the rotation angle of surgical instruments, which were measured in the authors' previous study were no longer available. Therefore, comparative experiments were conducted to verify the effect of the lack of indices related to these data on the accuracy of skill evaluation. Based on the measurement data of 104 wet lab trainings measured in the previous study, a machine learning model that evaluates surgeon's skill at 3 levels based on the number of surgical experiences, and global operative assessment of laparoscopic skills (GOALS) which is a type of surgical skill evaluation index were established. By using the explainable AI method, this system can present the skill evaluation result including its basis to the trainee. Since the developed system can be easily operated by a GUI-based program, trainees can confirm the quantitative evaluation result on-site immediately after the training. © 2024 IEEE.

关键词： Laparoscopy

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design,Characterization and Optimization of Multi-directional Bending Pneumatic Artificial Muscles

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Journal of Bionic engineering 2021年第6期18卷 1358-1368页

作者： Wei Xiao Dean Hu Weixiong Chen Gang Yang Xu Han State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body College of Mechanical and Vehicle EngineeringHunan UniversityChangsha410082People’s Republic of China Key Laboratory of Advanced Design and Simulation Techniques for Special Equipment Ministry of EducationHunan UniversityChangsha410082People’s Republic of China School of Mechanical Engineering Hebei University of TechnologyTianjin300401People’s Republic of China

Bending Pneumatic Artificial Muscles(PAMs)are particularly attractive and extensively applied to the soft grasper,snake-like robot,*** extend the application of PAMs,we fabricate a Multi-directional Bending Pneumatic Artificial Muscle(MBPAM)that can bend in eight directions by changing the pressurized *** maximum bending angle and output force are 151°and 0.643 N under the pressure of 100 kPa,***,the Finite Element Model(FEM)is established to further investigate the *** experimental and numerical results demonstrate the nonlinear relationship between the pressure and the bending angle and output ***,the effects of parameters on the performance are studied with the validated *** results reveal that the amplitude of waves and the thickness of the base layer can be ***,multi-objective optimization is performed to improve the bending performance of the *** optimization results indicate that the output force can be increased by 7.8%with the identical bending angle of the initial design,while the bending angle can be improved by 8.6%with the same output ***,the grasp tests demonstrate the grip capability of the soft four-finger gripper and display the application prospect of the MBPAM in soft robots.

关键词： Pneumatic artificial muscle Multi-directional bending Soft robots Parameter optimization

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A New Perspective on Lüders Band Formation in Medium-Mn Steels Based on Lüders-Strain-Rate and Dislocation Evolution

SSRN

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SSRN 2024年

作者： Liu, Chenghuan Hu, Chen Wang, Xiaogang Huang, Mingxin Jiang, Chao Key Laboratory of Advanced Design and Simulation Techniques for Special Equipment Ministry of Education College of Mechanical and Vehicle Engineering Hunan University Changsha410082 China Department of Mechanical Engineering The University of Hong Kong Pokfulam Road Hong Kong State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body China

Propagating Lüders bands with pronounced strain localization are often observed in medium-Mn transformation-induced plasticity (TRIP) steels, which adversely limits the application of such alloys in engineering structures. The present work aims to understand this phenomenon from a dislocation-based perspective, with a focus on the specific role of dislocation multiplication. The material studied is a typical dual-phase medium-Mn steel with a ferrite matrix and a second phase of retained austenite. A warm-rolling process was used as a pre-straining approach to adjust the microstructure of the material, such that materials with two different microstructural states can be obtained: as-received material and pre-strained material. They show distinct differences in initial dislocation density. Stress-controlled rather than conventional strain-controlled tensile testing was adopted, which allowed the Lüders band to develop in an unconstrained manner. In this way, the intrinsic Lüders-strain-rate can be obtained. The results show that the Lüders band-related mechanical parameters, including Lüders strain, Lüders-strain-rate and yield stress drop, all depend on the initial microstructure state and the dislocation evolution process during Lüders band formation. In particular, Lüders-strain-rate is a critical microstructure-sensitive factor. It is closely related to the dislocation multiplication in the formation of Lüders band, which can be characterized and quantified using scanning transmission electron microscope and synchrotron X-ray diffraction. Finally, a quantitative relationship between Lüders-strain-rate and dislocation multiplication rate is established, which allows providing a better understanding of the exceptional Lüders band phenomenon in medium-Mn steels. © 2024, The Authors. All rights reserved.

关键词： Strain rate

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An Efficient Thermoelastic Topology Optimization Method for Large-Scale Structures Based on Parallel Computing

SSRN

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SSRN 2024年

作者： Rong, Xuanpei Zheng, Jing Jiang, Chao Luo, Zhen Key Laboratory of Advanced Design and Simulation Techniques for Special Equipment School of Mechanical and Vehicle Engineering Hunan University Hunan Province Changsha410082 China School of Mechanical and Mechatronic Engineering University of Technology Sydney 15 Broadway UltimoNSW2007 Australia State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body China

The optimization of complex structures considering thermal-mechanical coupling is a critical issue in current equipment design. The integration of large-scale thermoelastic topology optimization within the parallel computing framework represents a pivotal advancement in structural engineering. Large-scale thermoelastic topology optimization has historically confronted two main difficulties: Firstly, the conflicts among multi-field performance criteria under large-scale topology variables lead to issues such as blurring in low-density regions, constraint failures, and instability in the optimization process. Secondly, the computational cost of performing finite element calculations and optimization in a multi-physics environment is prohibitively high. Building on these considerations, this paper develops an effective approach for large-scale thermo-mechanical coupled topology optimization, utilizing parallel computing to enhance efficiency. In addressing the issue of non-convergence in the distribution of thermal and elastic materials within low-density regions under thermoelastic conditions, a modified thermoelastic material interpolation model is proposed. Subsequently, the compliance sensitivity with respect to the topological variables is obtained from the derived explicit expressions and the iterative topological variables are renewed. An assembly-free matrix parallel strategy is introduced to substantially lower the computational expenses associated with thermo-mechanical coupling finite element simulation models and topology optimization processes. This strategy utilizes an enhanced Preconditioned Conjugate Gradient (PCG) iterative algorithm and a stepwise computation approach, effectively diminishing the optimization's computational cost. Finally, the proposed thermoelastic topology optimization method for complex thermos-mechanical coupled structures is implemented through co-programming of MATLAB, CUDA and ABAQUS, and a series of representative examples are

关键词： MATLAB

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Current trends and developments of product modularisation – A bibliometric analysis 23

Current trends and developments of product modularisation –...

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23rd International Conference on engineering design, ICED 2021

作者： Mertens, Kai G. Rennpferdt, Christoph Greve, Erik Krause, Dieter Meyer, Matthias Hamburg University of Technology Institute of Management Accounting and Simulation Germany Hamburg University of Technology Institute of Product Development and Mechanical Engineering Design Germany

Product modularisation continuously draws attention of scholars and practitioners since it supports organizations and industries to sustain in high product and service variety at reasonable costs and greater flexibility. This paper aims at revealing current trends and developments in the field of product modularisation by identifying the intellectual structure using a bibliometric review. Our sample accrues 1,366 publications from 2016 up to 2020 across disciplines while using bibliometric coupling composes a network. Analysing the network on similarities, we can not only find clusters of servitisation, closed-loop supply chains, and platform collaboration, because we also identify three trends of digital innovation, sustainability, and platform eco-systems. An analysis of authors currently indicates less integrated communities, which do not entirely refer to each other despite the similarity in their research. Collectively, the study suggests a timely update of current scholar activities and discussions in the field of product modularisation. © ICED *** right reserved.

关键词： Sustainable development

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Quantum combinatorial design 23

Quantum combinatorial design

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23rd International Conference on engineering design, ICED 2021

作者： Gopsill, James Johns, Guy Hicks, Ben Design Manufacturing Futures Lab School of Civil Aerospace and Mechanical Engineering University of Bristol United Kingdom Centre for Modelling and Simulation Bristol United Kingdom

Combinatorial design such as configuration design, design optioneering, component selection, and generative design, is common across engineering. Generating solutions for a combinatorial design task often involves the application of classical computing solvers that can either map or navigate design spaces. However, it has been observed that classical computing resource power-law scales with many design space models. This observation suggests classical computing may not be capable of modelling our future design space needs. To meet future design space modelling needs, this paper examines quantum computing and the characteristics that enables its resources to scale polynomially with design space size. The paper then continues to present a combinatorial design problem that is subsequently represented, constrained and solved by quantum computing. The results of which are the derivation of an initial set of circuits that represent design space constraints. The study shows the game-changing possibilities of quantum computing as an engineering design tool and is the start of an exciting new journey for design research. © ICED *** right reserved.

关键词： Quantum computers

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Demystifying digital X 23

Demystifying digital X

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23rd International Conference on engineering design, ICED 2021

作者： Cox, Chris Gopsill, James Hicks, Ben Design Manufacturing Futures Lab School of Civil Aerospace and Mechanical Engineering University of Bristol United Kingdom Centre for Modelling and Simulation Bristol United Kingdom

The rapid pace of development in Digital engineering has led to an explosion of ideas and new practice in how it can support engineering design and Manufacture. You may have heard of the terms Digital Transformation, Digital Twin, Digital Thread, Digital Tapestry and Digital Footprint amongst many other forms of ``Digital X'' but how have these come about and how do they come together to provide the landscape of what Digitalisation has to offer? In this paper, we analyse the emergence, definition, use and co-occurrence of ``Digital X'' terminology from an academic dataset of 19,627 papers curated from Scopus. The results reveal that these terms are being used without being fully contextualised in terms of a hierarchy or equivalent to effectively articulate the Digital landscape. Through this analysis, an emerging ``Digital X'' framework is proposed, with evidence given to support suggested links, and knowledge gaps highlighted for further investigation. Once this framework is complete, a rich lexicon describing the Digital Landscape will pave the way for the future in Digital engineering. © ICED *** right reserved.

关键词： Co-word analysis Communication Digital / Digitised engineering value chains Digital transformation Ontologies

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Priority Evaluation of Civil Aircraft design Optimization Based on Competitiveness Model

Priority Evaluation of Civil Aircraft Design Optimization Ba...

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mechanical engineering and Aerospace engineering (MEAE), Asia Conference on

作者： Jianyang Zhang Yunpeng Ding State Key Laboratory of Airliner Integration Technology and Flight Simulation Shanghai Aircraft Design & Research Institute Shanghai China Quality Management Department Shanghai Electro-Mechanical Engineering Institute Shanghai China

ISBN: (数字)9798350352252

ISBN: (纸本)9798350352269

This article proposed and constructed a competitiveness evaluation model based on stakeholder satisfaction as the evaluation criterion for single-aisle passenger aircraft in service. During competitiveness modeling, the analytic hierarchy process method was applied to determine the weights of stakeholders and the attributes they concern. And the attribute parameters were normalized in a sigmoid function to make the evaluation more reasonable. Three pending optimization projects were evaluated and prioritized by the competitiveness model. The drag reduction optimization project which could reduce the direct operating cost without negative impact on aircraft attributes is the most effective way to enhance the overall competitiveness.

关键词： Atmospheric modeling Evaluation models Production Aircraft manufacture Stakeholders Aircraft Aircraft propulsion mechanical engineering Optimization design optimization

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