检索结果-南通市图书馆

Pseudo-rigid-body Model for Corrugated Cantilever Beam Used in Compliant Mechanisms

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Mechanical Engineering 2014年第1期27卷 122-129页

作者： wang nianfeng LIANG Xiaohe ZHANG Xianmin Guangdong Province Key Laboratory of Precision Equipment and Manufacturing Technology South China University of Technology State Key Laboratory of Mechanical System and Vibration Shanghai Jiao Tong University

Common compliant joints generally have limited range of motion, reduced fatigue life and high stress concentration. To overcome these shortcomings, periodically corrugated cantilever beam is applied to design compliant joints. Basic corrugated beam unit is modeled by using pseudo-rigid-body method. The trajectory and deformation behavior of periodically corrugated cantilever beam are estimated by the transformation of coordinate and superposition of the deformation of corrugated beam units. Finite element analysis（FEA） is carried out on corrugated cantilever beam to estimate the accuracy of the pseudo-rigid-body model. Results show that the kinetostatic behaviors obtained by this method, which has a relative error less than 6%, has good applicability and corrugated cantilever beam has the characteristics of a large range of motion and high mechanical strength. The corrugated cantilever beam is then applied to design a flexible rotational joint to obtain a larger angle output. The paper proposes a pseudo-rigid-body model for corrugated cantilever beam and designed a flexible rotational joint with large angle output.

关键词： corrugated beam pseudo rigid body method compliant mechanisms

Spring-Joint Method for Topology Optimization of Planar Passive Compliant Mechanisms

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Mechanical Engineering 2013年第6期26卷 1063-1072页

作者： JIN Mohui ZHANG Xianmin ZHU Benliang wang nianfeng Guangdong Provincial Key Laboratory of Precision Equipment and Manufacturing Technology South China University of Technology

There is seldom approach developed for the initial topology design of flexure-based compliant mechanisms. The most commonly-used approaches, which start with an existing rigid-body mechanism, do not consider the performances between different topologies. Moreover, they rely heavily on the rigid-body topology, therefore limit the diversity of compliant mechanisms topology. To obtain the optimal initial topology of such mechanisms directly from problem specifications without referencing to the existing mechanism topologies, a spring-joint method is presented for a restricted class of the serial passive flexure-based compliant mechanisms, which are the building blocks of parallel compliant mechanisms. The topology of the compliant mechanisms is represented by a serial spring-joint mechanism（SSJM） that is a traditional rigid-body mechanism with a torsional spring acting on each joint, and is described by position vectors of the spring-joints. A simplified compliance matrix, determined by the position vectors, is used to characterize the tip of the SSJM kinematically, and is optimized to ensure the desired freedoms of the compliant mechanisms during optimization. The topology optimization problem is formulated as finding out the optimal position of the spring-joints in a blank design domain with an objective function derived from the simplified compliance matrix. In design examples, syntheses of the compliant mechanisms with both single freedom and two decoupled freedoms are presented to illustrate the proposed method. The proposed method provides a new way for the initial design of flexure-based compliant mechanisms.

关键词： compliant mechanism synthesis topology optimization spring-joint

Advances in dielectric elastomer actuation technology

在线全文

学校读者我要写书评

暂无评论

Science China(Technological Sciences) 2018年第10期61卷 1512-1527页

作者： wang nianfeng CUI ChaoYu GUO Hao CHEN BiCheng ZHANG XianMin Guangdong Provincial Key Laboratory of Precision Equipment and Manufacturing Technology South China University of Technology

Dielectric elastomer actuators(DEAs) have attracted much interest over the past decades due to the inherent flexibility, large strain, high efficiency, high energy density, and fast response of the material, which are known as one of the most promising candidates for artificial muscle. In this paper, we first introduce the actuation principle and electromechanical modeling approaches of dielectric elastomers(DEs). Then, the performance of different DEs material and existing compliant electrodes that are widely utilized for DEAs are presented. We also highlight the compatibility of DEs, which is suitable for a variety of actuator designs and applications. Lastly, we summarize the challenges and future development in terms of electromechanical modeling, improvement of materials including compliant electrodes and dielectric elastomer, designs and applications of novel dielectric elastomer actuators.

关键词：弹性体绝缘技术进展应用程序致动器材料力密度快反应

Multi-objective Topology Optimization of Thermo-mechanical Compliant Mechanisms

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Mechanical Engineering 2011年第6期24卷 1123-1129页

作者： LI Dongmei ZHANG Xianmin GUAN Yisheng ZHANG Hong wang nianfeng School of Mechanical andAutomotive Engineering South China University of Technology Guangzhou 510640 China Guangdong Polytechnic Normal University Guangzhou 510665 China School of Computing Science University of Alberta Edmonton AB Canada

The material characteristics of a structure will change with temperature variation,and will induce stress within the structure.Currently,the optimal design for the topology of compliant mechanisms is mainly performed in single physical field.However,when compliant mechanisms work in high temperature environments,their displacement outputs are generated not only by mechanical load,but also by the temperature variation which may become the prominent factor.Therefore,the influence of temperature must be considered in the design.In this paper,a novel optimization method for multi-objective topology of thermo-mechanical compliant mechanisms is presented.First,the thermal field is analyzed with finite-element method,where the thermal strain is taken into account in the constitutive relation,and the equivalent nodal thermal load is derived with the principle of virtual work.Then the thermal load is converted into physical loads in elastic field,and the control equation of the thermo-mechanical compliant mechanism is obtained.Second,the mathematical model of the multi-objective topology optimization is built by incorporating both the flexibility and stiffness.Meanwhile,the coupling sensitivity function and the sensitivity analysis equations of thermal steady-state response are derived.Finally,optimality criteria algorithm is employed to obtain numerical solution of the multi-objective topology optimization.Numerical examples show that the compliant mechanisms have better performance and are more applicable if the temperature effect is taken into account in the design process.The presented modeling and analysis methods provide a new idea and an effective approach to topology optimization of compliant mechanisms in electrothermic coupling field and multiphysics fields.

关键词： compliant mechanisms topology optimization thermo-mechanical coupling multi-objective coupling sensitivity

面向工程教育认证的物联网工程专业人才培养方案构建——以A校物联网工程专业为例

在线全文

学校读者我要写书评

暂无评论

计算机应用文摘 2024年第8期40卷 1-4页

作者：李晨王龙刚侯小静石念峰洛阳理工学院计算机与信息工程学院河南洛阳471023

为进一步探索新工科背景下物联网工程专业的人才培养模式,文章将以工程教育认证标准及计算机类专业补充标准为依据,并结合洛阳理工学院物联网工程专业的特色,从人才培养目标、毕业要求分析及指标点分解、课程体系设置等方面构建物联网... 详细信息

为进一步探索新工科背景下物联网工程专业的人才培养模式,文章将以工程教育认证标准及计算机类专业补充标准为依据,并结合洛阳理工学院物联网工程专业的特色,从人才培养目标、毕业要求分析及指标点分解、课程体系设置等方面构建物联网工程专业的人才培养方案。这个方案将体现出重基础、强实践的学生培养路线,同时在专业建设方面锻强提质,旨在为服务区域经济提供智力支持。

关键词：工程教育认证物联网工程人才培养课程体系设置

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

笔迹鉴定标准比较研究

中国司法鉴定 2024年第1期 99-106页

作者：张宇宽施少培王雅晨孙年峰华东政法大学刑事法学院上海200042 司法鉴定科学研究院上海市司法鉴定专业技术服务平台司法部司法鉴定重点实验室上海200063

近年来,随着我国法庭科学的迅猛发展,国家更新了一批鉴定标准和技术规范,但由于我国司法体制的独特性,相关标准在适用时依然会造成困惑。立足标准的适用性并运用比较法的思维方式,通过对欧洲和美国笔迹鉴定相关标准分别进行介绍,并进一... 详细信息

近年来,随着我国法庭科学的迅猛发展,国家更新了一批鉴定标准和技术规范,但由于我国司法体制的独特性,相关标准在适用时依然会造成困惑。立足标准的适用性并运用比较法的思维方式,通过对欧洲和美国笔迹鉴定相关标准分别进行介绍,并进一步与我国笔迹鉴定标准进行比较研究,发现不同标准制定组织所制定的鉴定标准在基本架构、标准内容、结论表述方式等方面均有不同。针对上述比较发现的不同,以小窥大,分析差异的产生原因,同时注意到国内笔迹鉴定标准在内容和体系上亦有不同,对此进行分析并结合我国笔迹鉴定现状提出建议,以期为笔迹鉴定实践及未来标准修订带来启示。

关键词：笔迹鉴定标准比较研究

Engineering upconverting core–shell nano-probe for spectral responsive fluid velocimetry

在线全文

学校读者我要写书评

暂无评论

Nano Research 2023年第1期16卷 1212-1219页

作者： Hai Huang Shaoxiong wang Runyu Chen nianfeng Zhang Hu-Rong Yao Yuanhui Zheng Feng Huang Daqin Chen College of Physics and Energy Fujian Normal UniversityFujian Provincial Key Laboratory of Quantum Manipulation and New Energy MaterialsFuzhou 350117China Fujian Science&Technology Innovation Laboratory for Optoelectronic Information Fuzhou 350116China Fujian Provincial Collaborative Innovation Center for Advanced High-Field Superconducting Materials and Engineering Fuzhou 350117China Fujian Provincial Engineering Technology Research Center of Solar Energy Conversion and Energy Storage Fuzhou 350117China College of Chemistry Fuzhou UniversityFuzhou 350116China

Particle velocimetry based on the temporal feature of upconversion luminescent nanocrystals is a newly-raising fluid velocimetry.Exploiting the availability to low flow rate fluid and exempting redundance external calibration(achieving once calibration for all)are highly expected and challenging.Herein,an engineered core–shell nano-probe,NaYF4:Yb/Ho/Ce@NaGdF4,was proposed,in which the Ce3+ions were utilized to manipulate the upconversion dynamic of Ho3+.Through optimization,a superior sensitive against low-speed flow is achieved,and the external calibrations before each operation can be avoided.Application demonstrations were conducted on a fluid circulation system with controllable flow rate.The fluid velocity was monitored successfully,no matter it is permanent,or cyclically variating(imitating the in vivo arterial blood).Moreover,this velocimetric route is competent in spatial scanning for handling the spatially inhomogeneous velocity field.Such sensing nanomaterial and fluid velocimetric method exhibit promising application potential in human blood velocimetry,industrial control,or environmental monitoring.

关键词： core-shell nanocrystals upconversion temporal dynamic fluid velocimetry

Fabrication of ion doped WO_3 photocatalysts through bulk and surface doping

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2015年第9期27卷 76-82页

作者： Xiaoying wang Laixue Pang Xiuying Hu nianfeng Han School of Materials Science and Engineering Shandong Jiaotong University

Na＋doped WO3 nanowire photocatalysts were prepared by using post-treatment（surface doping） and in situ（bulk doping） doping methods. Photocatalytic degradation of Methyl Blue was tested under visible light irradiation, the results showed that 1 wt.% Na＋bulk-doped WO3 performed better, with higher photoactivity than surface-doped WO3. Photoelectrochemical characterization revealed the differences in the photocatalytic process for surface doping and bulk doping. Uniform bulk doping could generate more electron–hole pairs, while minimizing the chance of electron–hole recombination. Some bulk properties such as the bandgap, Fermi level and band position could also be adjusted by bulk doping, but not by surface doping.

关键词： WO3 Bulk doping Surface doping Photocatalysis Photoelectrochemistry

Design and Myoelectric Control of an Anthropomorphic Prosthetic Hand

在线全文

学校读者我要写书评

暂无评论

Journal of Bionic Engineering 2017年第1期14卷 47-59页

作者： nianfeng wang Kunyi Lao Xianmin Zhang Guangdong Province Key Laboratory of Precision Equipment and Manufacturing Technology South China University of Technology Guangzhou 510640 China

This paper presents an anthropomorphic prosthetic hand using flexure hinges, which is controlled by the surface electromyography （sEMG） signals from 2 electrodes only. The prosthetic hand has compact structure with 5 fingers and 4 Degree of Freedoms （DoFs） driven by 4 independent actuators. Helical springs are used as elastic joints and the joints of each finger are coupled by tendons. The myoelectric control system which can classify 8 prehensile hand gestures is built. Pattern recognition is employed where Mean Absolute Value （MAV）, Variance （VAR）, the fourth-order Autoregressive （AR） coefficient and Sample Entropy （SE） are chosen as the optimal feature set and Linear Discriminant Analysis （LDA） is utilized to reduce the dimension. A decision of hand gestures is generated by LDA classifier after the current projected feature set and the previous one are ＂pre-smoothed＂, and then the final decision is obtained when the current decision and previous decisions are ＂post-smoothed＂ from the decisions flow. The prosthetic hand can perform prehensile postures for activities of daily living and carry objects under the control of EMG signals.

关键词： electromyography anthropomorphic prosthetic hand myoelectric control pattern recognition prehensile gestures