检索结果-南通市图书馆

The Boundary Element Method for Ordinary state-Based Peridynamics

Computer Modeling in engineering & sciences 2024年第6期139卷 2807-2834页

作者： Xue Liang Linjuan Wang state key laboratory for turbulence and complex systems Department of Mechanics and Engineering ScienceCollege of EngineeringPeking UniversityBeijing100871China CAPT-HEDPS and IFSA Collaborative Innovation Center of MoECollege of EngineeringPeking UniversityBeijing100871China School of Astronautics Beihang UniversityBeijing100191China

The peridynamics(PD),as a promising nonlocal continuum mechanics theory,shines in solving discontinuous *** to now,various numerical methods,such as the peridynamic mesh-free particlemethod(PD-MPM),peridynamic finite element method(PD-FEM),and peridynamic boundary element method(PD-BEM),have been ***-BEM,in particular,outperforms other methods by eliminating spurious boundary softening,efficiently handling infinite problems,and ensuring high computational ***,the existing PD-BEM is constructed exclusively for bond-based peridynamics(BBPD)with fixed Poisson’s ratio,limiting its applicability to crack propagation problems and scenarios involving infinite or semi-infinite *** this paper,we address these limitations by introducing the boundary element method(BEM)for ordinary state-based peridynamics(OSPD-BEM).Additionally,we present a crack propagationmodel embeddedwithin the framework ofOSPD-BEM to simulate crack *** validate the effectiveness of OSPD-BEM,we conduct four numerical examples:deformation under uniaxial loading,crack initiation in a double-notched specimen,wedge-splitting test,and threepoint bending *** results demonstrate the accuracy and efficiency of OSPD-BEM,highlighting its capability to successfully eliminate spurious boundary softening phenomena under varying Poisson’s ***,OSPDBEMsignificantly reduces computational time and exhibits greater consistencywith experimental results compared to PD-MPM.

关键词： Ordinary state-based peridynamics boundary element method crack propagation fracture toughness

来源：

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

Solar-powered miniature robot for on-site oil spill treatment under magnetic steering

引用

Science china(Technological sciences) 2024年第7期67卷 2164-2175页

作者： WANG Ben CHEN YunRui WANG Yun JI FengTong LI HongYuan NIU ShiChao HAN ZhiWu ZHANG YaBin GUO ZhiGuang College of Chemistry and Environmental engineering Shenzhen UniversityShenzhen 518060China state key laboratory of Featured Metal Materials and Life-cycle Safety for Composite Structures Ministry of Education Key Laboratory of New Processing Technology for Nonferrous Metals and Materialsand School of ResourcesEnvironment and MaterialsGuangxi UniversityNanning 530004China key laboratory for Bionic engineering Ministry of Education Jilin UniversityChangchun 130022China Hubei Collaborative Innovation Centre for Advanced Organic Chemical Materials Ministry of Education Key Laboratory for the Green Preparation and Application of Functional MaterialsHubei UniversityWuhan 430062China Wellcome Trust/Cancer Research UK Gurdon Institute University of CambridgeCambridge CB21QNUK department of Physiology Development and NeuroscienceUniversity of CambridgeCambridge CB21QNUK state key laboratory for turbulence and complex systems Department of Mechanics and Engineering ScienceBeijing Innovation Center for Engineering Science and Advanced TechnologyCollege of EngineeringPeking UniversityBeijing 100871China

Walking on the water surface is an effective method for miniature robots to transport payloads with dramatically decreased interfacial drag. Current aquatic robots reported are generally actuated by a beam of focused light that can trigger asymmetrical deformation, enabling the directional movement through horizontal momentum transfer of photoinduced actuation force to the water. However, the operations are heavily dependent on manual manipulation of the focused light, making the long-term actuation and application of the aquatic robots in vast scenarios challenging. Herein, we developed a kind of water striderinspired robot that can autonomously manage the motion on the water surface under solar irradiation, with their direction steerable by a magnetic field. The motion of this bioinspired robot on the water surface was achieved by the use of a solar cell panel as a driving module to enable propulsive motion based on the conversion of light-electric-mechanical energies. The superhydrophobic design of its leg surfaces enables the aquatic robots with weight-bearing and drag-reducing abilities. With the assistance of magnetic navigation, the bioinspired robot can continuously and controllably locomote to the oily spill floating on the water body and collect them with high efficiency. For further demonstration, the treatment of oil spills in a campus pool with high efficiency has also been achieved. This on-site oil-spill treating strategy, taking advantage of a home-made bioinspired robot actuated by natural sunlight under magnetic steering, shows great potential applications in water-body remediation.

关键词： miniature robot superhydrophobic water strider interfacial friction magnetic actuation

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Modified Chapman–Enskog expansion: A new way to treat divergent series

引用

Chinese Physics B 2017年第8期26卷 1-3页

作者：佘振苏 state key laboratory for turbulence and complex systems and the department of mechanics and Engineenng sciences College of EngineeringPeking UniversityBeijing 100871China

The resolution by Chen and Sun of divergent Chapman-Enskog expansion problem will not only build a unified foundation for non-equilibrium dynamics modeling at all Mach number and Knudsen number, but also shed light to... 详细信息

关键词： Chapman-Enskog expansion non-equilibrium dynamics

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

On the dynamics in a transitional boundary layer

引用

Communications in Nonlinear Science and Numerical Simulation 2001年第3期6卷 111-171页

作者： C. B. LEE and R. LEE department of mechanics and engineering Science/state key laboratory for studies of turbulence and complex systems, peking university, beijing 100871, china department of engineering mechanics, Tsinghua university, beijing 100084, Chi department of mechanics and engineering Science / state key laboratory for studies of turbulence and complex systems Peking University Beijing 100871 China department of engineering mechanics Tsinghua University Beijing 100084 China

A model is presented to describe the dynamic physical processes that occur in a transitional boundary layer flow. The CS-solitons, the closed vortex, the secondary closed vortex and the chain of ring-like vortices are postulated to be the basic flow structures of the transitional boundary layer as well as the turbulent boundary layer. It is argued that the central features of transitional and developed turbulent boundary layer flows can be explained in terms of how the series vortices interact with each other, and with the CS-solitons. The physical process that leads to the regeneration of the new closed vortex along the border of the CS-soliton, as well as the processes of evolution of the vortices to high frequency vortices, is described. The model is supported by the important developments in a number of "kernel" experiments, which illustrate both transitional and developed turbulent boundary layer. An important aspect of the model is that it has been formulated to be consistent with accepted rational mechanics concepts that are known to provide a proper physical description of other flows.

关键词： boundary layer transition dynamic processes onset of turbulence

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Hydrodynamic Analysis and Verification of an Innovative Whale Shark-like Underwater Glider

引用

Journal of Bionic engineering 2020年第1期17卷 123-133页

作者： Huijie Dong Zhengxing Wu Min Tan Junzhi Yu state key laboratory of Management and Control for complex systems Institute of AutomationChinese Academy of SciencesBeijing 100190China university of Chinese Academy of sciences Beijing 100049China state key laboratory for turbulence and complex systems Department of Mechanics and Engineering ScienceBIC-ESATCollege of EngineeringPeking UniversityBeijing 100871China

This paper presents an innovative design for a biomimetic whale shark-like underwater glider aiming at the combination of high maneuverability and long *** a hybrid of the underwater glider and the robotic fish,its pectoral fins and tail can serve as not only the external control surfaces for attitude regulation during gliding but also the propellers for agile fish-like swimming *** verify the gliding capability of the whale shark-like glider and prepare for future dynamic analysis,the hydrodynamic coefficients,including drag,lift,sliding force,and corresponding moments are estimated through computational fluid dynamics *** addition,the hydrodynamic analyses of the proposed glider and an equivalent conventional glider during steady gliding motion are executed for *** experiments are performed to verify the downward gliding *** results reveal that the whale shark-like glider has less drag as well as higher lift-to-drag ratio and a markable gliding capability in *** may offer important inspiration for improving the gliding efficiency and performance of an underwater glider in biomimetic shape design.

关键词： biomimetic robot CFD hydrodynamic analysis underwater glider

来源：

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

Distributed consensus for multiple Euler-Lagrange systems: An event-triggered approach

引用

Science china(Technological sciences) 2016年第1期59卷 33-44页

作者： HUANG Na DUAN ZhiSheng ZHAO Yu state key laboratory for turbulence and complex systems Department of Mechanics and Engineering Science College of EngineeringPeking University

Distributed consensus problems for multiple Euler-Lagrange systems are addressed on the basis of event-triggered information in this study. Distributed consensus protocols are first designed in terms of two event-triggered scenarios: a decentralized strategy and a distributed strategy. Sufficient conditions that guarantee the event-triggered consensus for multiple Euler-Lagrange systems are then presented, with the associated advantages of reducing controller update times. It is shown that the Zeno behavior of triggering time sequences is excluded for both strategies. Finally, multiple Euler-Lagrange systems that consist of six two-link manipulators are considered to illustrate the effectiveness of the proposed theoretical algorithms.

关键词： consensus event-triggered strategy Euler-Lagrange system distributed control

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Simultaneous attack of a stationary target using multiple missiles: a consensus-based approach

引用

Science china(Information sciences) 2017年第7期60卷 67-80页

作者： Jialing ZHOU Jianying YANG Zhongkui LI state key laboratory for turbulence and complex systems Department of Mechanics and Engineering ScienceCollege of Engineering Peking University

This paper considers the simultaneous attack problem of multiple missiles against a stationary target. Built upon the classic proportional navigation structure, we propose a consensus-based approach to design the cooperative guidance law. Specifically, we present time-varying navigation ratios for the missiles,which exchange the time-to-go estimates between neighboring missiles via a communication network. For the cases where the communication topology is undirected or in the leader–follower structure with a missile acting as the leader whose navigation ratio cannot be tuned, we show that the proposed cooperative guidance law can solve the simultaneous attack problem. The effectiveness of the theoretical results is finally illustrated by numerical simulations.

关键词： simultaneous attack consensus problem cooperative control distributed control guidance law design

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Dynamic crack growth in a fiber-reinforced composite plate

引用

Chinese Science Bulletin 2005年第15期50卷 1565-1569页

作者： LIU Kaixin LIU Weifu Zhang dinxiang LI Rong ZHANG Guohua FU Bin state key laboratory for turbulence and complex systems and department of mechanics and engineering Science Peking University100871 China

This paper reports an experiment on the failure of a precracked plate made of unidirectional glass-epoxy fi-ber-reinforced composites subjected to three-point bending impact load. In the experiment, the whole process of crack growth was recorded by using high-speed photographic technique, in which a transmitted light path was adopted. Moreover, a new phenomenon of dynamic fracture has been observed. Based on the results, some preliminary studies have been carried out on the rate and path of the crack growth, as well as the failure mode.

关键词：支架桥面光纤加固合成高速摄影动态断裂过程

来源：

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

Formation control for nonholonomic agents using passivity techniques

引用

Applied Mathematics and mechanics(English Edition) 2010年第1期31卷 27-36页

作者：吴凡耿志勇 state key laboratory for turbulence and complex systems Department of Mechanics and Aerospace EngineeringPeking University

This paper studies the problem of the formation control for the multiple nonholonomic agents on a plane. A dynamic feedback linearization method is used to transform the dynamical model of each agent into two third-order integrator chains. A decentralized formation control law with the inter-agent damping .injection is derived. The asymptotical stability of the overall system is proven using the Lyapunov method. The simulation of the formation maneuver of a planar vehicle shows the effectiveness of the proposed method.

关键词： nonholonomic agents formation full-state linearization passivity

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Relative Scaling Exponents and Intermittency in Compressible Turbulent Channel Flows

引用

Chinese Physics Letters 2005年第12期22卷 3115-3118页

作者：胡凯衡陈凯 state key laboratory for turbulence and complex systems and department of mechanics and engineering Science Peking University Beijing 100871 Institute of Mountain Hazards and Environment Chinese Academy of Sciences Chengdu 610041

The relative scaling exponents and intermittency of three-dimensional compressible turbulent channel flow are investigated by using direct numerical simulation. One case is subsonic flow （Mα=0.8）, the other is supersonic （Mα=1.3）, and the Reynolds numbers based on the mean bulk velocity and channel half-width are 2826 and 3010, respectively. The analysis of the local slopes of sixth order velocity structure function to third order reveals that there is a well-defined scaling range for 10〈y^＋〈100. it is also noted that the intermittency of longitudinal velocity increments in this region is stronger than that of the transverse ones. Comparison with the incompressible case shows that the location of the most intensive intermittency moves toward the log-law region, which is related to the displacement of streamwise vortical structures in the near-wall region.

关键词： REYNOLDS-NUMBER LAWS

来源：

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

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：