检索结果-内蒙古大学图书馆

One family of 13315 stable periodic orbits of non-hierarchical unequal-mass triple systems

Science China(Physics,Mechanics & Astronomy) 2021年第1期64卷 108-113页

作者： XiaoMing Li XiaoChen Li ShiJun Liao MOE Key Laboratory of Disaster Forecast and Control in Engineering School of Mechanics and Construction EngineeringJinan UniversityGuangzhou510632China Department of Earth Atmospheric and Planetary SciencesMassachusetts Institute of TechnologyCambridge02139USA School of Civil Engineering and Transportation South China University of TechnologyGuangzhou510641China Department of Engineering Science University of OxfordOxfordOX13PJUK Center of Advanced Computing School of Naval ArchitectureOcean and Civil EngineeringShanghai Jiao Tong UniversityShanghai200240China School of Physics and Astronomy Shanghai Jiao Tong UniversityShanghai200240China

The three-body problem can be traced back to Newton in 1687,but it is still an open question *** that only a few periodic orbits of three-body systems were found in 300 years after Newton mentioned this famous *** triple systems are common in astronomy,practically all observed periodic triple systems are hierarchical(similar to the Sun,Earth and Moon).It has traditionally been believed that non-hierarchical triple systems would be unstable and thus should disintegrate into a stable binary system and a single star,and consequently stable periodic orbits of non-hierarchical triple systems have been expected to be rather ***,we report here one family of 135445 periodic orbits of non-hierarchical triple systems with unequal masses;13315 among them are *** with the narrow mass range(only 10-5)in which stable"Figure-eight"periodic orbits of three-body systems exist,our newly found stable periodic orbits have fairly large mass *** find that many of these numerically found stable non-hierarchical periodic orbits have mass ratios close to those of hierarchical triple systems that have been measured with astronomical *** implies that these stable periodic orbits of non-hierarchical triple systems with distinctly unequal masses quite possibly can be observed in *** investigation also suggests that there should exist an infinite number of stable periodic orbits of non-hierarchical triple systems with distinctly unequal *** that our approach has general meaning:in a similar way,every known family of periodic orbits of three-body systems with two or three equal masses can be used as a starting point to generate thousands of new periodic orbits of triple systems with distinctly unequal masses.

关键词： three-body problem non-hierarchical system periodic orbits

来源：评论

学校读者我要写书评

暂无评论

R-Function and variation method for bending problem of clamped thin plate with complex shape

引用

ADVANCES IN MECHANICAL engineering 2021年第7期13卷

作者： Xia, Fengfei Li, Shanqing Jinan Univ Sch Mech & Construct Engn MOE Key Lab Disaster Forecast & Control Engn Guangzhou 510623 Peoples R China

Solving ordinary thin plate bending problem in engineering, only a few analytical solutions with simple boundary shapes have been proposed. When using numerical methods (e.g. the variational method) to solve the problem, the trial functions can be found only it exhibits a simple boundary shape. The R-functions can be applied to solve the problem with complex boundary shapes. In the paper, the R-function theory is combined with the variational method to study the thin plate bending problem with the complex boundary shape. The paper employs the R-function theory to express the complex area as the implicit function, so it is easily to build the trial function of the complex shape thin plate, which satisfies with the complex boundary conditions. The variational principle and the R-function theory are introduced, and the variational equation of thin plate bending problem is derived. The feasibility and correctness of this method are verified by five numerical examples of rectangular, I-shaped, T-shaped, U-shaped, and L-shaped thin plates, and the results of this method are compared with that of other literatures and ANSYS finite element method (FEM). The results of the method show a good agreement with the calculation results of literatures and FEM.

关键词： Complex shape thin plate bending R-function trial function variational method

来源：评论

学校读者我要写书评

暂无评论

Study on axial compression performance of gfrp tube reactive power concrete composite short columns with encased steel 4

Study on axial compression performance of gfrp tube reactive...

引用

2021 4th International Conference on Civil, Architecture and Environment Research, ICCAER 2021

作者： Ji, Jing Song, Huayu Jiang, Liangqin Jiang, Li Heilongjiang Key Lab of Disaster Prevention Mitigation and Protection Engineering Northeast Petroleum University Heilongjiang Daqing163318 China Key Laboratory of Structural Disaster and Control of the Ministry of Education Harbin Institute of Technology Heilongjiang Harbin150090 China Key Laboratory of Earthquake Engineering and Engineering Vibration Institute of Engineering Mechanics China Earthquake Administration Harbin150086 China

In order to study the axial compression performance of the GFRP tube reactive power concrete composite short column with encased steel, a finite element model of the composite short column was established. The constitutive models of steel, RPC and GFRP were selected. The element selection and contact method of each component were explained. The boundary condition and mesh division of the composite column were determined. Based on this, finite element verification analysis of 6 specimens was performed by ABAQUS. The load-displacement curves and the axial compression bearing capacity were obtained. By comparing with the test, the reasonability of the constitutive model and the finite element model of this kind of column is verified. © 2021 Institute of Physics Publishing. All rights reserved.

关键词： Axial compression

来源：评论

学校读者我要写书评

暂无评论

Tensile Behavior of Uhpfrc Made by a Fiber Orientation Device with Adjustable Vibrational Frequency

SSRN

引用

SSRN 2023年

作者： Li, Zhihao Zhou, Wei School of Civil Engineering Key Lab of Structures Dynamic Behavior and Control Ministry of Education Key Lab of Smart Prevention and Mitigation of Civil Engineering Disaster Ministry of Industry and Information Technology Harbin Institute of Technology 73 Huanghe Road Nangang District Harbin150090 China

Ultra-High-Performance Fiber Reinforced Concrete (UHPFRC) not only has high compressive and tensile strength, but also exhibits strain-hardening characteristics in tension due to the addition of steel fibers. In this study, a new-style fiber orientation device equipped with a vibration motor of adjustable vibrational frequency was used to prepare UHPFRC. The wall effect and fiber length were considered in the manufacturing process of the device. Uniaxial tensile tests were conducted on fiber-oriented UHPFRC to explore the effects of vibrational frequency and corresponding vibrational force on the tensile behaviors. The test results showed that the elastic ultimate tensile strength, elastic ultimate tensile strain, tensile strength, peak tensile strain, and tensile elastic modulus of UHPFRC specimens cast by fiber orientation process at various vibrational frequencies were different. The fiber orientation parameters were quantitatively evaluated by the image analysis technique to explain the differences in tensile properties of the specimens. The effect of different vibrational frequencies on the tensile strength of UHPFRC matrix and its porosity was also considered. Therefore, this study provides a reference for how to adjust the vibrational frequency of the vibrating platform under the directional channel when pouring relevant components. © 2023, The Authors. All rights reserved.

关键词： Steel fibers

来源：评论

学校读者我要写书评

暂无评论

An Experimental Investigation of the Influence of Loading Rate on Rock Tensile Strength and Split Fracture Surface Morphology

引用

ROCK MECHANICS AND ROCK engineering 2021年第4期54卷 1969-1983页

作者： Cui, Zhen Qian, Sheng Zhang, Guimin Maochu, Zhang Chinese Acad Sci State Key Lab Geomech & Geotech Engn Inst Rock & Soil Mech Wuhan 430071 Hubei Peoples R China Univ Chinese Acad Sci Sch Engn Sci Beijing 10049 Peoples R China China Univ Min & Technol State Key Lab GeoMech & Deep Underground Engn Xuzhou 221116 Jiangsu Peoples R China Changjiang River Sci Res Inst Minist Water Resources Key Lab Geotech Mech & Engn Wuhan 430010 Hubei Peoples R China Jinan Univ MOE Key Lab Disaster Forecast & Control Engn Guangzhou 510632 Guangdong Peoples R China

To investigate the effect of the loading rate on the tensile strength of rock material and the morphology of the resulting split fracture surfaces, three types of rock specimens, namely, granite, basalt and limestone, were collected and tested with Brazilian testing under different loading rates. The tensile strength was measured, and the effect of the loading rate on the tensile strength of the rock material was studied. Digital terrain map models of the split fracture surface were obtained with an optical 3D scanning technique, and the effects of the loading rate on the geometry and morphology of the fracture surface were studied. The influence of the loading rate and tensile strength on the roughness was studied quantitatively by calculating the roughness indices of a fracture surface for all three kinds of rock. The research results show that the rock tensile strength increases with the loading rate. A linear relationship was established in double-logarithmic coordinates to describe the relationship between the tensile strength and the loading rate. Four different roughness indices were used to describe the morphology of the split fracture surface. The analysis results show that the magnitudes of all the roughness indices increase with the loading rate. Additionally, the roughness indices for all three types of rock linearly increase with the tensile strength. This linear trend indicates that it is possible to utilize fracture surface roughness indices to estimate rock tensile strength. The current study may motivate further research on the relationship between the morphology indices of rock fractures and mechanical parameters of the rock.

关键词： Rock material Brazilian test Loading rate Tensile strength Fracture surface morphology

来源：评论

学校读者我要写书评

暂无评论

Indirect Reconstruction of Structural Responses Based on Transmissibility Concept and Matrix Regularization

引用

SHOCK AND VIBRATION 2021年第1期2021卷

作者： Pan, Chudong Zhang, Liwen Sun, Zhuo Guangzhou Univ Sch Civil Engn Guangzhou Peoples R China Jinan Univ MOE Key Lab Disaster Forecast & Control Engn Guangzhou Peoples R China

A novel method is proposed based on the transmissibility concept and matrix regularization for indirectly measuring the structural responses. The inputs are some measured responses that are obtained via physical sensors. The outputs are the structural responses corresponding to some critical locations where no physical sensors are installed. Firstly, the transmissibility concept is introduced for expressing the relationship between the measured responses and the indirectly measured ones. Herein, a transmissibility matrix is formulated according to the theory of force identification under unknown initial conditions. Then, in order to reduce the size of the transmissibility matrix, structural responses are reshaped in a form of a matrix by using the concept of moving time windows. According to the matrix form of input-output relationship, indirect reconstruction of responses is boiled down to an optimization equation. Since inverse problem may be ill-conditioned, matrix regularization such as F-norm regularization is then recommended for improving the optimization problem. Herein, the penalty function is defined by using a weighted sum of two F-nonn values, which correspond to the estimated responses of physical sensors and the ones of the concerned critical locations, respectively. Numerical simulations and experimental studies are finally carried out for verifying the effectiveness and feasibility of the proposed method. Some results show that the proposed method can be applied for indirectly measuring the responses with good robustness.

关键词： Matrix algebra

来源：评论

学校读者我要写书评

暂无评论

An analytical method for shallow spherical shell free vibration on two-parameter foundation

引用

HELIYON 2021年第1期7卷 e05876页

作者： Gan, Jiarong Yuan, Hong Li, Shanqing Peng, Qifeng Zhang, Huanliang Jinan Univ Sch Mech & Construct Engn MOE Key Lab Disaster Forecast & Control Engn Guangzhou 510632 Peoples R China

The free vibration control differential equation of shallow spherical shell on two-parameter foundation is a four order differential equation. Using the intermediate variable, the four order differential equation is reduced to two lower order differential equations. The first lower order differential equation is a Helmholtz equation. A new method of two-dimensional Helmholtz operator is proposed as shown in the paper in which the Bessel function included in Helmholtz equation needs to be treated appropriately to eliminate singularity. The first lower order differential equation is transformed into the integral equation using the proposed method in the paper. The second lower order differential equation which is a Laplace equation is transformed into the integral equation by existing methods. Then the two integral equations are discretized according to the middle rectangle formula, and the corresponding solutions can be obtained by MATlab programming. In this paper, the R-function theory is used to select the appropriate boundary equation to eliminate the singularity. Based on the properties of R-function, the combined method of Helmholtz equation and Laplace equation can solve the free vibration problem of irregular shallow spherical shell on two-parameter foundation. Five examples are given to verify the feasibility of the method.

关键词： Shallow spherical shell Two-parameter foundation Helmholtz equation Laplace equation R-function Green's function

来源：评论

学校读者我要写书评

暂无评论

Computer transient simulation for dual in-line package through finite element analysis and ANASYS software 3

Computer transient simulation for dual in-line package throu...

引用

3rd International Conference on Electrical, Communication and Computer engineering, ICECCE 2021

作者： Su, Wei Luo, Wenhao Dong, Xianshan Chen, Si Tomar, Agam Science and Technology on Reliability Physics and Application Technology of Electronic Component Laboratory China Electronic Product Reliability and Environmental Testing Research Institute Guangzhou China MOE Key Lab of Disaster Forecast and Control in Engineering Guangzhou China School of Mechanics and Construction Engineering Jinan University Guangzhou China Faculty of Engineering and Mathematical Sciences University of Western Australia Australia

The reliability of the DIP package is studied by numerical simulation. Firstly, the DIP package, fixture and metal steel are modeled. Based on this, variable thickness papers are laid on the sample. According to the experiment, corresponding excitation and boundary condition are set. Then, the transient analysis result of DIP package is obtained through numerical simulation. The results show the relation of different thickness papers and acceleration-time curve, which provides a beneficial reference for the optimization of DIP packing. © 2021 Institute of Physics Publishing. All rights reserved.

关键词： Transient analysis

来源：评论

学校读者我要写书评

暂无评论

A new micro-macro transition for hyperelastic materials

引用

JOURNAL OF THE MECHANICS AND PHYSICS OF SOLIDS 2023年 171卷

作者： Zhan, Lin Wang, Siyu Qu, Shaoxing Steinmann, Paul Xiao, Rui Zhejiang Univ Dept Engn Mech State Key Lab Fluid Power & Mechatron Syst Key Lab Soft Machines & Smart Devices Zhejiang Pr Hangzhou 310027 Peoples R China Jinan Univ Coll Mech & Construct Engn Guangzhou 510632 Peoples R China Jinan Univ MOE Key Lab Disaster Forecast & Control Engn Guangzhou 510632 Peoples R China Friedrich Alexander Univ Erlangen Nuremberg Inst Appl Mech Egerland Str 5 D-91058 Erlangen Germany

Many classic hyperelastic models fail to predict the stress responses of soft materials in complex loading conditions with parameters calibrated through one simple test. To address this fundamental issue, we propose a new micro-macro transition for the microstructural hyperelasticity modeling, which is further integrated into the full network framework. With a Gaussian chain distribution, this new mapping scheme yields an explicit one-parameter hyperelastic model in terms of principal stretches. This new linear model achieves remarkable success in capturing the stress responses in multi-axial deformation modes for soft materials with an absence of strain stiffening effect, which is beyond the capability of the widely used neo-Hookean model. A new two-parameter hyperelastic model is further developed by combining the new micro-macro transition and non-Gaussian Langevin chain distribution. Compared with other two-parameter hyperelastic models based on Langevin statistics, such as the eight-chain model, affine full network model, and equilibrated microsphere model, our new model exhibits greatly improved predictive ability for complex loading types. The new model is also implemented for finite element analysis, which shows the ability to capture the responses of soft materials with heterogeneous strain distribution. In all cases, the parameters in our models can be determined through the data of uniaxial loading tests, along with the behaviors in other loading modes being well forecast, which is a challenge for various other existing hyperelastic models. This novel micro-macro transition is shown to properly capture the inherent correlations between different deformation modes, which may advance fundamentally modeling hyperelasticity and other constitutive behaviors for soft materials.

关键词： Micro-macro transition Hyperelastic model Multi-axial deformation Finite element simulation

来源：评论

学校读者我要写书评

暂无评论

Seasonal to interannual prediction of air pollution in China:Review and insight

引用

Atmospheric and Oceanic Science Letters 2022年第1期15卷 21-26页

作者： Zhicong Yin Huijun Wang Hong Liao Ke Fan Botao Zhou Key Laboratory of Meteorological Disaster Ministry of Education/Joint International Research Laboratory of Climate and Environment Change(ILCEC)/Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters(CIC-FEMD)Nanjing University of Information Science&TechnologyNanjingChina Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai) ZhuhaiChina Nansen-Zhu International Research Centre Institute of Atmospheric PhysicsChinese Academy of SciencesBeijingChina Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control Jiangsu Collaborative Innovation Center of Atmospheric Environment and Equipment TechnologySchool of Environmental Science and EngineeringNanjing University of Information Science&TechnologyNanjingChina School of Atmospheric Sciences Sun Yat-sen University/Guangdong Province Key Laboratory for Climate Change and Natural Disaster StudiesGuangzhouChina

Complex air pollution problems have resulted in considerable adverse impacts on the environment,human health,and economy in ***,owing to strict regulations since 2013,the air quality has been greatly ***,the prevention of air pollution has entered a critical stage in combination with climate change mitigation in *** seasonal to interannual prediction of air pollution(haze,surface 03,and sandstorms) could support the government in planning for air pollution control on an annual *** from all over the world have made great progress in understanding climate change and the variability of air pollution and associated physical mechanisms in China,which has provided a scientific basis for the development of climate prediction of air *** paper reviews the progress made in air-pollution climate prediction,and gives some critical insights including update of predictand,change of predictability,and development of coupled model.

关键词： Air pollution Climate prediction PM2.5 Ozone Sandstorm

来源：评论

学校读者我要写书评

暂无评论

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

请选择保存的检索档案：

请选择收藏分类：

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

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

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：