检索结果-内蒙古大学图书馆

Experiment Research on Emergency Stop Vibrations of key Components in the Friction Vertical Lifting System

SHOCK AND VIBRATION 2022年第0期2022卷

作者： Peng, Qifeng Xu, Peng Li, Yukun Yuan, Hong Xue, Zhangna Yang, Jinchuan China Univ Petr East China Coll Pipeline & Civil Engn Qingdao 266580 Peoples R China Jinan Univ Sch Mech & Construction Engn Key Lab Disaster Forecast & Control Engn MOE Guangzhou 510632 Peoples R China

In order to analyze emergency stop vibration of the friction vertical lifting system under different loads, a loading experiment was carried out, and the longitudinal vibration characteristics of the carriage, frame, and steel rope were measured during the emergency braking process of an elevator. Accordingly, it is found that the load mass does not affect the peak deceleration value of the car frame and the wire rope during downwards emergency stop. Then, vertical vibration is explored using the time-varying vibration analysis theory. The obtained results show that when analyzing the vibration of objects on both sides of the traction wheel, the deceleration of the wire rope on both sides of the traction wheel are not equal, and the influence of the pressure change during the traction-wheel friction should be considered in calculations. This article may provide a reference to calculate the steel rope tension of the elevator and mine hoist.

关键词： Wheels

来源：评论

学校读者我要写书评

暂无评论

Experimental study of magnetic bistable nonlinear energy sink for structural seismic control

引用

SOIL DYNAMICS AND EARTHQUAKE engineering 2023年 164卷

作者： Chen, Yangyang Su, Weite Tesfamariam, Solomon Qian, Zhichao Zhao, Wei Yang, Zhenyu Zhou, Fulin Guangzhou Univ Earthquake Engn Res & Test Ctr MOE Key Lab Earthquake Resistance Earthquake Miti Guangzhou 510006 Peoples R China Guangzhou Univ Guangdong Prov Key Lab Earthquake Engn & Appl Tec Guangzhou Peoples R China Univ British Columbia Sch Engn Okanagan Campus Kelowna BC Canada Jinan Univ Sch Mech & Construct Engn MOE Key Lab Disaster Forecast & Control Engn Guangzhou 510632 Peoples R China

In previous work, magnetic bistable nonlinear energy sink (MBNES) had been numerically demonstrated as an efficient absorber for seismic mitigation of shear-frame structures. The present paper, for the first time, exper-imentally investigates the MBNES device, as well as its control performance using both cyclic-load and shake -table tests. Both spatial magnetic force and sliding friction were included in the proposed MBNES model and the device was designed, manufactured, and assembled in the lab. The cyclic-load tests were conducted to validate and calibrate the theoretical model of the MBNES. Subsequently, a series of shake-table tests of a one-story shear frame equipped with the present MBNES device was performed. By a proposed algorithm, the nu-merical model of the control system was successfully identified based on the response data. A comparison of the experimental and numerical results revealed the accuracy of the identified numerical model. By using the present device, significant suppressions of the seismic responses were observed. The transient internal resonance cap-tures of the MBNES control system can also be observed during the seismic responses. The study experimentally demonstrates the potential of the MBNES device as an efficient absorber for seismic mitigation of structures.

关键词： Nonlinear energy sink Shake table test Cyclic-loading test Magnetic charge model Seismic mitigation

来源：评论

学校读者我要写书评

暂无评论

Structural damage detection based on modal feature extraction and multi-objective optimization method for steel structures

引用

FRONTIERS IN MATERIALS 2022年 9卷

作者： Chen, Zepeng Zhao, Di Chen, Zhou Wang, Wenxue Foshan Univ Sch Transportat & Civil Engn & Architecture Foshan Peoples R China Jinan Univ MOE Key Lab Disaster Forecast & Control Engn Guangzhou Peoples R China Kyushu Univ Res Inst Appl Mech Fukuoka Japan

Model updating based on intelligent algorithms has achieved great success in structural damage detection (SDD). But the appropriate selection of objective functions remains unclear and becomes an obstacle to applying the methods to real-world steel structures. In this paper, a multi-objective identification method based on modal feature extraction and linear weight sum was proposed, and the best weight values to gain the best solution were also determined. A hybrid particle swarm optimization (HPSO) was selected as a solver to update structural parameters for accurate SDD results. First of all, six single objective functions based on modal feature extraction were considered, and numerical simulations show that the one based on MTMAC indicator exhibits certain superiority over the other. In order to provide a fair comparison among different objective functions, a quantified indicator named damage vector consistency (DVC) is also defined, which describes the consistency between identified result and the assumed one. After that, a multi-objective identification method is formulated by linearly combining an MTMAC-based objective function and another selected single objective function. Different weight values were also investigated to find out the best solution for accurate SDD. Three numerical simulations were conducted, including a simply-supported beam, a two-story steel frame, and a 31-bar plane truss. Their SDD results verify the applicability of the proposed multi-objective optimization method. Some relative discussions are also described in detail.

关键词： structural damage detection (SDD) modal feature extraction multi-objective optimization damage vector consistency steel structures

来源：评论

学校读者我要写书评

暂无评论

Theoretical analysis and finite element simulation of pipeline structure in liquefied soil

引用

HELIYON 2021年第7期7卷 e07480页

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

A mechanical analysis model for the floating of buried pipelines in soil liquefaction areas is established in this paper. In order to improve the inherent defects of the elastic foundation beam method based on the Winkler model and increase the calculation accuracy, the Pasternak model is introduced and the interaction between soil and spring is considered. A mechanical analysis method for buried pipelines in liquefaction zone considering axial load is proposed in present paper. According to the Pasternak model and the deflection curve differential equation, the pipe bending deformation curve equation and the deformation coordination equation are derived. The analytical calculation method of the pipe mechanical response is established. A new method of the mechanical analysis of the floating of buried pipelines in the liquefaction zone is provided. The mechanical response of the pipeline under the conditions of different pipeline parameters and liquefaction zone length is analyzed. The reliability of the analysis method in this paper is verified by the comparison of finite element method (FEM). Considering that the previous researches of scholars mainly focused on straight pipes, there are few studies on the pipe structure nodes in liquefied soil. The mechanical properties of the three-way pipe structure in the soil liquefaction zone are analyzed by the finite element method (FEM). The influence of pipe diameter, wall thickness, liquefied soil density, transition zone length, buried depth, and pipeline internal pressure on the mechanical response of the pipeline is analyzed.

关键词： Buried pipeline Liquefied soil Pasternak model Pipeline node Mechanical response

来源：评论

学校读者我要写书评

暂无评论

Free Vibration of Axially Moving Functionally Graded Nanoplates Based on the Nonlocal Strain Gradient Theory

引用

INTERNATIONAL JOURNAL OF ACOUSTICS AND VIBRATION 2020年第4期25卷 587-596页

作者： Li, Cheng Wang, P. Y. Luo, Q. Y. Li, S. Soochow Univ Sch Rail Transportat Dept Vehicle Engn Suzhou 215131 Jiangsu Peoples R China Jinan Univ MOE Key Lab Disaster Forecast & Control Engn Guangzhou 510632 Guangdong Peoples R China

Using the nonlocal strain gradient theory, we explore vibration behaviours of initially bidirectional tensioned functionally graded nanoplates with axial speed. The governing equation of motion can be obtained based on the differential type of nonlocal strain gradient constitutive relation, which characters the dynamics of nanostructures containing kinematic relation. The simply supported boundary constraints on four sides are considered and subsequently the numerical results are determined. It shows that natural frequencies of axially moving nanoplates decrease when increasing the axial speed and the nonlocal parameter. Hence the nonlocal and kinematic factors cause the natural frequencies to decrease or, weaken the equivalent bending rigidity. On the other hand, natural frequencies increase with an increase in the axial tension and material characteristic scale. Hence the strain gradient and tensile stress factors cause the natural frequencies to increase or, strengthen the equivalent bending rigidity. In addition, the natural frequencies get higher with a larger aspect ratio of the functionally graded nanoplate. The larger one between the nonlocal parameter and the material characteristic scale plays a dominant role in the softening and stiffening mechanisms of the nonlocal strain gradient effect. In case of the same magnitude of the nonlocal parameter and the material characteristic scale, the softening and hardening phenomena disappear. The equivalent bending rigidity neither increases nor decreases in such a situation, and its value degenerates to the classical one.

关键词： Natural frequencies

来源：评论

学校读者我要写书评

暂无评论

Onsite Identification of Moving Vehicle Loads on Multispan Continuous Bridge Using Both Dictionary Expansion and Sparse Regularization

引用

JOURNAL OF AEROSPACE engineering 2021年第3期34卷 04021018-04021018页

作者： Liu, Huanlin Li, Cheng Yu, Ling Wang, Yafei Zhong, Jiwei Jinan Univ Sch Mech & Construct Engn MOE Key Lab Disaster Forecast & Control Engn 601 West Huangpu Ave Guangzhou 510632 Peoples R China State Key Lab Hlth & Safety Bridge Struct Wuhan 430034 Peoples R China Jinan Univ MOE Key Lab Disaster Forecast & Control Engn 601 West Huangpu Ave Guangzhou 510632 Peoples R China

Moving force identification (MFI) plays an important role in monitoring moving vehicle loads acting on a bridge, which has attracted great attention in recent years. Although many MFI methods have been proposed, their effectiveness in real bridges has not been carefully investigated. In this study, focusing on how to identify moving forces from structural responses in a real bridge, some important aspects are conducted and discussed in detail. The effectiveness of a MFI method based on dictionary expansion and sparse regularization is evaluated by a five-span continuous bridge in real engineering. First, a finite-element (1-b) model is established to approximately describe the real bridge. Then, the FE model is updated based on the modal information obtained from structural responses, so the transfer matrices between moving forces and structural responses can be calculated. Meanwhile, data preprocessing is conducted and a suitable dictionary is designed to obtain reasonable MFI results. As a result, the MFI equation by adding reweighted l(1)-norm regularization is used for MFI. Finally, two trucks with known gross vehicle weights are adopted to evaluate its effectiveness. The NM results show that this method can reasonably estimate the moving vehicle loads acting on bridge deck, and the identified moving forces are reasonable. (C) 2021 American Society of Civil Engineers.

关键词： Structural health monitoring (SHM) Moving force identification (MFI) Sparse regularization Dictionary expansion

来源：评论

学校读者我要写书评

暂无评论

Experimental verification on finite element model of composite columns with concrete filled steel tube flange 4

Experimental verification on finite element model of composi...

引用

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

作者： Ji, Jing Jiang, Li Jiang, Liangqin Song, Huayu 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 mechanical performance of composite columns with concrete-filled steel tube flange subjected to the eccentric compression, the finite element model of this kind of composite columns is established by using ABAQUS finite element software. In this paper, the reasonable material constitutive and finite element modelling method are selected to carry out numerical simulation analysis of concrete-filled steel tubular composite columns and concrete-filled square steel tubular columns. The load vertical displacement curves, load lateral deflection curves and failure modes are obtained, which are in good agreement with the existing test data. The rationality of material constitutive and finite element modelling is verified, which lays a foundation for further establishing the calculation formula of eccentric compression bearing capacity of this kind of column. © 2021 Institute of Physics Publishing. All rights reserved.

关键词： Flanges

来源：评论

学校读者我要写书评

暂无评论

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

引用

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

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：