检索结果-内蒙古大学图书馆

Topology transition description of horseshoe vortex system in junctureflows with velocity characteristic lines

Theoretical & Applied Mechanics Letters 2024年第6期14卷 540-547页

作者： Bo Hu Hua Zhang Ran Li Qingkuan Liu State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures Shijiazhuang Tiedao UniversityShijiazhuang 050043China Department of Engineering Mechanics Shijiazhuang Tiedao UniversityShijiazhuang 050043China Ministry-of-Education Key Laboratory of Fluid Mechanics School of Aeronautical Science and EngineeringBeihang University(BUAA)Beijing 100191China School of Civil Engineering Shijiazhuang Tiedao UniversityShijiazhuang 050043China

Particle image velocimetry and numerical simulation results of juncture flows were analyzed to parametrically investigate topology transition. The vortex system evolutions from non-vortex to multi-vortex with variations in obstacle bluntness, obstacle width, flow velocity, and boundary layer thickness are discussed from the perspective of velocity characteristic lines. The velocity characteristic lines of u = 0, υ = 0, and ∇^(2) υ = 0 are adopted to describe the vortex system evolution. The motions of the characteristic lines with juncture flow parameters are described in detail, and the corresponding reflections of the vortex system patterns are illustrated. A panoramic picture of the development of velocity characteristic lines corresponding to the HSV topology transition from a non-vortex to a multi-vortex system with variations in the juncture flow parameter is established. Two methods for determining the attachment/separation pattern of the most upstream singularity are proposed. One method is based on the number of intersections of the u = 0 and υ = 0 velocity characteristic curve lines, and the other is based on the relative positions of the most upstream feet of the u = 0 and υ = 0 loop curves with both feet attached to the wall.

关键词： Juncture flow Topology transition Velocity characteristic lines

来源：评论

学校读者我要写书评

暂无评论

Gas control technology for coal and gas outburst mines based on new sealing materials

引用

Geohazard Mechanics 2024年第3期2卷 181-188页

作者： Hongwei Zhang Hongbao Zhao Dongliang Ji Shijie Jing Yuxuan Guo School of Energy and Mining Engineering China University of Mining and Technology(Beijing)Beijing100083China State Key Laboratory of Mechanical Behavior and System Safety of Trafﬁc Engineering Structures Shijiazhuang Tiedao UniversityShijiazhuang050043China

In order to solve the problem of gas overlimit in corner corners of coal and gas prominent mines, through thecombination of air leakage mechanism in the goaf, near-ﬁeld ﬁssure expansion and rich area division, blockingmaterial development and optimization, performance measurement of blocking materials and on-site test, westarted to study the causes of gas concentration in corner corners, analysis of roof collapse and transparency incorners and performance test of blocking materials, and optimized the blocking materials by combining laboratory test and engineering test. Considering the thickness of the sealing ﬁlm, the attenuation ratio of the sealingﬁlm thickness, the gelation time, and the gelation viscosity under different ratios, we designed a multi factororthogonal experiment to optimize the optimal ratio suitable for the engineering site. Factors affecting blockingeffectiveness, such as gel water retention and gel ﬂame resistance, were also tested. The sealing scheme wasimplemented in the 2109 working face of a coal and gas outburst mine in Gansu, China. Through on-sitemonitoring of the changes in temperature, gas concentration, and air leakage at each monitoring point beforeand after the use of sealing materials, the analysis of the detection results shows that the temperature changes ateach monitoring point after the use of sealing materials do not exceed 0.2C;The change in oxygen concentrationis less than 0.27 %;The gas concentration has decreased by more than 60 %, with a decrease of 71.32 % in the gasconcentration in the upper corner. The air leakage has decreased by more than 53 %, and the proportion ofdecrease in air leakage at the upper corner is as high as 56.83 %. This air leakage control technology hasremarkable blocking effect, meets the requirements of corner near-ﬁeld ﬁssure blocking material, and is easy toprepare, inexpensive, non-toxic, tasteless and green, providing a successful experience for the treatment of similarcoal and gas outburst min

关键词： Coal and gas outburst Air leakage in goaf Near-ﬁeldﬁssure Gas concentration Air leakage

来源：评论

学校读者我要写书评

暂无评论

Effect of Wheel-Rail Interface Friction Coefficient on Wheel Wear Evolution of Heavy Haul Locomotive 2nd

Effect of Wheel-Rail Interface Friction Coefficient on Wheel...

引用

2nd International Conference of mechanical system Dynamics, ICMSD 2023

作者： Kai, Hao Pengfei, Liu Chen, Wang bo, Liu Zhaoxin, Ma School of Mechanical Engineering Shijiazhuang Tiedao University Shijiazhuang050043 China State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures Shijiazhuang Tiedao University Shijiazhuang050043 China Key Laboratory of Mechanical Behavior Evolution and Control of Traffic Engineering Structures in Hebei Shijiazhuang Tiedao University Shijiazhuang050043 China School of Mechanical Engineering Hebei University of Architecture Zhangjiakou075000 China

ISBN: (纸本)9789819980475

Aiming at the serious problem of wheel wear of six-axle heavy haul locomotive, the wheel-rail interface friction theory is introduced to study the influence of different friction coefficients on wheel wear. The heavy haul locomotive-track coupling dynamic model and wheel wear model are established by UM software, and the rail top/rail side lubrication simulation conditions are set to analyze the evolution law of wheel profile and the change of wear amount. The results show that: The higher the friction coefficient of the rail top will reduce the tread wear of the first and third wheelset, but increase the flange wear rate. Under the friction coefficient of 0.40 at the rail top, the wear rates of the flanges of the first-to-third wheelset are 0.72, 0.41, and 0.52 mm/10,000 km, respectively. When the friction coefficient of the rail top is 0.40, the wear reduction rates of the flanges of the first-to-third wheelset are 16.88%, 9.97% and 9.11%, respectively, but the wear reduction of the flanges of the second wheelset is 0.20 mm under the friction coefficient of the rail top of 0.20. The research results provide a reference for wheel wear reduction of heavy haul locomotives, and provide a new idea for the research of locomotive wheel-rail interface friction management. © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024.

关键词： Flanges

来源：评论

学校读者我要写书评

暂无评论

Multi-field coupling and free vibration of a sandwiched functionally-graded piezoelectric semiconductor plate

引用

Applied Mathematics and Mechanics(English Edition) 2023年第8期44卷 1351-1366页

作者： Xueqian FANG Qilin HE Hongwei MA Changsong ZHU School of Environment and Civil Engineering Dongguan University of TechnologyDongguan 523808Guangdong ProvinceChina Guangdong Provincial Key Laboratory of Intelligent Disaster Prevention and Emergency Technologies for Urban Lifeline Engineering Dongguan University of TechnologyDongguan 523808Guangdong ProvinceChina State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures Shijiazhuang Tiedao UniversityShijiazhuang 050043China

Sandwiched functionally-graded piezoelectric semiconductor(FGPS)plates possess high strength and excellent piezoelectric and semiconductor properties,and have significant potential applications in micro-electro-mechanical *** multi-field coupling and free vibration of a sandwiched FGPS plate are studied,and the governing equation and natural frequency are derived with the consideration of electron *** material properties in the functionally-graded layers are assumed to vary smoothly,and the first-order shear deformation theory is introduced to derive the multi-field coupling in the *** total strain energy of the plate is obtained,and the governing equations are presented by using Hamilton’s *** introducing the boundary conditions,the coupling physical fields are *** numerical examples,the natural frequencies of sandwiched FGPS plates under different geometrical and physical parameters are *** is found that the initial electron density can be used to modulate the natural frequencies and vibrational displacement of sandwiched FGPS plates in the case of *** effects of the material properties of FGPS layers on the natural frequencies are also examined in detail.

关键词： sandwiched piezoelectric semiconductor(PS)plate functionally-graded layer multi-field coupling free vibration Hamilton's principle

来源：评论

学校读者我要写书评

暂无评论

Modeling,analysis,and simulation of X-shape quasi-zero-stiffness-roller vibration isolators

引用

Applied Mathematics and Mechanics(English Edition) 2022年第7期43卷 1027-1044页

作者： Xiaoye MAO Mengmeng YIN Hu DING Xiaofeng GENG Yongjun SHEN Liqun CHEN Shanghai Institute of Applied Mathematics and Mechanics Shanghai Key Laboratory of Mechanics in Energy EngineeringSchool of Mechanics and Engineering ScienceShanghai UniversityShanghai 200444China State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures Shijiazhuang Tiedao UniversityShijiazhuang 050043China

Existing quasi-zero stiffness(QZS)isolators are *** terms of their advantages,a novel X-shape QZS isolator combined with the cam-roller-spring mechanism(CRSM)is *** from the existing X-shape isolators,oblique springs are used to enhance the negative stiffness of the ***,the CRSM is used to eliminate the gravity of the loading mass,while the X-shape structure leaves its static *** existing QZS isolators are demonstrated and classified according to their nonlinearity mechanisms and classical *** is shown that the oblique spring can realize negative stiffness based on the simplest *** X-shape has a strong capacity of loading mass,while the CRSM can achieve a designed restoring force at any *** proposed isolator combines all these advantages *** on the harmonic balance method(HBM)and the simulation,the displacement transmissibilities of the proposed isolator,the X-shape isolators just with oblique springs,and the X-shape isolators in the traditional form are *** results show that the proposed isolator has the lowest beginning isolation frequency and the smallest maximum displacement ***,it still has some disadvantages similar to the existing QZS *** means that its parameters should be designed carefully so as to avoid becoming a bistable system,in which there are two potential wells in the potential energy curve and thus the isolation performance will be worsened.

关键词： quasi-zero stiffness(QZS) cam-roller X-shape isolator nonlinear isolation

来源：评论

学校读者我要写书评

暂无评论

Frost-resistant embankments with a novel ground source heat pump system

引用

Research in Cold and Arid Regions 2024年第6期16卷 292-301页

作者： TianFei Hu Li Wang TengFei Wang TieCheng Sun TianFeng Li State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures Shijiazhuang Tiedao UniversityShijiazhuangHebei 050043China School of Civil Engineering Shijiazhuang Tiedao UniversityShijiazhuangHebei 050043China Key Laboratory of High-Speed Railway Engineering Southwest Jiaotong UniversityMinistry of EducationChengduSichuan 610031China

This study introduces a novel artificial heating technique aimed at addressing frost heave issues in embankments on frozen ground,offering a sustainable *** evaluations assessed various heating systems,including boilers,heat pumps,solar heaters,and electric heaters,focusing on their thermal performance and *** study subsequently designed and implemented a direct-expansion ground source heat pump(DX-GSHP)system as the primary heat source for embankment *** testing confirmed the DX-GSHP system's ability to maintain a heat-supply temperature above 40℃ and a heat-absorption temperature below -3.5℃,effectively extracting geothermal energy for transfer to the topsoil *** a demonstrated coefficient of performance(COP)of 3.49,the DX-GSHP system not only proves its energy efficiency but also suggests a potential role in reducing the strain on electricity supply *** of DX-GSHPs,with heating capacities ranging from 1.0 to 2.0 kW and spaced at intervals of 2.0-4.0 m,provides a rapid thermal response to frost heave in singletrack railway embankments,thereby potentially mitigating frost-induced damage in cold climate regions.

关键词： Frost heave Embankment Artificial heating Ground source heat pump Coefficient of performance

来源：评论

学校读者我要写书评

暂无评论

Modeling and experiment study of hydraulically damped rubber mount under larger amplitude excitation at low frequency

引用

Noise and Vibration Worldwide 2023年第1期54卷 31-43页

作者： Liao, Xin Chen, Lin Wang, Hu Pei, Xin School of Mechanical Engineering Shijiazhuang Tiedao University Shijiazhuang China State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures Shijiazhuang Tiedao University Shijiazhuang China School of Mechanical Engineering Southeast University Nanjing China 14th Institute of China Electronic Technology Corporation Nanjing China

To improve the ride comfort of the cab of construction machinery and reduce the harm of vibration to the driver, a nonlinear lumped parameter model of passive hydraulic damping rubber mount (PHDRM) is first proposed. The nonlinearity of multi-inertial tracks is fully considered. Then, the global FE (finite element) fluid-solid coupling model of the isolator is developed in ABAQUS. The multi-field coupling solution and a joint simulation mode are employed in this paper. Meanwhile, the rubber element and inertial track parameters are identified respectively. Finally, multiple sets of dynamic performance experiments are performed on the different PHDRM samples. The experiment results indicate that the simulation results for two modeling methods of the vibration isolation system are consistent with the experimental datum. The modeling approaches have both reliability and accuracy under larger amplitude excitation at low frequency. Furthermore, the effects of different rubber elements and inertial track of PHDRM on low-frequency dynamic characteristics under larger amplitude are investigated and discussed, respectively. The experimental outcomes also provide a practical reference value for nonlinear modeling method research and dynamic performance analysis of PHDRM with complex structures further. © The Author(s) 2023.

关键词： Rubber

来源：评论

学校读者我要写书评

暂无评论

Evolution Rule of Wheel Tread Wear of High-Speed train and its Influence on Dynamic Performance

Evolution Rule of Wheel Tread Wear of High-Speed Train and i...

引用

2024 IEEE International Conference on Sensing, Diagnostics, Prognostics, and Control, SDPC 2024

作者： Wang, Peng Liu, Zhenkai Liu, Yongqiang Yang, Shaopu Cai, Yuqiang College of Mechanical Engineering North China University of Science and Technology Tangshan China School of Mechanical Engineering Shijiazhuang Tiedao University Shijiazhuang China Safety of Traffic Engineering Structures Shijiazhuang Tiedao University State Key Laboratory of Mechanical Behavior and System Shijiazhuang China

ISBN: (纸本)9798350388855

To investigate the influence of wheel wear evolution on wheel-rail contact and dynamic performance of high-speed trains, taking a high-speed train as the research object, the wheel wear tracking test was carried out to analyze the evolution law of wheel wear with the running mileage. Using the wheel-rail contact geometric relationship and non-Hertz rolling contact theory, the influence of wheel wear on wheel-rail contact geometric characteristics and contact mechanical characteristics was calculated, and the wheel-rail matching performance under wear was analyzed. The vehicle model was established by UM software, and the influence of different wheel wear treads on the vehicle's dynamic performance in a lathing cycle was investigated. The results indicate that during the evolution of wheel profile, the distribution state of wheel-rail contact points changes. With the increase of wheel tread wear, the radius difference of wheel rolling circles increases, which is conducive to improving the curve passing performance of vehicles. The wear of wheel tread leads to the increase of vehicle transmissibility and the decrease of nonlinear critical speed. © 2024 IEEE.

关键词： Gear trains

来源：评论

学校读者我要写书评

暂无评论

Propagation of Rayleigh-type surface waves in a layered piezoelectric nanostructure with surface effects

引用

Applied Mathematics and Mechanics(English Edition) 2022年第3期43卷 327-340页

作者： Lele ZHANG Jing ZHAO Guoquan NIE Jinxi LIU State Key Laboratory of Mechanical Behavior and System Safety of Tra±c Engineering Structures Shijiazhuang Tiedao UniversityShijiazhuang 050043China Hebei Key Laboratory of Mechanics of Intelligent Materials and Structures Department of Engineering MechanicsShijiazhuang Tiedao UniversityShijiazhuang 050043China Department of Architecture Shijiazhuang Institute of Railway TechnologyShijiazhuang 050041China

This work investigates the dispersion properties of Rayleigh-type surface waves propagating in a layered piezoelectric nanostructure composed of a piezoelectric nanofilm over an elastic *** one of the most important features of nanostructures,surface effects characterized by surface stresses and surface electric displacements are taken into account through the surface piezoelectricity theory and the nonclassical mechanical and electrical boundary *** expressions of the dispersion equation are derived,and numerical results are provided to examine the effects of several surface-related parameters,including the surface elasticity,surface piezoelectricity,surface dielectricity,surface density,as well as surface residual stress,on the dispersion modes and phase *** size-dependent dispersion behaviors occurring with surface effects are also predicted,and they may vanish once the thickness of the piezoelectric nanofilm reaches a critical value.

关键词： surface effect surface piezoelectricity dispersion behavior piezoelectric nanofilm Rayleigh wave

来源：评论

学校读者我要写书评

暂无评论

AFS/DYC Control of In-Wheel Motor Drive Electric Vehicle With Adaptive Tire Cornering Stiffness 6

AFS/DYC Control of In-Wheel Motor Drive Electric Vehicle Wit...

引用

6th CAA International Conference on Vehicular Control and Intelligence, CVCI 2022

作者： Li, Shaohua Yang, Zekun Shijiazhuang Tiedao University Behavior and System Safety of Traffic Engineering Structures State Key Laboratory of Mechanical Shijiazhuang China

ISBN: (数字)9781665453745

ISBN: (纸本)9781665453745

A linear tire model with constant conering stiffness does not guarantee the model accuracy, while a traditional nonlinear tire model has to face complicated parameter adjustment problems. In order to improve the adaptive capability of path tracking controller for a in-wheel motor drive electric vehicle (IDEV), the cornering stiffness is regarded as a time-varying parameter when tire sideslip angle increases. For the upper controller, the lateral tire force is estimated online based on square root cubature Kalman filter (SRCKF) to solve the cornering stiffness uncertainty. Then a prediction model of MPC with cornering stiffness modified is proposed to reduce the effect of model mismatch. For the lower controller, an active front steering control (AFS) and direct yaw moment control (DYC) based on integrated MPC is designed to track path and improve handling stability. The proposed control strategy is verified under extreme conditions through CarSim/Simulink simulation. It is shown that the strategy effectively improves the accuracy of path tracking and the stability of vehicle compared with the conventional MPC controller. © 2022 IEEE.

关键词： Tires

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：