Experimental study on dynamic performance of typical nonballasted track systems using a full-scale test rig

2016 ◽  
Vol 231 (4) ◽  
pp. 470-481 ◽  
Author(s):  
Mingze Wang ◽  
Chengbiao Cai ◽  
Shengyang Zhu ◽  
Wanming Zhai
Keyword(s):  
Experimental Study ◽  
Dynamic Stiffness ◽  
Dynamic Performance ◽  
Full Scale ◽  
Damping Coefficient ◽  
Full Scale Test ◽  
Test Rig ◽  
Scale Test ◽  
Stiffness And Damping Coefficient ◽  
Stiffness And Damping

This paper presents an experimental study on dynamic performance of China Railway Track System (CRTS) series track systems using a full-scale test rig. The test rig has been constructed based on 55.17 m long full-scale nonballasted tracks composed of four typical CRTS track elements in high-speed railways. First, the dynamic characteristics of different nonballasted tracks are investigated by conducting wheel-drop tests, where a wheel-drop testing vehicle with a dropping wheelset is devised to provide the wheel-drop load. The vibration levels of different track systems are assessed by the root-mean-square acceleration per one-third octave band, and the vibration transmission characteristics of the CRTS series tracks are evaluated by transfer functions. Further, a mathematical track model is used to extract the dynamic stiffness and damping coefficient of the four types of nonballasted track systems based on the wheel–rail impact response. The vibration characteristics, the dynamic stiffness, and damping coefficient of different nonballasted track systems under various wheel-drop heights are compared and discussed in detail.

Modeling and Validation of Rotational Vibration Responses for Accessory Drive Systems—Part I: Experiments and Belt Modeling

2013 ◽  
Vol 135 (3) ◽  
Author(s):  
Wen-Bin Shangguan ◽  
Xiang-Kun Zeng
Keyword(s):  
Friction Coefficient ◽  
Dynamic Stiffness ◽  
Excitation Frequency ◽  
Excitation Amplitude ◽  
Bending Stiffness ◽  
Damping Coefficient ◽  
Test Rig ◽  
Longitudinal Dynamic ◽  
Stiffness And Damping Coefficient ◽  
Stiffness And Damping

Experimental and modeling techniques for belt longitudinal static stiffness, longitudinal dynamic stiffness and damping coefficient, bending stiffness, and friction coefficient between a pulley and a belt are presented. Two methods for measuring longitudinal dynamic stiffness and damping coefficient of a belt are used, and the experimental results are compared. Experimental results show that the longitudinal dynamic stiffness of a belt is dependent on belt length, pretension, excitation amplitude and excitation frequency, and the damping coefficient of a belt is dependent on excitation frequency. Two models are presented to model the dependence of longitudinal dynamic stiffness and damping coefficient of a belt on belt length, pretension, excitation amplitude and excitation frequency. The proposed model is validated by comparing the estimated dynamic stiffness and damping with the experiment data. Also, the measurements of belt bending stiffness are carried out and the influences of the belt length on the belt bending stiffness are investigated. One test rig for measuring friction coefficient between a pulley and a belt are designed and fabricated, and the friction coefficient between the groove side belt with the groove side pulley, and the flat side belt with a flat pulley is measured with the test rig. The influences of wrap angle between pulley and belt, pretension of belt and rotational speed of the pulley on the friction coefficient are measured and analyzed. Taking an engine front end accessory drive system (FEAD) as the research example for the accessory drive system, experimental methods and the static and dynamic characteristics for the FEAD with seven pulleys, a tensioner, and a serpentine belt are presented.

Numerical analysis of the dynamic performance of aerostatic thrust bearings with different restrictors

2018 ◽  
Vol 233 (3) ◽  
pp. 406-423 ◽  
Author(s):  
Hailong Cui ◽  
Yang Wang ◽  
Xiaobin Yue ◽  
Yifei Li ◽  
Zhengyi Jiang
Keyword(s):  
Load Capacity ◽  
Dynamic Stiffness ◽  
Dynamic Performance ◽  
Dynamic Mesh ◽  
Eccentricity Ratio ◽  
Thrust Bearings ◽  
Stiffness And Damping Coefficient ◽  
Stiffness And Damping ◽  
The Impact ◽  
The Relationship

This study utilizes a dynamic mesh technology to investigate the dynamic performance of aerostatic thrust bearings with orifice restrictor, multiple restrictors, and porous restrictor. An experiment, which investigates the bearing static load capacity, was carried out to verify the calculation accuracy of dynamic mesh technology. Further, the impact of incentive amplitude, incentive frequency, axial eccentricity ratio, and non-flatness on the bearing dynamic performance was also studied. The results show incentive amplitude effect can be ignored at the condition of amplitude less than 5% film thickness, while the relationship between dynamic characteristics and incentive frequency presented a strong nonlinear relationship in the whole frequency range. The change law of dynamic stiffness and damping coefficient for porous restrictor was quite different from orifice restrictor and multiple restrictors. The bearing dynamic performance increased significantly with the growth of axial eccentricity ratio, and the surface non-flatness enhanced dynamic performance of aerostatic thrust bearings.

scholarly journals Influence of Floating Ring Seal Working Condition Parameters on the Dynamic Characteristics of Transient Gas Film

2021 ◽  
Vol 2108 (1) ◽  
pp. 012087
Author(s):  
Lishan Xu ◽  
Weizheng Zhang ◽  
Junjie Lu ◽  
Zhu Liu
Keyword(s):  
Film Thickness ◽  
High Speed ◽  
Dynamic Stiffness ◽  
Dynamic Performance ◽  
Spiral Groove ◽  
Low Leakage ◽  
Ring Seal ◽  
Stiffness And Damping Coefficient ◽  
Small Perturbation Method ◽  
Stiffness And Damping

Abstract The high requirements for sealing performance in high-speed rotating machinery has led to the design of floating seal with annular spiral groove that offer the advantages of low leakage and extended stability. However, efforts to model the dynamic performance of these floating seal have suffered from the great complexity of the flow field. The present work addresses this issue by establishing a transient Reynolds formulation of a floating seal with annular spiral groove in a rotating coordinate system based on the small perturbation method. In addition, the influence of radial eccentricity and film thickness on the solution divergence and calculation accuracy is calculated. The dynamic stiffness and dynamic damping matrixes are built. Then the variation rules of the dynamic stiffness and damping coefficient of the gas film with structure and working conditions are investigated in detail. The results show that the floating ring seal is more suitable for the service conditions of small film thickness, low pressure, high speed and large eccentricity. Accordingly, the results obtained lay a theoretical foundation for evaluating real-world applications of floating ring seal.

Simulated Drilling Testing of an Active Wellbore Sealing System on a Full-Scale Test Rig

2019 ◽  
Author(s):  
Austin Johnson ◽  
Jess Nichols ◽  
Kareem Ameen ◽  
Justin Fraczek
Keyword(s):  
Full Scale ◽  
Full Scale Test ◽  
Test Rig ◽  
Scale Test

scholarly journals Active Control Method Based on Equivalent Stiffness and Damping Coefficient for an Electromagnetic Isolation System

2020 ◽  
Vol 10 (22) ◽  
pp. 7953
Author(s):  
Lei Zhang ◽  
Xiangtao Zhuan
Keyword(s):  
Control Method ◽  
Dynamic Performance ◽  
Damping Coefficient ◽  
Stiffness Coefficient ◽  
Equivalent Stiffness ◽  
Isolation System ◽  
Performance Indexes ◽  
Stiffness And Damping Coefficient ◽  
Stiffness And Damping ◽  
Active Control Method

For improving the performance of an electromagnetic isolation system with reasonable parameters and avoid the parameter tuning problem of a PID controller, an active control method is put forward based on equivalent stiffness and damping coefficient. In this paper, the range of equivalent stiffness coefficient and damping coefficient of the electromagnetic force are calculated based on the required range of dynamic performance indexes. According to the nonlinear expression between electromagnetic force and coil current and gap, the relationships between the coil current and equivalent stiffness coefficient and damping coefficient are established. Then, the equivalent stiffness coefficient and damping coefficient can be satisfied by the controlled current in different gaps for meeting the required dynamic performance indexes. For reducing the maximum overshoot and the number of oscillations of the system, the active control method with the piecewise equivalent stiffness and damping coefficient is proposed based on the piecewise control strategy to realize the variable control parameters of the isolation system. Simulation and experimental results verify that the control method based on the equivalent stiffness and damping coefficient can obtain the desired dynamic performance indexes and the proposed control method with the piecewise strategy can not only reduce the setting time of the system, but also ensure the stability of the system.

scholarly journals Unbalance Compensation of a Full Scale Test Rig Designed for HTR-10GT: A Frequency-Domain Approach Based on Iterative Learning Control

2017 ◽  
Vol 2017 ◽  
pp. 1-15 ◽  
Author(s):  
Ying He ◽  
Lei Shi ◽  
Zhengang Shi ◽  
Zhe Sun
Keyword(s):  
Frequency Domain ◽  
Iterative Learning Control ◽  
Learning Control ◽  
Magnetic Bearing ◽  
Iterative Learning ◽  
Full Scale ◽  
Full Scale Test ◽  
Test Rig ◽  
Operation Speed ◽  
Scale Test

Unbalance vibrations are crucial problems in heavy rotational machinery, especially for the systems with high operation speed, like turbine machinery. For the program of 10 MW High Temperature gas-cooled Reactor with direct Gas-Turbine cycle (HTR-10GT), the rated operation speed of the turbine system is 15000 RPM which is beyond the second bending frequency. In that case, even a small residual mass will lead to large unbalance vibrations. Thus, it is of great significance to study balancing methods for the system. As the turbine rotor is designed to be suspended by active magnetic bearings (AMBs), unbalance compensation could be achieved by adequate control strategies. In the paper, unbalance compensation for the Multi-Input and Multi-Output (MIMO) active magnetic bearing (AMB) system using frequency-domain iterative learning control (ILC) is analyzed. Based on the analysis, an ILC controller for unbalance compensation of the full scale test rig, which is designed for the rotor and AMBs in HTR-10GT, is designed. Simulation results are reported which show the efficiency of the ILC controller for attenuating the unbalance vibration of the full scale test rig. This research can offer valuable design criterion for unbalance compensation of the turbine machinery in HTR-10GT.

scholarly journals Calibration and validation of the dynamic response of two slab track models using data from a full-scale test rig

2021 ◽  
Vol 234 ◽  
pp. 111980
Author(s):  
Jannik S. Theyssen ◽  
Emil Aggestam ◽  
Shengyang Zhu ◽  
Jens C.O. Nielsen ◽  
Astrid Pieringer ◽  
...  
Keyword(s):  
Dynamic Response ◽  
Full Scale ◽  
Full Scale Test ◽  
Test Rig ◽  
Slab Track ◽  
Calibration And Validation ◽  
Scale Test ◽  
Using Data

A full scale test rig for assessment of abrasive wear of shackle chains

Wear ◽  
2013 ◽  
Vol 302 (1-2) ◽  
pp. 1017-1025 ◽  
Author(s):  
J. De Pauw ◽  
P. De Baets ◽  
Y. Perez Delgado ◽  
J. Sukumaran ◽  
W. Ost
Keyword(s):  
Abrasive Wear ◽  
Full Scale ◽  
Full Scale Test ◽  
Test Rig ◽  
Scale Test

Experimental study on joint of spliced steel–PSC hybrid girder, part II: Full-scale test of spliced hybrid I-girder

2011 ◽  
Vol 33 (9) ◽  
pp. 2668-2682 ◽  
Author(s):  
Sang-Hyo Kim ◽  
Chan-Goo Lee ◽  
Sung-Jae Kim ◽  
Jeong-Hun Won
Keyword(s):  
Experimental Study ◽  
Full Scale ◽  
Full Scale Test ◽  
Scale Test

A novel technique to compute static and dynamic performance characteristics of aerostatic thrust bearing

2018 ◽  
Vol 70 (1) ◽  
pp. 84-96 ◽  
Author(s):  
Saurabh Kumar Yadav ◽  
Arvind Kumar Rajput ◽  
Nathi Ram ◽  
Satish Chandra Sharma
Keyword(s):  
Finite Element ◽  
Thrust Bearing ◽  
Dynamic Performance ◽  
Finite Element Formulation ◽  
Damping Coefficient ◽  
Element Formulation ◽  
Content Type ◽  
Novel Technique ◽  
Stiffness And Damping Coefficient ◽  
Stiffness And Damping

Purpose This study aims to analyze the dynamic performance of aerostatic thrust bearing for different geometries of recess. Different geometries of recess of equal recess area, i.e. circular, elliptical, rectangular and annular, have been considered in analysis. The work also analyzes the influence of tilt angle on the performance of thrust bearing. To compute the unknown pressure field, the Reynolds equation governing the flow of compressible lubricant (air) has been solved using finite element formulation. Further, separate finite element formulations have been carried out to compute fluid film stiffness and damping coefficients directly. This method provides quick computation of stiffness and damping coefficients of aerostatic thrust bearing than the usual approach. Design/methodology/approach As the Reynolds equation governing the flow of compressible lubricant is nonlinear partial differential equation, the computation of the stiffness and damping coefficient follows an iterative procedure. It requires a lot of computational energy. Therefore, in the present work, a novel technique based on finite element formulation is suggested to compute air film stiffness and damping coefficient in aerostatic thrust bearing. Findings A novel technique based on finite element formulation is illustrated to simulate the performance of tilted pad aerostatic thrust bearing. On the basis of simulated results, following key conclusions may be drawn. The static and dynamic performance of a circular aerostatic tilted thrust pad bearing is significantly affected with a change in the value of tilt parameter and the shape of the recess. Research limitations/implications Implications are as follows: direct computation of air film damping coefficient is performed without perturbation method in finite element method (FEM); influence of tilt on aerostatic thrust bearing is studied; influence of recess shape on aerostatic thrust bearing is observed; and finite element formulation of aerostatic thrust bearing is performed. Originality/value The present work will be quite useful for bearing designer and academicians.

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