Manufacturing Errors Effects on Disturbing Torque of Aerostatic Bearings

2009 ◽  
Vol 16-19 ◽  
pp. 505-509 ◽  
Author(s):  
Jing Shi Liu ◽  
Ya Zhou Sun ◽  
Li Hua Lu ◽  
Ying Chun Liang
Keyword(s):  
Finite Element ◽  
Zero Point ◽  
Mathematic Model ◽  
Position Angle ◽  
Major Influence ◽  
Eccentricity Ratio ◽  
Roundness Error ◽  
Setting Angle ◽  
Manufacturing Errors ◽  
Aerostatic Bearings

In order to improve the drifting accuracy of aerostatic bearings, the manufacturing errors effects on disturbing torque of aerostatic bearings is studied by using the finite element method. The finite element mathematic model of the major influence factors of disturbing torque is established. Then, the finite element equation in the gas film domain is solved and the disturbing torque in the presence of disturbing factors is calculated. The research focuses on elliptical error and prismatic error of journal and incline error of throttle slit. The setting angle of journal, incline position angle of throttle slit and radial eccentricity ratio which affect the disturbing torque is also studied. The results show that roundness error of journal and incline error of throttle slit affect the disturbing torque significantly, that is the greater roundness error of journal and incline error of throttle slit the greater disturbing torque. Disturbing torque is periodic function of setting angle of journal and incline position angle of throttle slit. Radial eccentricity ratio affects the disturbing torque, and there is specific radial eccentricity ratio makes disturbing torque to be extreme point or zero point. In the research, the theoretical disturbing torque value is compared with the experimental value of a certain aerostatic bearing, find that they are on the whole accordant with each other and then prove that the finite element model and the method use to solve the problem is correct. The research is of great significance for designing, manufacturing and assembling aerostatic bearings and for performance prediction of aerostatic bearings.

Factors Effect on Vortex Torque of Aerostatic Bearings

2010 ◽  
Vol 97-101 ◽  
pp. 3745-3748 ◽  
Author(s):  
Jing Shi Liu ◽  
Ya Zhou Sun ◽  
Li Hua Lu ◽  
Ying Chun Liang
Keyword(s):  
Finite Element ◽  
Orthogonal Design ◽  
Element Model ◽  
Eccentricity Ratio ◽  
Supply Pressure ◽  
Air Supply ◽  
Predicting Performance ◽  
Function Expression ◽  
Aerostatic Bearings ◽  
Torque Values

In order to improve the drift accuracy of aerostatic bearings, the air supply pressure and manufacturing errors effect on vortex torque of aerostatic bearings were studied by using the finite element method. This paper analyzed the influence of air supply pressure on vortex torque, in view of elliptical error, incline error of throttle slit and radial eccentricity ratio exist. The quadratic regression orthogonal design was adopted to establish function expression of vortex torque among air supply pressure, elliptical error, incline error of throttle slit and radial eccentricity ratio. In research, the simulation vortex torque values of a certain aerostatic bearing are compared with the experimental values. The predicted characteristics are in good agreement with experimental results and then prove that the finite element model, the method used to solve the problem and the function expression obtained are correct. The research has great significance for predicting performance and choosing the air supply pressure of aerostatic bearings.

scholarly journals A detailed investigation on thermal behaviour of slim floor beams with web openings at elevated temperatures

2019 ◽  
Vol 10 (4) ◽  
pp. 446-467
Author(s):  
Naveed Alam ◽  
Ali Nadjai ◽  
Olivier Vassart ◽  
Francois Hanus
Keyword(s):  
Finite Element ◽  
Thermal Behaviour ◽  
Elevated Temperatures ◽  
Major Influence ◽  
Web Openings ◽  
Content Type ◽  
Composite Action ◽  
Temperature Development ◽  
In Fire ◽  
Steel Section

Purpose In recent times, the use of steel sections with web openings has become common as slim floor beams because they offer a reduction in weight of the steelwork, accommodate services within the floor depth and provide the composite action. The composite action in these beams is achieved either through the concrete dowels or through concrete plugs. Though these web openings offer several benefits in slim floor beams, they induce the material discontinuity in the steel web, which may affect their shear capacity and/or thermal behaviour. The purpose of this study is to investigate the thermal behaviour of slim floor beams with web openings in fire. Design/methodology/approach This research presents findings from experimental and analytical investigations conducted to study the thermal behaviour of slim floor beams with web openings in fire. For this purpose, an experimental investigation was conducted, which shows that the presence of web openings has a major influence on temperature development across the steel section as well as along the span of these beams. The behaviour of the tested slim floor beam is validated using finite element modelling. The validated finite element model is then used to conduct a sensitivity study to analyse the influence of different opening spacings, sizes and shapes on the thermal performance of slim floor beams in fire. Findings Test results show that the presence of web openings has a major influence on temperature development across the steel section as well as along the span of these beams. Temperatures on the web below the openings are found to be higher as compared to those recorded on the adjacent solid steel web. It is also observed that temperatures on the steel web above the openings are lesser than those on the adjacent solid steel web. Parametric studies conducted using the verified analytical modelling methods show that different opening spacings, sizes and shapes have a variable impact on the thermal behaviour of slim floor beams in fire. Closely spaced and larger opening sizes were found to have a more severe influence on their thermal behaviour in fire as compared to widely spaced and smaller openings. It was also found that the behaviour of these beams is influenced by the shape of the openings with rectangular openings resulting in more severe thermal distributions as compared to circular openings. Originality/value The findings from this research study are highly valuable as they contribute to the existing knowledge database. There is a lack of experimental and analytical investigation on performance of slim floor beams with web openings at elevated temperatures. The results and conclusions from this study will help in developing innovative designs for slim floor beams and will help in reducing the fire related risk associated with structures comprising of slim floor beams with web openings.

scholarly journals Jet-disk connection in OJ287

2010 ◽  
Vol 6 (S275) ◽  
pp. 275-279
Author(s):  
Mauri J. Valtonen ◽  
Tuomas Savolainen ◽  
Kaj Wiik
Keyword(s):  
Black Hole ◽  
Time Lag ◽  
Zero Point ◽  
Position Angle ◽  
Viewing Angle ◽  
The Past ◽  
Basic Model ◽  
Optical Light Curve ◽  
The Mean ◽  
Free Parameters

AbstractA model for OJ 287 consisting of two orbiting black holes has been constructed using optical light curve data. The model has successfully predicted the occurrence of sharp optical outbursts of OJ 287 for the past 15 years. Here we test if also the variations in the radio jet position angle can be explained within the framework of this same model, which has most of its parameters fixed by the timing of the optical flares. The model applied here has only three free parameters left, the (trivial) zero point of the jet position angle, the time lag between changes in the disk and jet orientations, and the zero point of the viewing angle. Despite its simplicity and the small number of free parameters, the model appears to be able to reproduce the main properties of the observed position angle variations during the past 30 years. The best fits are obtained when the time lag is either ~4 or ~14 years. However, the jet orientation seems to be unrelated to the direction of the spin of the primary black hole. This implies, assuming that the basic model is correct, that the mean orientation of the jet is determined by the orientation of the inner accretion disk, not by the spin axis of the black hole.

Investigation on the uncertain factors of the elastic–plastic contact characteristics of the planetary roller screw mechanism

2018 ◽  
Vol 233 (5) ◽  
pp. 1795-1806
Author(s):  
Qin Yao ◽  
Yongshou Liu ◽  
Mengchuang Zhang ◽  
Geng Liu ◽  
Shangjun Ma
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Mathematic Model ◽  
Contact Analysis ◽  
Secondary Development ◽  
Elastic Plastic ◽  
Development Platform ◽  
Roller Screw ◽  
Screw Mechanism ◽  
Element Method

The scatter of uncertain factors of the planetary roller screw mechanism, which originated from the manufacturing process, has a significant influence on its serving performance. However, this influence remains insufficiently studied. Further, the elastic–plastic contact analysis of the planetary roller screw mechanism with considering the uncertainties needs large numbers of repetitive calculations by traditional finite element method, which is labor intensive and often impractical. In this paper, an uncertain model of the planetary roller screw mechanism, including parameterization and finite element calculation, is established to conduct the elastic–plastic contact analysis automatically. Besides, the finite element method results can be also obtained automatically with the self-compiled flow program and the secondary development platform using the design of experiment method. Then, a mathematic model is applied to value the influence of the uncertain factors on the contact characteristics. The Pareto graphs are plotted to clearly show this sequence of the percent effects of all the uncertain factors. The present work, for the first time, developed an automatic modeling method for analyzing efficiently the uncertain factors of planetary roller screw mechanism, which is worthy in industrial application.

Transmission Error Calculation Based on Manufacturing Errors and Load

2014 ◽  
Vol 971-973 ◽  
pp. 848-851 ◽  
Author(s):  
Jian Jie Tang ◽  
Jin Yuan Tang
Keyword(s):  
Shape Change ◽  
Mathematic Model ◽  
Transmission Error ◽  
High Accuracy ◽  
Calculation Model ◽  
Gear Teeth ◽  
Error Calculation ◽  
Pitch Error ◽  
Great Consistency ◽  
Manufacturing Errors

A valid mathematic model is introduced to study the calculation of gear meshing transmission error, which is based on the manufacturing error and gear teeth deformation. Subsequently, take a pair of specific gear for example;The transmission error curves are obtained by the calculation model. The results show great consistency with the curves from Romax software, which indicates the validity and high accuracy of the mathematic model presented above. And it can be found that the shape change of transmission error curves affected mainly by the pitch error under the same conditions as the precision.

Numerical Analysis of Torsional Effect of the Eccentric Structure Caused by the Running Train

2011 ◽  
Vol 71-78 ◽  
pp. 1329-1338
Author(s):  
Bi Tao Wu ◽  
Hua Xi Lu ◽  
Ping Ying Liang
Keyword(s):  
Finite Element ◽  
Numerical Analysis ◽  
Dynamic Model ◽  
Horizontal Displacement ◽  
Asymmetric Structure ◽  
Eccentricity Ratio ◽  
Finite Element Software ◽  
Horizontal Acceleration ◽  
Torsion Effect ◽  
Eccentric Structure

Application of finite element software ANSYS coupled with the train-ground dynamic model is developed to predict the torsion effect of asymmetric structure. Respectively analyze on eccentricity ratio is 0, 0.1, 0.3, 0.5, 0.7, 0.9, and 1.0. Results show that the ground vibrations by the train are slight. Eccentricity of the structure has certain effect on horizontal displacement, horizontal angle displacement, and floor horizontal acceleration.

Non-Iterative Finite Element Scheme for Combined Annular-Thrust Porous Aerostatic Bearings Analysis

2012 ◽  
Author(s):  
Polina V. Khan ◽  
Pyung Hwang
Keyword(s):  
Finite Element ◽  
Air Flow ◽  
Three Dimensional ◽  
Finite Element Scheme ◽  
Element Scheme ◽  
Numerical Example ◽  
Key Points ◽  
Aerostatic Bearings

The key points of method derivation and a numerical example for bearing with three dimensional air flow are presented.

Research on Strain Transfer of Beam Sensor Based on Ansys Workbench

2021 ◽  
Vol 105 ◽  
pp. 211-220
Author(s):  
Bei Li ◽  
Xiao Jun Zuo ◽  
Xiang Gao
Keyword(s):  
Finite Element ◽  
Finite Element Simulation ◽  
Mathematic Model ◽  
Stress And Strain ◽  
Strain Transfer ◽  
Element Simulation ◽  
Calibration Experiment ◽  
Beam Shear ◽  
Key Dimensions ◽  
Ansys Workbench

In this paper, the structural strain of the beam shear stress sensor is optimized, and the average strain of the strain sensor is simulated by Ansys Workbench. Firstly, the mathematic model of the beam sensor is established, and the stress and strain of the model are analyzed theoretically. Secondly, the finite element modeling of the sensor is carried out, and the finite element simulation of Ansys Workbench is carried out. The key dimensions of strain measurement are studied by parameter driven. Then the simulation results show that the effect of the production patch error on the output is quantitatively analyzed. Finally, the feasibility of mathematical model theory and finite element simulation is verified by calibration experiment.

scholarly journals A New Appliance for Improving the Miniscrew Stability

2016 ◽  
Vol 2016 ◽  
pp. 1-6
Author(s):  
Nurhat Ozkalayci ◽  
Mehmet Yetmez
Keyword(s):  
Finite Element ◽  
Stability Analysis ◽  
Primary Stability ◽  
Position Angle ◽  
Cortical Layer ◽  
Finite Element Models ◽  
Constant Force ◽  
The Stability

The aim of this study is to present a new appliance called stability leg designed as an additional anchorage providing device for increasing primary stability of orthodontic miniscrew. For this purpose, two finite element models (FEMs) with two different cortical layer thicknesses of 1 mm and 2 mm are considered. In order to achieve the stability analysis, these two main models, namely, Model I and Model II, are divided into subgroups according to stability leg lengths. Two types of forces are considered. (1) First force is a constant force of 1 N which is applied to all two models. (2) Second force is defined in the range of 1–4 N. Each of 1, 2.5, and 4 N of the second force is applied with a position angle ranging from 34° to 44°. Results show that stability of a miniscrew with 5 mm leg increases primary stability of the miniscrew.

The Modeling of Electromagnetic Linear Actuator for Vehicle Active Suspension System

2010 ◽  
Vol 40-41 ◽  
pp. 127-132
Author(s):  
Zhao Xiang Deng ◽  
Fei Lai
Keyword(s):  
Finite Element ◽  
Mathematic Model ◽  
Active Suspension ◽  
Element Model ◽  
Suspension System ◽  
Linear Actuator ◽  
Analysis Tool ◽  
Element Analysis ◽  
Simulation Results ◽  
Electromagnetic Linear Actuator

A new type of electromagnetic linear actuator for vehicle active suspension system is designed. Combined with the finite element analysis tool and electromagnetic induction principle, the finite element model and mathematic model are built up individually. Based on the simulation results, a prototype of electromagnetic linear actuator is developed. By comparison of the finite element simulation results and the experimental data, it shows the correctness of actuator design and simulation model.

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