scholarly journals Investigation on Modeling and Formation Mechanism of Dynamic Rotational Error for Spindle-Rolling Bearing System

2020 ◽  
Vol 10 (17) ◽  
pp. 5753
Author(s):  
Gaofeng Hu ◽  
Ye Chen ◽  
Liangyu Cui ◽  
Gang Jin ◽  
Tingjian Wang ◽  
...  
Keyword(s):  
Rolling Bearing ◽  
Modeling Method ◽  
Machining Accuracy ◽  
Surface Waviness ◽  
Rotational Error ◽  
Bearing Raceway ◽  
Series Of Experiments ◽  
Contour Accuracy ◽  
Development Phases ◽  
Good Agreement

In the field of precision machining, the spindle-rolling bearing (SRB) system is widely used on the machine tool as one of the most fundamental and important components. The rotational error motions of the SRB system have significant effects on the machining accuracy (contour accuracy and surface roughness). Over the past decades, much work has been focused on the measurement of spindle balancing and rotational error motions, the vibrations response induced by the nonlinear stiffness and surface waviness of the bearing. However, the formative mechanism of the rotational error motions for the SRB system is not well understood. In this paper, the dynamic model of the SRB system considering the bearing nonlinearity is established. Seeking to reveal the effects of surface waviness of the bearing raceway, unbalance mass and disturbance force on the dynamic rotational error, the modeling method and formative mechanism of the dynamic rotational error for the SRB system is explored both theoretically and experimentally. Then, numerical simulation is performed to analyze the influence of the bearing raceway waviness, unbalance mass and disturbance force on the dynamic rotational error. An experimental setup is established based on a typical SRB system and a series of experiments are carried out. The experimental results are in good agreement with the theoretical and simulation results, which can demonstrate the feasibility and validity of the modeling method. Furthermore, this method can be effectively applied to the design and development phases of an SRB system to improve dynamic rotational accuracy.

Noise calculation method of deep groove ball bearing caused by vibration of rolling elements considering raceway waviness

2021 ◽  
pp. 095440622110458
Author(s):  
Minjie Sun ◽  
Haojie Xu ◽  
Qi An
Keyword(s):  
Ball Bearing ◽  
Axial Direction ◽  
Rolling Bearing ◽  
Mechanical Analysis ◽  
Machining Accuracy ◽  
Surface Waviness ◽  
Random Surface ◽  
Deep Groove ◽  
Deep Groove Ball Bearing ◽  
Rolling Elements

Raceway waviness error is the main reason to cause rolling elements to vibrate along axial direction and emit noise. In this paper, the mechanical analysis on deep groove ball bearing is carried out. With auto-correlation function, random surface waviness of both inner and outer raceways is simulated. A contact model of rolling elements and raceways considering surface waviness is established. Combining with the theory of acoustic equation, a calculation model is established for the noise caused by vibration of rolling elements and inner ring. The results show that with the decrease of machining accuracy, the noise of rolling elements increases due to axial vibration; with the increase of rotation speed, the noise also increases. Besides, the spectrum of radiation noise of inner raceway with different waviness amplitudes is given. The results indicate that the 3-D waviness on raceway surface has an influence on the vibration and the noise emitted by both rolling elements and inner ring, and provide guidance for sound control in deep groove rolling bearing.

Predicting the surface waviness of sheet moulding compound parts by simulating process-induced thermal stresses

2011 ◽  
Vol 31 (8-9) ◽  
Author(s):  
Walter Michaeli ◽  
Christoph Kremer
Keyword(s):  
Thermal Stresses ◽  
Surface Defects ◽  
Computation Method ◽  
Surface Waviness ◽  
Curing Reaction ◽  
Calculated Stress ◽  
Moulding Compound ◽  
Different Types ◽  
Sheet Moulding Compound ◽  
Good Agreement

Abstract This paper describes an opportunity to compute the surface waviness of compression moulded sheet moulding compound (SMC) parts by simulating residual stresses. First, different types of surface defects occurring on SMC parts are discussed. A method for calculating the surface waviness of the compression moulded part is presented, which combines the simulation of the production process and the structural computation. Modelling of the curing reaction and the development of mechanical properties are discussed and implemented. The potential of the computation method is shown for an automotive fender made of SMC. The results state that the curing reaction of SMC can be well described using the approach of Ng and Manas-Zloczower. The position of the measured waviness on the examined fender is in good agreement with the calculated stress distribution.

Scattering Tomography and Its Application to Sooting Diffusion Flames

1994 ◽  
Vol 116 (1) ◽  
pp. 144-151 ◽  
Author(s):  
M. P. Mengu¨c¸ ◽  
P. Dutta
Keyword(s):  
Diffusion Flames ◽  
Tomographic Reconstruction ◽  
Scattering Coefficient ◽  
Reconstruction Technique ◽  
Transmission Tomography ◽  
Ion Laser ◽  
Series Of Experiments ◽  
Argon Ion ◽  
Good Agreement

A new analytical tomographic reconstruction technique was developed for the determination of the extinction and scattering coefficient distributions in axisymmetric media. This method, called “scattering tomography,” was tested for several particle concentration profiles corresponding to those for diffusion flames. After that, a series of experiments were performed on sooting acetylene flames using an argon-ion laser nephelometer. The experimental results were reduced using both the transmission and scattering tomography techniques to obtain the extinction coefficient profiles. It was shown that in the center of the flame, the results from these two approaches were in good agreement. Scattering tomography can be used to determine both the absorption and scattering coefficient distributions in the medium. In addition to that, it is preferable over the transmission tomography if the medium is optically very thin and particles are predominantly scattering.

Experiments on the diffraction of weak blast waves: the von Neumann paradox

1980 ◽  
Vol 369 (1739) ◽  
pp. 537-555 ◽  
Keyword(s):  
Strong Shock ◽  
Weak Shock ◽  
Blast Waves ◽  
Shock Diffraction ◽  
Self Similarity ◽  
Von Neumann ◽  
Shock System ◽  
Series Of Experiments ◽  
Mach Reflexion ◽  
Good Agreement

This paper presents the results of our experiments with weak incident shocks diffracting over concave corners. For Mach reflexion, the experiments reveal a fundamental difference between weak and strong shock diffraction, namely that for weak shock diffraction the corner signal can always catch up with the three-shock confluence, but this does not happen for strong shock diffraction except for comparatively small corner angles. We show that by taking into account the attenuating effect of the corner signal it is possible in principle to modify the well-known von Neumann theory and that this is then in good agreement with the experimental data. Evidence is presented which shows that another effect of the corner signal is to cause a partial loss of the self-similarity property of the three-shock system. Indeed, for one series of experiments the oncoming flow relative to the Mach stem behaved as though it were parallel to the sloping wall of the corner and therefore did not have the familiar radial distribution centred on the corner. The modified theory can be extended to include the persisted regular reflexion phenomenon suggesting that this is an unresolved Mach reflexion. In that event there is some experi­mental evidence that transition to Mach reflexion would then be consistent with the normal shock point as Henderson and Lozzi found for strong shock diffraction.

The Finishing of Rolling Bearing Raceway by Electrochemical Mechanical Finishing (ECMF) Technology

2011 ◽  
Vol 189-193 ◽  
pp. 842-846 ◽  
Author(s):  
Hui Wang ◽  
Hai Bin Li ◽  
Wen Cong Jiao ◽  
Jian Min Zuo
Keyword(s):  
Surface Roughness ◽  
Wave Velocity ◽  
Rolling Bearing ◽  
Electrochemical Process ◽  
Service Performance ◽  
Affecting Factors ◽  
Electrode Gap ◽  
Mechanical Process ◽  
Bearing Raceway ◽  
Rate Profile

This paper studies the technology of Electrochemical Mechanical Finishing (ECMF) on rolling bearing raceway. The principle of the technology is introduced, and the finishing results are presented. The results show that the surface roughness, supporting length rate, profile roundness, waveness and wave velocity are all improved greatly. Also, the main affecting factors such as the inter-electrode gap, electrochemical process and mechanical process are discussed in this paper. The bearings finished by ECMF have better service performance and life.

Identification of Natural Frequency of Bearing Rotor Based on GA-SVM

2012 ◽  
Vol 443-444 ◽  
pp. 27-33
Author(s):  
Tian Ran Ma ◽  
Fei Hu Qin ◽  
Rui Xue Liu ◽  
Feng Jie Zhang
Keyword(s):  
Experimental Data ◽  
Support Vector Machine ◽  
Natural Frequency ◽  
Rolling Bearing ◽  
Linear Mapping ◽  
Support Vector ◽  
Non Linear ◽  
Experimental Values ◽  
Rotor Structure ◽  
Good Agreement

During identify natural frequency of bearing rotor, due to the complex non-linear relationship among the factors which influence natural frequency, so it is hard to establish a complete and accurate theoretical model. Based on the generalization and approximation of non-linear mapping capability of support vector machine (SVM) and the powerful ability of global optimization of the genetic algorithm (GA), the paper through optimizing the SVM by GA, establishes combined Genetic Support Vector Machine (GA-SVM). The method establishes the mapping between the natural frequency of a rolling bearing rotor and the various parameters, which reduces the rotor structure for the study similar to the natural frequency of the calculation of the workload greatly. Using the model to indentify the natural frequency of bearing rotor under different parameters, then compare identification value with experimental values shows that projections in good agreement with the experimental data.

scholarly journals Added Mass and Damping of a Vibrating Rod in Confined Viscous Fluids

1976 ◽  
Vol 43 (2) ◽  
pp. 325-329 ◽  
Author(s):  
S. S. Chen ◽  
M. W. Wambsganss ◽  
J. A. Jendrzejczyk
Keyword(s):  
Experimental Data ◽  
Experimental Study ◽  
Cylindrical Shell ◽  
Closed Form Solution ◽  
Added Mass ◽  
Form Solution ◽  
Viscous Fluids ◽  
Series Of Experiments ◽  
Theoretical Results ◽  
Good Agreement

This paper presents an analytical and experimental study of a cylindrical rod vibrating in a viscous fluid enclosed by a rigid, concentric cylindrical shell. A closed-form solution for the added mass and damping coefficient is obtained and a series of experiments with cantilevered rods vibrating in various viscous fluids is performed. Experimental data and theoretical results are in good agreement.

scholarly journals Experimental Assessment of Influence of the Ball Bearing Raceway Curvature Ratio on the Level of Vibration

2020 ◽  
Vol 22 (4) ◽  
pp. 103-111 ◽  
Author(s):  
Pawel Zmarzly
Keyword(s):  
Experimental Studies ◽  
Rolling Bearing ◽  
Rolling Element Bearings ◽  
Test Results ◽  
Curvature Ratio ◽  
Rolling Element ◽  
Innovative System ◽  
Bearing Raceway ◽  
Bearing Rings ◽  
Car Transportation

Raceway curvature ratio is a very important parameter, because its values influence the performance characteristics of rolling-element bearings, their durability and the level of generated vibrations. However, the level of generated vibrations is one of the most important operating parameters of the rolling-element bearings. Excessive vibrations generated by rolling-element bearings affect the operation of the whole mechanism. The article presents experimental studies aimed at evaluation of influence of the inner and outer raceway curvature ratios of 6304-type rolling-element bearings on generated vibrations values. The raceway curvature ratio was determined based on results of metrological measurements. For this purpose, the radii of the inner and outer raceways as well as the diameters of the balls were measured. Design and principle of operation of an innovative system for analysis of the raceway geometry of the rolling bearing rings was presented. The vibration analysis was carried out in three frequency ranges, i.e. low (50-300 Hz), medium (300-1,800 Hz) and high (1,800-10,000 Hz). Values of measured vibrations were expressed in Anderon units. The test results showed that increase in the raceway curvature ratio causes a moderate decrease in the value of the generated vibrations. The research results presented in this article will serve as a guidance to designers and manufacturers of the rolling-element bearings on how to modify the geometry of raceways and balls to obtain bearings that generate low vibration values. That is very important in car transportation.

scholarly journals Comparison of Hydraulic Conductivity Values Obtained from Empirical Formulae and Laboratory Experiments

2020 ◽  
Vol 68 (4) ◽  
pp. 669-678
Author(s):  
Mario Hala ◽  
Lubomír Petrula ◽  
Zakaraya Alhasan
Keyword(s):  
Experimental Data ◽  
Hydraulic Conductivity ◽  
Laboratory Experiments ◽  
Internal Erosion ◽  
Variable Porosity ◽  
Groundwater Flow Regime ◽  
Series Of Experiments ◽  
Different Grain Size ◽  
Good Agreement

Hydraulic conductivity determination plays an essential role in the investigation of groundwater flow regime which can then influence many field problems such as pumping capabilities in the area, transport of contaminant or heat and soil internal erosion. Numerous equations based on dimensional analysis or experimental measurements have been published since the end of the 19th century for the determination of hydraulic conductivity. However, not all of these formulae are applicable for every material and all of them bring some uncertainty in the value of hydraulic conductivity. This paper contains a description of experimental research carried out concerning the determination of hydraulic conductivity for four types of sand with different grain size distribution curves and variable porosity. Obtained values of hydraulic conductivity ranged from 1 × 10-4 to 4 × 10-3 according to the sample porosity. The series of experiments consisted of 160 separate tests conducted in order to obtain relevant statistical sets. In this paper, the experimental data are discussed and compared with hydraulic conductivities obtained from 6 empirical formulae recommended in a previous study. The comparison showed that some empirical formulae provide a good agreement with the experimental data (the most precise were formulae published by Terzaghi and by Sauerbrey). However, some formulae showed high deviation from measured data (formula published by Zamarin).

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