roller bearing
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2022 ◽  
Vol 36 (06) ◽  
Author(s):  
HUNGLINH AO ◽  
THANHHANG NGUYEN ◽  
V.HO HUU ◽  
TRANGTHAO NGUYEN

SVM parameters have serious effects on the accuracy rate of classification result. Tuning SVM parameters is always a challenge for scientists. In this paper, a SVM parameter optimization method based on Adaptive Elitist Differential Evolution (AeDE-SVM) is proposed. Furthermore, AeDE-SVM is applied to diagnose roller bearing fault by using complementary ensemble empirical mode decomposition (CEEMD) and singular value decomposition (SVD) techniques. First, original acceleration vibration signals are decomposed into Intrinsic Mode Function (IMFs) by using CEEMD method. Second, initial feature matrices are extracted from (IMFs) by singular value decomposition (SVD) techniques to obtain single values. Third, these values serve as input vector for AeDE-SVM classifier. The results show that the combination of AeDE-SVM classifiers and the CEEMD-SVD method obtains higher classification accuracy and lower cost time compared to other methods. In this paper, the roller bearing vibration signals were used to evaluate the proposed method. The experimental results showed that the superior performance compared to other SVM parameter optimization techniques and successfully recognized different fault types of roller bearing during its operation.


2022 ◽  
Vol 8 (2) ◽  
pp. 316-319
Author(s):  
Jusnita

  Roller Rocker Arm is important for transmitting signals and determining work efficiency which is the result of technological developments from ordinary rocker arms. The purpose of this study was to compare the use of conventional rocker arm with rocker arm roller on power, torque, exhaust emissions, compression on a motorcycle engine. The research method used is changing the fuel system, ignition system, changing the valve mechanism. The maximum torque on the conventional rocker arm occurs at 2995 rpm with a value of 10.92 Nm. Maximum torque decreases with increasing engine speed. The decrease in power at high speed occurs due to the influence of the volume of the fuel and air mixture which tends to decrease. The highest fuel consumption occurs at 7000 rpm engine speed in a conventional rocker arm of 0.124 kg/kWh, so the rocker arm roller is more efficient than the conventional rocker arm. Fuel consumption rocker arm roller rotation 7000 rpm 0.028 kg/kWh. While the conventional rocker arm fuel consumption at 7000 rpm 0.124 kg/kWh. Exhaust emissions, the rocker arm roller is environmentally friendly compared to the conventional rocker arm CO2 rocker arm roller only produces 5.2%, while the conventional rocker arm test results after the average CO2 value reaches 5.3%. The results of testing the two rocker arms on compression are the same at 90 Psi and 6.2kg/ from the standard size of 10-11kg/  


Materials ◽  
2021 ◽  
Vol 15 (1) ◽  
pp. 196
Author(s):  
Paweł J. Romanowicz ◽  
Dariusz Smolarski ◽  
Marek S. Kozień

A new approach based on the direct spectral method for fatigue analysis of elements subjected to bimodal stress histories, including high compression effects, is proposed. A correction factor, taking into account the influence of the mean compressive stresses, is used in the proposed method. Equivalent amplitude is estimated, based on criteria proposed by Smith, Watson, and Tooper, and by Bergmann and Seeger. The method is presented with example of a thrust roller bearing. Two cases in which the rollers were subjected to constant force 206 N (where constant amplitude stresses occurred in the rollers) and cyclic force (where bimodal stresses with variable amplitudes occurred in the rollers) are studied. It is observed that multiaxial fatigue criteria (Crossland, Papadopoulos) do not include the influence of bimodal stresses and should not be used for such loading conditions. The proposed method includes both kinds of stress waveforms in the fatigue analysis and can be applied for the accurate identification of stress components and the determination of fatigue life. The damage rate calculated by the proposed approach for rollers subjected to a cyclic force (equivalent load equal to 151 N) was 0.86, which is in good agreement with the recommendations provided in the literature. The obtained accuracy of the proposed method is above 95%.


Sensors ◽  
2021 ◽  
Vol 22 (1) ◽  
pp. 195
Author(s):  
Qinghua Wang ◽  
Lijuan Wang ◽  
Hongtao Yu ◽  
Dong Wang ◽  
Asoke K. Nandi

In view of the fact that vibration signals of rolling bearings are much contaminated by noise in the early failure period, this paper presents a new denoising SVD-VMD method by combining singular value decomposition (SVD) and variational mode decomposition (VMD). SVD is used to determine the structure of the underlying model, which is referred to as signal and noise subspaces, and VMD is used to decompose the original signal into several band-limited modes. Then the effective components are selected from these modes to reconstruct the denoised signal according to the difference spectrum (DS) of singular values and kurtosis values. Simulated signals and experimental signals of roller bearing faults have been analyzed using this proposed method and compared with SVD-DS. The results demonstrate that the proposed method can effectively retain the useful signals and denoise the bearing signals in extremely noisy backgrounds.


Author(s):  
Shuai Li ◽  
Farshad Hedayati Dezfuli ◽  
M. Shahria Alam ◽  
Jingquan wang

Abstract In this study, a new type of seismic isolation device, called SMA wire-based roller bearing (SMA-RB) is developed and introduced. The SMA-RB has been designed, manufactured, and experimentally tested. This bearing consists of cylindrical roller bearings and SMA wires with straight or cross configurations, as supplementary damping elements. In such a smart bearing, the superelastic SMA wires are passed through the hooks/pulleys attached to the supporting plates of the bearings in different configurations. The rollers provide lateral flexibility, and SMA wires supply energy dissipation and self-centering properties. In the manufacturing stage, a new mechanism for coupling wires (i.e. SMA wire joiner/coupler) is proposed. The results show that SMA wires, made of Nickle Titanium (NiTi), provide a self-centered damping mechanism with almost zero residual deformation which can effectively control the device from over-displacement. While using pulleys and newly designed wire joiners in the SMA-RB, the bearing can experience a stable cyclic behavior. Since the rollers generate a negligible amount of frictional force, the superelastic NiTi wires with a flag-shaped hysteresis mainly contribute to the overall shear hysteretic response of the SMA-RB. A triangular-shaped constitutive model can be used to accurately describe the hysteretic behavior of SMA-RB with different wire configurations.


2021 ◽  
pp. 1-23
Author(s):  
Abbas shafiee ◽  
Thomas Russell ◽  
Farshid Sadeghi ◽  
Matthew Wilmer

Abstract The objective of this investigation was to analytically investigate the performance of a spherical roller bearing operating under various loading and speed combinations. In order to achieve the objective, a full six degree of freedom spherical roller bearing dynamic model was developed. The model was corroborated with results in open literature. An adaptive slicing method was developed to optimize the accuracy and computational effort of the roller force, skew, and tilt calculations. A comprehensive roller-race contact analysis in terms of slip velocity and contact area was then carried out to identify how bearing load and inner race speed variations change slip velocity and skew at the roller-race contact. The results from this investigation demonstrate that roller skew increases with inner race speed, while the roller tilt remains relatively constant. The inner race speed and roller slip velocity correlate well, which causes the traction force to increase and therefore produce greater skew. Skew and tilt angles also increase with applied axial load. However, at a certain load the skew angle begins to decrease.


2021 ◽  
Vol 68 (5) ◽  
pp. 14-23
Author(s):  
Andreas Winkler ◽  
Marcel Bartz ◽  
Sandro Wartzack

This contribution presents an approach for the numerical wear calculation of rolling/sliding-contacts. The finite element method based simulation model of Winkler [1] is extended to include contacts subject to boundary lubrication in addition to contacts subject to mixed lubrication. Using the example of an axial cylindrical roller bearing and two load cases, wear-modeling results of the mixed and boundary lubrication regime are illustrated.


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