Effect of off-sized balls on contact stresses in a touchdown bearing

Neisi, Neda; Sikanen, Eerik; Sopanen, Jussi

doi:10.1016/j.triboint.2017.12.036

Cited by 11 publications

(7 citation statements)

References 16 publications

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“…A model has been considered, taking into consideration the stiffness, damping, and friction between the bearing components. 16–18 The output of the model gave the contact deformations between the balls and bearing races, contact forces, and Hertzian contact stresses in each ball. The results show that off-sized balls alter the contact stiffness, contact force and stress concentration in mating bearing surfaces.…”

Section: Introductionmentioning

confidence: 99%

Experimental and numerical investigation of defect-size estimation in taper roller bearing

Nabhan

Rashed

2018

Noise & Vibration Worldwide

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In this article, the estimation of different defect sizes present on the outer race of taper roller bearing confirms the effectiveness of the applied method for different vibration signals. Experiments and numerical model conducted for three primary conditions of bearing setting, which are positive, negative, and zero clearance. The outer race is installed in five different positions so that the defect located at 0°, 45°, 90°, 135°, and 180°. The output of the numerical model finds close correlation with the vibration signal pattern-obtained experiments. From the results, it is clear that defect-size estimation is more precise when the defect is introduced in the unloading area, and the contact time depends directly on the size of the defect, through which it is easy to calculate its value of the defect.

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Section: Introductionmentioning

confidence: 99%

Experimental and numerical investigation of defect-size estimation in taper roller bearing

Nabhan

Rashed

2018

Noise & Vibration Worldwide

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“…They improved a quasi-static model of ball bearing considering the misalignment in its ring. Neisi et al worked on the effect of off-sized balls on contact stresses in a touchdown bearing [15]. Yi Qin et al developed a dynamics model for deep groove ball bearings with local faults based on coupled and segmented displacement excitation [16].…”

Section: Introductionmentioning

confidence: 99%

“…In case of rolling element bearings, the elastic deformation takes place at both the inner raceway and the outer raceway with the rolling element. Based on the Hertzian contact theory, the relation between load F and deflection is [15]:…”

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confidence: 99%

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Effect of Impeller Diameter on Dynamic Response of a Centrifugal Pump Rotor

et al. 2021

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This paper investigates the effect of impeller diameter on the dynamic response of a centrifugal pump using an inverse dynamic method. For this purpose, the equations of motion of the shaft and the impeller are derived based on Timoshenko beam theory considering the impeller as a concentrated mass disk. For practical modeling, the model of Jones and Harris is added to the equation to include the effect of bearings. As a case study, the model is applied to a process pump used in an oil refinery. Computing the eigenvalues of the model and comparing them with the natural frequencies of the structure, the model updating of the problem is performed through an indirect method. Three impellers with different diameters are applied to the updated model. The results show that increasing the diameter of the pump impeller can increase the amplitude of vibration up to 52% at critical speeds of the rotor. It is found that in addition to the hydraulic condition and efficiency, the impeller diameter should be considered as an important factor in the selection of centrifugal pumps.

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“…The experimental setup enabled them to investigate the variation of temperature under different speeds and operating conditions. The touchdown bearings utilized in an AMB supported rotor differ from the conventional rotor bearing system and the differences have been demonstrated in paper by Neisi et al [20]. Due to the complicated geometry of the bearing assembly and the change in the heat generation rate, some simplifications for the boundary conditions and the model might be required.…”

Section: Introductionmentioning

confidence: 99%

Influence of surface waviness in the heat generation and thermal expansion of the touchdown bearing

Neisi

Heikkinen

Sopanen

2019

European Journal of Mechanics - A/Solids

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In an active magnetic bearings (AMBs) supported rotor system, the touchdown bearings have been proposed to support the rotor during an electromagnetic field shortage. The heat generation due to the high impact and collision of the rotor and touchdown bearing, in addition to the internal friction in the bearing, raises the temperature of the touchdown bearing. In this work, a numerical model is applied to simulate the rotor dropdown where the FEmodel of the rotor is integrated with the dynamic and thermal model of the touchdown bearing. The rotor that is used as a case study is supported by a deep groove ball bearing and a pair of angular contact ball bearings installed in an X-configuration. The present study focuses on evaluating different orders of surface waviness in a pair of angular contact ball bearings. The equivalent electrical circuit model is implemented for computing the thermal behavior of the touchdown bearing. Results indicated that the dynamic friction coefficient between the rotor and inner race has a considerable impact on bounce height and the whirling motion of the rotor. Furthermore, for a certain amplitude of surface waviness, the effect of various orders of waviness is investigated and it has been found that surface waviness of the bearing alters the contact force and friction loss in the touchdown bearing. In addition, the effect of a higher amplitude of surface waviness on thermal expansion of the touchdown bearing is studied.

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Effect of off-sized balls on contact stresses in a touchdown bearing

Cited by 11 publications

References 16 publications

Experimental and numerical investigation of defect-size estimation in taper roller bearing

Experimental and numerical investigation of defect-size estimation in taper roller bearing

Effect of Impeller Diameter on Dynamic Response of a Centrifugal Pump Rotor

Influence of surface waviness in the heat generation and thermal expansion of the touchdown bearing

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