scholarly journals A Vibration Model of Ball Bearings with a Localized Defect Based on the Hertzian Contact Stress Distribution

2018 ◽  
Vol 2018 ◽  
pp. 1-14 ◽  
Author(s):  
Fanzhao Kong ◽  
Wentao Huang ◽  
Yunchuan Jiang ◽  
Weijie Wang ◽  
Xuezeng Zhao

To study the vibration mechanism of ball bearings with localized defects, a vibration model of a ball bearing based on the Hertzian contact stress distribution is proposed to predict the contact force and vibration response caused by a localized defect. The calculation of the ball-raceway contact force when the ball passes over the defect is key to establishing a defect vibration model. Hertzian contact theory indicates that the contact area between the ball and the raceway is an elliptical contact surface; therefore, a new approach is used to calculate the ball-raceway contact force in the defect area based on the stress distribution and the contact area. The relative motion between the inner ring, the outer ring, and the balls is considered in the proposed model, and the Runge-Kutta algorithm is used to solve the vibration equations. In addition, vibration experiments of a bearing with an outer ring defect under different loads are performed. The numerical signals and experimental signals are compared in the time and frequency domains, and good correspondence between the numerical and experimental results is observed. Comparisons between the traditional model and the proposed model reveal that the proposed model provides more reasonable results.

Author(s):  
Sherif Mohareb ◽  
Arndt Goldack ◽  
Mike Schlaich

Cable-stayed and extra-dosed bridges are today widely used bridge types. Recently, saddles have been used to deviate strands of cables in the pylons. Up to now the mechanics of strands on saddles are not well understood. It was found, that typical longitudinal contact stress distributions between strand and saddle show a strong nonlinearity and a high peak value around the detachment point, where the strand meets the saddle. This paper presents a procedure to analyse the longitudinal contact stress distribution obtained by FEM calculations: This contact stress can be idealised as a constant contact stress according to the Barlow's formula and a contact force at the detachment point due to the flexural rigidity of the bent tension elements. An analytical model is provided to verify this contact force. Finally, a formula is presented to calculate the maximum contact stress. This study provides the basis for further research on saddle design and fatigue of strands.


2012 ◽  
Vol 236-237 ◽  
pp. 422-427
Author(s):  
Xue Mei Liu ◽  
Jian Wei Luo ◽  
Ai Ping Li

This study was undertaken to analytically investigate factors which influence the performance of the HSK toolholder-spindle connection. The change of contact area and the contact stress distribution of HSK-A63 toolholder-spindle interface were analyzed with the finite element software ANSYS. The analysis results showed that the contact area and contact stress are significantly affected by clamping force and spindle speed, and that enough magnitude of interference can offset the gap between spindle and toolholder under high rotational speed and also affect the clamping force assigned to the flange face.


2011 ◽  
Vol 211-212 ◽  
pp. 535-539
Author(s):  
Ai Hua Liao

The impeller mounted onto the compressor shaft assembly via interference fit is one of the key components of a centrifugal compressor stage. A suitable fit tolerance needs to be considered in the structural design. A locomotive-type turbocharger compressor with 24 blades under combined centrifugal and interference-fit loading was considered in the numerical analysis. The FE parametric quadratic programming (PQP) method which was developed based on the parametric variational principle (PVP) was used for the analysis of stress distribution of 3D elastoplastic frictional contact of impeller-shaft sleeve-shaft. The solution of elastoplastic frictional contact problems belongs to the unspecified boundary problems where the interaction between two kinds of nonlinearities should occur. The effect of fit tolerance, rotational speed and the contact stress distribution on the contact stress was discussed in detail in the numerical computation. The study play a referenced role in deciding the proper fit tolerance and improving design and manufacturing technology of compressor impellers.


Author(s):  
J. Groenendijk ◽  
C. H. Vogelzang ◽  
A. A. A. Molenaar ◽  
B. R. Mante ◽  
L. J. M. Dohmen

The relative strain effects of 15 different load configurations were studied. Using the linear tracking device (LINTRACK) accelerated loading facility, two 5-year-old pavements of 0.15-m asphalt on sand (one virgin and one loaded with 4 million 75-kN wheel loads) were tested. All measured strains were converted to strain factors relative to a standard load (super-single tire, 50 kN, 0.70 MPa). The results were compared with earlier measurements and BISAR-calculated factors. The results on the loaded pavement showed markedly more variation than those on the unloaded pavement. Generally, the BISAR-calculated relative strain factors matched the measured values well for the super-single tire. Considerable difference occurred only in the most extreme load conditions. Nonuniform contact stress distribution can be the cause for this. The calculated relative strain factors for the dual tire configurations underestimated the measured values.


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