The onset condition of friction noise in ball joint under concentric loading

2015 ◽  
Vol 89 ◽  
pp. 57-61 ◽  
Author(s):  
Jaeyoung Kang
2020 ◽  
pp. 60-68
Author(s):  
V. A. Pyalchenkov ◽  
D. V. Pyalchenkov

Research has found that the axial load applied to the bit is distributed unevenly along the crowns of the balls. The middle crowns are the busiest. The value of the axial force perceived by a separate ring is associated with the deformation of the details of the ball joint. You can reduce the uneven loading of crowns by shifting them along the ball along the radius of the bit, placing them so that the vertical line passing through the center of the lower ball of the lock bearing passes through the middle of the gap between the crowns of neighboring balls. The bits with the new option of placing the teeth on the balls were tested on the stand and in industrial conditions. For the bits of this design, the axial load was distributed more evenly over the crowns, which allowed increasing the efficiency of their work.


Friction ◽  
2021 ◽  
Author(s):  
Kevin Lontin ◽  
Muhammad Khan

AbstractPhenomena of friction, wear, and noise in mechanical contacts are particularly important in the field of tribomechanics but equally complex if one wants to represent their exact relationship with mathematical models. Efforts have been made to describe these phenomena with different approaches in past. These efforts have been compiled in different reviews but most of them treated friction, wear mechanics, and acoustic noise separately. However, an in-depth review that provides a critical analysis on their interdependencies is still missing. In this review paper, the interdependencies of friction, wear, and noise are analysed in the mechanical contacts at asperitical level. The origin of frictional noise, its dependencies on contact’s mechanical properties, and its performance under different wear conditions are critically reviewed. A discussion on the existing mathematical models of friction and wear is also provided in the last section that leads to uncover the gap in the existing literature. This review concludes that still a comprehensive analytical modelling approach is required to relate the interdependencies of friction, noise, and wear with mathematical expressions.


2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Markus Greinwald ◽  
Emily K. Bliven ◽  
Alex Trompeter ◽  
Peter Augat

Abstract Hexapod-ring-fixators have a characteristic rattling sound during load changes due to play in the hexapod struts. This play is perceived as unpleasant by patients and can lead to frame instability. Using slotted-ball-instead of universal-joints for the ring-strut connection could potentially resolve this problem. The purpose of the study was to clarify if the use of slotted-ball-joints reduces play and also fracture gap movement. A hexapod-fixator with slotted-ball-joints and aluminum struts (Ball-Al) was compared to universal-joint-fixators with either aluminum (Uni Al) or steel struts (Uni Steel). Six fixator frames each were loaded in tension, compression, torsion, bending and shear and mechanical performance was analyzed in terms of movement, stiffness and play. The slotted-ball-joint fixator was the only system without measurable axial play (<0.01 mm) compared to Uni-Al (1.2 ± 0.1) mm and Uni-Steel (0.6 ± 0.2) mm (p≤0.001). In both shear directions the Uni-Al had the largest play (p≤0.014). The resulting axial fracture gap movements were similar for the two aluminum frames and up to 25% smaller for the steel frame, mainly due to the highest stiffness found for the Uni-Steel in all loading scenarios (p≤0.036). However, the Uni-Steel construct was also up to 29% (450 g) heavier and had fewer usable mounting holes. In conclusion, the slotted-ball-joints of the Ball-Al fixator reduced play and minimized shear movement in the fracture while maintaining low weight of the construct. The heavier and stiffer Uni-Steel fixator compensates for existing play with a higher overall stiffness.


2013 ◽  
Vol 16 (10) ◽  
pp. 1749-1761 ◽  
Author(s):  
Xiaodun Wang ◽  
Kai Weng ◽  
Hongbo Liu ◽  
Yulan Zhang ◽  
Zhihua Chen

2011 ◽  
Vol 330 (22) ◽  
pp. 5490-5499 ◽  
Author(s):  
Jaeyoung Kang
Keyword(s):  

1992 ◽  
Vol 114 (3) ◽  
pp. 205-211 ◽  
Author(s):  
A. Ertas ◽  
G. Mustafa ◽  
O. Cuvalci

It is well known that the upper ball joint in a marine riser, in deep drilling, can cause fatigue damage in the drill pipe passing through it. A study of fracture mechanics and S–N curve approaches has been undertaken to determine the dynamic fatigue damage in the drill pipe. Miner’s rule is utilized in both methods to determine the total damage. The results of both methods are compared.


1994 ◽  
Vol 116 (2) ◽  
pp. 338-344 ◽  
Author(s):  
Sourav K. Bhunia ◽  
John H. Lienhard

In turbulent liquid jet impingement, a spray of droplets often breaks off of the liquid layer formed on the target. This splattering of liquid alters the efficiencies of jet impingement heat transfer processes and chemical containment safety devices, and leads to problems of aerosol formation in jet impingement cleaning processes. In this paper, we present a more complete study of splattering and improved correlations that extend and supersede our previous reports on this topic. We report experimental results on the amount of splattering for jets of water, isopropanol-water solutions, and soap-water mixtures. Jets were produced by straight tube nozzles of diameter 0.8–5.8 mm, with fully developed turbulent pipe-flow upstream of the nozzle exit. These experiments cover Weber numbers between 130-31,000, Reynolds numbers between 2700-98,000, and nozzle-to-target separations of 0.2 ≤ l/d ≤ 125. Splattering of up to 75 percent of the incoming jet liquid is observed. The results show that only the Weber number and l/d affect the fraction of jet liquid splattered. The presence of surfactants does not alter the splattering. A new correlation for the onset condition for splattering is given. In addition, we establish the range of applicability of the model of Lienhard et al. (1992) and we provide a more accurate set of coefficients for their correlation.


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