scholarly journals Research on the Mechanical Properties of “Z” Type Double-Decker Ball Bearings

2013 ◽  
Vol 136 (1) ◽  
Author(s):  
Chengtao Yu ◽  
Longxiang Xu ◽  
Xudong Yu
Keyword(s):  
Contact Angle ◽  
Carrying Capacity ◽  
High Speed ◽  
Static Load ◽  
Radial Deformation ◽  
Load Carrying Capacity ◽  
Heavy Load ◽  
Double Decker ◽  
Load Carrying ◽  
Simulation Results

The mechanical model of a “Z” type double-decker ball bearing under the action of radial load is established in this paper on the basis of the Hertz contact theory. According to the security contact angle theory, the influences of inner and outer bearings' internal clearances on the bearing's static load carrying capacity, radial deformation, radial stiffness, and load distribution of balls are analyzed. This model is verified in both stationary and rotational loading experiments. Moreover, the simulation results show that the static load carrying capacity of Z type bearing is smaller than that of either inner bearing or outer bearing that is contributed to compose the Z type bearing. The static load carrying capacity of a Z type bearing reduces with the increase of the inner and outer bearings' internal clearance. These simulation results also indicate that the contact angle of the maximum loaded ball in the outer bearing easily exceeds its security contact angle compared with the inner bearing, which, as the main factor, may cause the Z type bearing to overload and to fail. In this sense, the investigated Z type bearings are unfit to apply to situations with heavy load, high speed, or high precision.

scholarly journals The static load carrying capacity of a corner joint of concrete filled circular steel column.

2002 ◽  
pp. 13-27 ◽  
Author(s):  
Noriyuki HORICHI ◽  
Tetsuya HOSAKA ◽  
Teruhiko YODA ◽  
Shinichi KATSUO
Keyword(s):  
Carrying Capacity ◽  
Static Load ◽  
Load Carrying Capacity ◽  
Load Carrying ◽  
Steel Column

The Granular Lubricated Journal Bearing: Evidence of Lift Formation

2019 ◽  
Vol 141 (4) ◽  
Author(s):  
Venkata K. Jasti ◽  
Martin C. Marinack ◽  
Deepak Patil ◽  
C. Fred Higgs
Keyword(s):  
Carrying Capacity ◽  
Granular Flow ◽  
High Speed ◽  
Journal Bearing ◽  
Hydrodynamic Lubrication ◽  
Flow Behavior ◽  
Extreme Environments ◽  
Granular Flows ◽  
Load Carrying Capacity ◽  
Load Carrying

This work demonstrates that granular flows (i.e., macroscale, noncohesive spheres) entrained into an eccentrically converging gap can indeed actually exhibit lubrication behavior as prior models postulated. The physics of hydrodynamic lubrication is quite well understood and liquid lubricants perform well for conventional applications. Unfortunately, in certain cases such as high-speed and high-temperature environments, liquid lubricants break down making it impossible to establish a stable liquid film. Therefore, it has been previously proposed that granular media in sliding convergent interfaces can generate load carrying capacity, and thus, granular flow lubrication. It is a possible alternative lubrication mechanism that researchers have been exploring for extreme environments, or wheel-regolith traction, or for elucidating the spreadability of additive manufacturing materials. While the load carrying capacity of granular flows has been previously demonstrated, this work attempts to more directly uncover the hydrodynamic-like granular flow behavior in an experimental journal bearing configuration. An enlarged granular lubricated journal bearing (GLJB) setup has been developed and demonstrated. The setup was made transparent in order to visualize and video capture the granular collision activity at high resolution. In addition, a computational image processing program has been developed to process the resulting images and to noninvasively track the “lift” generated by granular flow during the journal bearing operation. The results of the lift caused by granular flow as a function of journal rotation rate are presented as well.

Influence of geometric parameters on the bump foil bearing performance

2019 ◽  
Vol 234 (7) ◽  
pp. 1017-1026
Author(s):  
Sadanand Kulkarni ◽  
Soumendu Jana
Keyword(s):  
Carrying Capacity ◽  
High Speed ◽  
System Development ◽  
Load Capacity ◽  
Radial Clearance ◽  
Load Carrying Capacity ◽  
Foil Bearings ◽  
Foil Bearing ◽  
Load Carrying ◽  
Lift Off

High-speed rotating system development has drawn considerable attention of the researchers, in the recent past. Foil bearings are one of the major contenders for such applications, particularly for high speed and low load rotating systems. In foil bearings, process fluid or air is used as the working medium and no additional lubricant is required. It is known from the published literature that the load capacity of foil bearings depend on the operating speed, viscosity of the medium, clearance, and stiffness of the foil apart from the geometric dimensions of the bearing. In case of foil bearing with given dimensions, clearance governs the magnitude of pressure developed, whereas stiffness dictates the change in radial clearance under the generated pressure. This article deals with the effect of stiffness, clearance, and its interaction on the bump foil bearings load-carrying capacity. For this study, four sets of foil bearings of the same geometry with two levels of stiffness and clearance values are fabricated. Experiments are carried out following two factor-two level factorial design approach under constant load and in each case, the lift-off speed is measured. The experimental output is analyzed using statistical techniques to evaluate the influence of parameters under consideration. The results indicate that clearance has the maximum influence on the lift-off speed/ load-carrying capacity, followed by interaction effect and stiffness. A regression model is developed based on the experimental values and model is validated using error analysis technique.

Investigation on the Post-Ultimate Strength Behaviour of Sandwich Plate

2014 ◽  
Author(s):  
Wei Wang ◽  
Weijun Xu ◽  
Xiongliang Yao ◽  
Nana Yang
Keyword(s):  
Ultimate Strength ◽  
Carrying Capacity ◽  
Failure Modes ◽  
Sandwich Plate ◽  
Experimental Results ◽  
Sandwich Plates ◽  
Load Carrying Capacity ◽  
Load Carrying ◽  
Strength Behavior ◽  
Simulation Results

This paper focuses on the post-ultimate strength behavior of sandwich plates. With widely application of the laminate on the ship and offshore structures, the post-ultimate strength behavior is becoming more important for safety evaluation of structures. Since the post-ultimate strength behavior can reflect the collapse extent of sandwich plate when subjected to extreme loads. A sandwich plate was modeled by FEM, its load-displacement relationship was obtained and its collapse characteristics were analyzed. The load-displacement relationship indicates its post-ultimate strength behavior, which is shown as that the load carrying capacity has a rapidly reduction when the ultimate strength is exceeded, and that the failure modes of the sandwich plate are determined by the parameter of individual layer. The simulation results were validated against experimental results. Conclusions are drawn: the displacement of sandwich plate under axial compression increased slowly before reaching the ultimate strength, once the ultimate strength was exceeded, the loads exerted on the structures sharply decreased with slowly increased displacement until the plate cracked. The simulation results have a good agreement with the experimental results. The mainly failure modes of sandwich plates can be interpreted as delamination between skin & core and core compression fracture, which are typical failure modes in engineering. The stiffness of sandwich structures decreased due to the interlaminar cracking or skin fracture, further the load carrying capacity decreased, which is of significance for guiding the design of sandwich structures.

scholarly journals Contact Analysis and Static Load Carrying Capacity of Planetary Roller Screw Mechanism

2020 ◽  
Author(s):  
Nam Su Kim ◽  
Kyongho Kim ◽  
Sinhyok Jong
Keyword(s):  
Finite Element ◽  
Contact Stress ◽  
Carrying Capacity ◽  
Static Load ◽  
Load Capacity ◽  
Load Carrying Capacity ◽  
Elastic Plastic ◽  
Load Carrying ◽  
Roller Screw ◽  
Screw Mechanism

Abstract This paper aims to investigate the contact characteristics and static load carrying capacity of planetary roller screw mechanism (PRSM). Compared to the ball screw mechanism, the advantages of the PRSM are high stiffness, high load capacity, long travel life and compact structure, etc., since the PRSM possesses more contact points than ball screws in a comparable size. The actuated load is carried through the threaded surface contacts of the screw, the rollers and the nut and the contact characteristics of these components are very important for studying the wear, transmission accuracy and efficiency of a PRSM. Prior work has neglected to take a fundamental approach towards understanding the elastic-plastic contact characteristics of threaded surfaces under high loads and it is closely related to the static load carrying capacity of PRSM. Accordingly, in this paper, the contact characteristics of PRSM under the different working loads are modeled based on Hertz contact theory and the calculation formulas between normal force of thread turns and the elastic-plastic contact stress and deformation are derived. Then, it goes further to derive a calculation method of static load carrying capacity of PRSM based on simplified model of static load distribution. Finally, a verification model is developed by finite element method (FEM) to perform contact stress and strain analysis of PRSM. Besides, through the comparison of the results between the theory model and ANSYS Workbench finite element model verify the reliability of the theory.

scholarly journals Technological increase of static load carrying capacity of local raceways in ball bearings through ball rolling-off

2018 ◽  
Vol 2018 (12) ◽  
pp. 28-32
Author(s):  
Альберт Королев ◽  
Albert Korolev ◽  
Михаил Захарченко ◽  
Mihail Zakharchenko ◽  
Кристина Мищенко ◽  
...  
Keyword(s):  
Carrying Capacity ◽  
Ball Bearing ◽  
Static Load ◽  
Ball Bearings ◽  
Load Carrying Capacity ◽  
Combined Load ◽  
Ball Rolling ◽  
Load Carrying ◽  
Bearing Rings ◽  
External Loads

The paper reports the consideration of the ball rolling-off mechanism of ball bearing rings. The regularities of the distribution of external combined load between balls are defined. There is offered a simulator of a rolling-ff process allowing the ratio definition between a load upon balls and acting factor including the angle of balls contact with a race and a correlation of a radial and axial external loads.

Sign in / Sign up

Export Citation Format

Share Document