Large Roller Bearings Research Articles

Fatigue methodology for life predictions for the wheel-rail contact area in large offshore turret bearings

The present report presents a fatigue life prediction method for large roller bearings applied in the turret turn table for large loading buoy units. The contact points between wheel and rail in these bearings are subjected to a multi-axial fluctuating stress situation and both surface wear and fatigue cracking may occur. A methodology based on the Dang Van fatigue criterion is adopted. The criterion is based on an equivalent stress defined as a combination of the fluctuation of the shear stress from its mean value at a critical plane and the associated hydrostatic stress at the given time. The present work is supporting the theoretical model by extensive laboratory testing. Both full scale testing of wheel on rail and small scale testing for characterizing the steel material are carried out. An experimental program was carried out with the high strength stainless steel S165M. The Dang Van stress concept is applied in combination with the Random Fatigue Limit Method (RFLM) for life data analyses. This approach gives the opportunity to include both finite lives and the run-outs in a rational manner without any presumption of the existence of a fatigue limit in advance of the data. This gives a non-linear S-N curve for a log-log scale in the very high cycle regime close to the fatigue limit. It is demonstrated how the scatter in fatigue limit decreases when the Dang Van stress concept is applied and that the fatigue limit is occurring beyond 107 cycles. KEYWORDS. Dang Van criterion; Random Fatigue Limit Method; Rolling Contact Fatigue.

Analysis of Tribological Processes in Components of Massive Roller Bearings

The paper presents an analysis of tribological processes on the surface layer of large roller bearings parts carried out on bearing steel 100CrMn6. Laboratory tests carried out on roller bearings elements eg. the axle railway wagons exploitation around 600 thousand km. Modern optical microscopy with fiber optic transmission and special software was used; scanning electron microscope was applied to analyze surface stereometry; profilometers made an analyze of seizure of co-working tribological parts: roller – race roller bearings. In addition, the documentation of characteristic tribological processes occurring during the exploitation the bearings was completed. Seizure zones contact surface which occur under high and variable loads and friction were found.

Fatigue and Fracture Mechanisms in Large Rolling Element Bearings

Fatigue in rolling bearings generally results in failure by pit -ting (spoiling). However, large bearings, most particularly those subjected to significant tensile hoop stress, sometimes fail due to more or less radial cracking, which may lead to fracture of the contacting raceways or of the rolling elements. Examples of this type of failure have been reported from a wide range of applications, suggesting that current understanding is imperfect. In the present paper, an analysis of crack initiation and propagation is presented and used to examine the conditions necessary to cause radial cracking and fracture in large bearing components, including rollers. The analysis includes the effects of hoop tensile stress and of fluid entrapment. Results of the analysis are used to demonstrate the significance of Hertz pressure, roller diameter and hoop stress, whether applied or residual. The results provide a reasonable explanation of the difference in the observed behavior between small and large roller bearings. A simple map is proposed in order to predict the failure mode to be expected in roller bearings operating at modest contact pressures. Presented at the 55th Annual Meeting Nashville, Tennessee May 7–11, 2000

Underbalance Drilling-Surface Control Systems

Abstract A closed system of surface control equipment for underbalance drilling is the safest method of controlling live wells. This new technology is particularly useful in both vertical and horizontal wells where invasion of drilling fluids into virgin formations can result in severe damage and low flow rate wells. The concept is to drill into these formations underbalanced so that there is no restriction to formation flow minimal damage and ultimately higher producing wells. This is achieved by utilizing a rotating BOP or double annular blowout preventers in combination with a choke manifold sample catcher, low stage/high stage separator, flarestack and a "live" flow through control system. The "closed system" is particularly useful in drilling in Jaw pressure and fractured reservoirs. It has been utilized to drill for oil and gas in carbonates and sandstone formations. Introduction During the past 18 months a significant number of oil and gas companies in Western Canada have switched from conventional drilling methods to underbalanced drilling technology when the target zone is reached. The normal operation is to drill to casing point with a conventional drilling method, set casing and cement. The heavier mud system is then changed out to a light fluid system and the well drilled ahead in an underbalanced controlled operation. The closed system on surface ensures that the well is being "controlled" during the entire drilling operation. To date over 100 wells in Western Canada have been safely drilled using this technique and it is the purpose of this paper to outline the technical results of drilling these formations underbalanced, The operational aspects are discussed in detail emphasizing the importance of the well control technique. The case studies will include a gas and an oil reservoir with example wells drilled overbalanced and underbalanced. The Closed System The closed system for underbalance drilling is shown in Figure 1. The principle components of the system are the wellhead connection. the rigid flowline piping, choke manifold, sample catcher, separator, flarestack and return flow line to the drilling fluid tank, rig pump and the mixing T where the nitrogen is mixed in with the liquid system and the continuation to the drilling head. Experience has shown that the surface equipment can be tied into the drilling contractors blowout preventer system using the following methods:Tie into the flowspoot on the blowout preventer (BOP) stack (Figure 1) orThe rotating blowout preventer (REOP) Figure 2.The Rotating Blow Out Preventor The rotating blowout preventer maintains surface back pressure up to 1,500 psi to allow drilling with air. gas. water or light muds. Drilling is faster, safer and less expensive in horizontal wells. The RBOP uses a hydraulically actuated kicking element supported on large roller bearings and isolated by mechanical seals Inside a large housing. The housing has a flange for mounting to the BOP stack and a return discharge flange. Hydraulic oil is used to actuate the package elements which ride against the belly or drill pipe.

Design and load rating analysis of the elastic support for a large roller bearing

Design and load rating analysis of the elastic support for a large roller bearing

Design and load rating analysis of the elastic support for a large roller bearing : ANDERSON, W. D., DELLINGER, C. L. Transactions of the American Society of Mechanical Engineers, Journal of Lubrication Technology, Vol 92, Series F, No 1 (Jan 1970) pp 113–120

Design and load rating analysis of the elastic support for a large roller bearing : ANDERSON, W. D., DELLINGER, C. L. Transactions of the American Society of Mechanical Engineers, Journal of Lubrication Technology, Vol 92, Series F, No 1 (Jan 1970) pp 113–120

Closure to “Discussions of ‘Design and Load Rating Analysis of the Elastic Support for a Large Roller Bearing’” (1970, ASME J. Lubr. Technol., 92, pp. 117–119)

Closure to “Discussions of ‘Design and Load Rating Analysis of the Elastic Support for a Large Roller Bearing’” (1970, ASME J. Lubr. Technol., 92, pp. 117–119)

Design and Load Rating Analysis of the Elastic Support for a Large Roller Bearing

The Basic Oxygen Furnace comprises a tiltable vessel supported by two trunnions in large roller bearings. To accommodate thermal expansion, the floating bearing is mounted on a deep curved beam which moves axially on two linear bearings. Under loads of 1 to 2 million pounds, the elastic deflection of this beam alters the static load capacity of the roller bearing. This paper describes a computer assisted analysis based on Castigliano’s First Theorem for determining the effective bearing capacity, and secondly for optimizing the beam design.

Progress in Rolling Bearing Vibration Research and Control

The effect of rolling bearing vibrations on machine noise is experimentally determined. The mechanics of bearing vibration generation and transmission are described. An analytical model for the bearing as a vibration generator is used to identify forcing frequencies, resonant frequencies, and amplitude relationships. Results of measurements of the radial, axial, and angular vibrations of both small ball and large roller bearings are cited. The effect on vibration of masses and compliances attached to the bearing is examined. A review of recent progress in the manufacture of smooth running ball and roller bearings is presented.

大形軸受の着脱法(<小特集>摩擦と潤滑)

大形軸受の着脱法(<小特集>摩擦と潤滑)