High Speed Testing of the Hollow Roller Bearing

1981 ◽  
Vol 103 (1) ◽  
pp. 1-5 ◽  
Author(s):  
W. L. Bowen ◽  
T. W. Murphy
Keyword(s):  
High Speed ◽  
Roller Bearing ◽  
Test Machine ◽  
Bending Fatigue ◽  
Speed Test ◽  
High Speeds ◽  
Full Complement ◽  
Safe Condition ◽  
Fail Safe ◽  
Cooling Ability

This bearing with its preloaded, hollow rollers has the qualities required for high speed operation. Roller hollowness improves cooling ability and its lighter weight reduces the centrifugal force against the raceway. Preloading between inner and outer races for 360 deg insures good roller guidance and minimizes roller skidding. However, the problems of operating a full complement of rollers at very high speeds were unknown. Also, limitations caused by roller bending fatigue needed investigation. To answer these questions, a high speed test machine was constructed and a hollow roller test bearing was designed for operation at 3 million DN. This paper describes the construction of a high speed test cell and subsequent testing of a full complement, preloaded, 115 mm hollow roller bearing. Testing culminated in a successful endurance test of 1000 hours at 26,100 RPM (3 million DN). The results verified several advantages regarding roller stability and antiskidding qualities as well as demonstrating a unique fail-safe condition.

Measurement of Wet cornering Traction of Tires

1971 ◽  
Vol 44 (4) ◽  
pp. 962-995 ◽  
Author(s):  
A. G. Veith
Keyword(s):  
Boundary Layer ◽  
High Speed ◽  
Elastohydrodynamic Lubrication ◽  
Speed Test ◽  
High Speeds ◽  
Wide Range ◽  
Low Speeds ◽  
Test Variability ◽  
Traction Testing ◽  
Tread Rubber

Abstract We have shown that the cornering wet traction performance of tires, as measured with a special cornering trailer, is influenced by a number of factors and their interaction with each other. Unlike conventional low speed “spin-out” wet cornering traction testing, we have evaluated tire traction over the range 30–60 mph. Over this range there is a marked speed dependence in the rating of various tread rubbers and tread patterns. In general, tread rubbers show a wide range of performance ratings at the lower speeds (30–35 mph) and a narrower range at high speeds (55–60 mph). Various tread patterns on the contrary show similar behavior at low speeds but a wide divergence in traction level at high speeds. Higher durometer tread compounds show improved high speed traction for any given rubber. Tread hardness cannot be used as an omnibus indicator of wet traction performance, however, as each rubber has its own separate correlation line. Low coefficient pavement can have either low or high degrees of macrotexture, but the lack of microtexture or harshness (asperities in the fraction of a millimeter range) produces this type of pavement. Tires must perform safely on such pavement sections of public highways and the testing reported here was done on such test surfaces. Evaluations of four types of tread rubber show that they rank from high to low traction level in the order: SBR, Butyl, NR and BR (solution type) on smooth, low microtexture surfaces. Although BR gives low traction when used alone it is not so used in commercial tread compounds. When properly blended with SBR or NR, tread compounds containing BR give satisfactory traction performance and improved wear performance. The overall behavior of tires can be explained in terms of the concepts of hydrodynamic and boundary layer lubrication. At low speeds boundary layer lubrication predominates on all but the smoothest pavements. This accounts for the marked influence of tread rubber at low speeds. At high speeds both thick and thin film elastohydrodynamic lubrication predominate. In this speed range tread materials play a lesser role and tread pattern or geometry plays a larger role. The relative softness and deformability of tread compound, compared to pavement aggregate, accounts for the importance of elastohydrodynamic lubrication. Drawing on the work of many previous investigators and the data of this work it is postulated that the fraction of the tire contact area of a cornering tire that is in the elastohydrodynamic mode of lubrication is a linear function of speed. This accounts for the good linearity of the plots of traction as a function of speed. Test variability is discussed and steps taken to measure and control such relevant factors as water depth are outlined. The use of statistically designed testing programs with their inherent averaging character are advocated for those doing this work. In addition to their power at averaging test results, such designs uncover the strong interaction between tire and test variables that underlie all wet traction testing.

The CFD Modeling of the Water Braking Phenomena for the Holloman High-Speed Test Track

2019 ◽  
Author(s):  
Jose Terrazas ◽  
V. M. Krushnarao Kotteda ◽  
Vinod Kumar ◽  
Robert Edmonds ◽  
Michelle Zeisset
Keyword(s):  
High Speed ◽  
Force Balance ◽  
Cfd Modeling ◽  
Critical Infrastructures ◽  
Momentum Exchange ◽  
Test Track ◽  
Speed Test ◽  
High Speeds ◽  
Time Test ◽  
Very High

Abstract At the Holloman High-Speed Test Track (HHSTT), momentum exchange with water is used to decelerate sleds from very high speeds (> Mach 1). This process, at the HHSTT, is called ‘water braking’. Improving the prediction capabilities of water braking phenomena has the potential to result in radical changes in the designs of sleds, improve rocket sled velocity-time test profile predictions, provide greater confidence of braking mechanisms, and decrease risk in the recovery of critical infrastructures. Understanding the water?s behavior with the sled is critical to predicting how the water could damage the sled, which affects the recoverability of the sled and can determine the success of a mission. Traditionally, sled design for the test missions for water braking has been guided by empirical/hand calculations to estimate the forces on various components. The calculations involved various approximations in arriving at the force balance law and predicting the acceleration/deceleration profile. In partnership with the HHSTT, we performed preliminary simulations to develop a predictive model for the HHSTT sled tests at various velocity regimes. The (preliminary) CFD results from different geometry configurations for the sled and modeling parameters will be presented.

Rotating Bending Fatigue Tests on Aluminum Alloy AISI-SAE 6061-T6 at High Speed (150 Hz), and Close to Elastic Limit

2009 ◽  
Vol 65 ◽  
pp. 79-88
Author(s):  
Gonzalo Domínguez Almaraz ◽  
Edgar Tapia Silva ◽  
Mauricio Guzmán Tapia ◽  
Jesús Villalón López
Keyword(s):  
Aluminum Alloy ◽  
High Speed ◽  
Elastic Limit ◽  
High Stress ◽  
Fatigue Tests ◽  
Test Machine ◽  
General Description ◽  
Bending Fatigue ◽  
Rotating Bending Fatigue ◽  
Rotating Bending

This work deals with rotating bending fatigue tests at high speed (150 Hz), carried out on aluminum alloy AISI-SAE 6061-T6 for which the highest experimental stress inside the specimen is close to the elastic limit of material. Simulation results are obtained by Visual Nastran software in order to determine the numerical stress and strain distributions inside the specimen; then, this information is used for the experimental set up. A general description of experimental test machine and experimental conditions are developed in first sections, following section present the experimental results and discussion about the observed failure origin related to discontinuities and the associated high stress zones. A principal contribution of this work is related to the analysis of fracture surfaces and its correlation with experimental fatigue endurance: a simple model is proposed for the prediction of fatigue life of this aluminum alloy under high speed rotating bending fatigue tests, based on the surface density of associated fatigue macro-plastic deformation zones close the crack initiation.

A Statistical Study of Process Variables to Optimize a High Speed Curtain Coater: Part I

TAPPI Journal ◽  
2009 ◽  
Vol 8 (1) ◽  
pp. 20-26 ◽  
Author(s):  
PEEYUSH TRIPATHI ◽  
MARGARET JOYCE ◽  
PAUL D. FLEMING ◽  
MASAHIRO SUGIHARA
Keyword(s):  
Boundary Layer ◽  
Experimental Design ◽  
High Speed ◽  
Statistical Study ◽  
Process Variables ◽  
High Speeds ◽  
The Stability ◽  
Air Removal ◽  
Removal System

Using an experimental design approach, researchers altered process parameters and material prop-erties to stabilize the curtain of a pilot curtain coater at high speeds. Part I of this paper identifies the four significant variables that influence curtain stability. The boundary layer air removal system was critical to the stability of the curtain and base sheet roughness was found to be very important. A shear thinning coating rheology and higher curtain heights improved the curtain stability at high speeds. The sizing of the base sheet affected coverage and cur-tain stability because of its effect on base sheet wettability. The role of surfactant was inconclusive. Part II of this paper will report on further optimization of curtain stability with these four variables using a D-optimal partial-facto-rial design.

A FAST ROTATING BENDING FATIGUE TEST MACHINE

2017 ◽  
Author(s):  
Marco Antonio Meggiolaro ◽  
Jaime T P Castro ◽  
Rodrigo de Moura Nogueira
Keyword(s):  
Fatigue Test ◽  
Test Machine ◽  
Bending Fatigue ◽  
Bending Fatigue Test ◽  
Rotating Bending Fatigue ◽  
Rotating Bending ◽  
Fast Rotating

RED CUT COBALT

Alloy Digest ◽  
1980 ◽  
Vol 29 (8) ◽  
Keyword(s):  
Fracture Toughness ◽  
Cast Iron ◽  
High Speed ◽  
Elevated Temperatures ◽  
High Speed Steel ◽  
Heat Treating ◽  
High Speeds ◽  
Red Hardness ◽  
Nonferrous Alloys ◽  
Cutting Point

Abstract RED CUT COBALT steel is made by adding 5% cobalt to the conventional 18% tungsten -4% chromium-1% vanadium high-speed steel. Cobalt increases hot or red hardness and thus enables the tool to maintain a higher hardness at elevated temperatures. This steel is best adapted for hogging cuts or where the temperature of the cutting point of the tool in increased greatly. It is well adapted for tools to be used for reaming cast-iron engine cylinders, turning alloy steel or cast iron and cutting nonferrous alloys at high speeds. This datasheet provides information on composition, physical properties, and hardness as well as fracture toughness. It also includes information on forming, heat treating, and machining. Filing Code: TS-367. Producer or source: Teledyne Vasco.

CPM REX 25

Alloy Digest ◽  
1980 ◽  
Vol 29 (7) ◽  
Keyword(s):  
Heat Treatment ◽  
High Speed ◽  
High Speed Steel ◽  
High Hardness ◽  
Heat Treating ◽  
High Speeds ◽  
Aisi Type ◽  
Tool Performance ◽  
End Mills ◽  
Machining Operations

Abstract CPM REX 25 is a super high-speed steel made without cobalt. It is comparable to AISI Type T15 cobalt-containing high-speed steel in response to heat treatment, properties, and tool performance. CPM REX 25 is recommended for machining operations requiring heavy cuts, high speeds and feeds, and difficult-to-machine materials of high hardness and abrasion resistance. Typical applications are boring tools, drills, gear cutters, punches, form tools, end mills and broaches. This datasheet provides information on composition, physical properties, hardness, and elasticity as well as fracture toughness. It also includes information on forming, heat treating, machining, and surface treatment. Filing Code: TS-365. Producer or source: Crucible Materials Corporation.

Analysis of Crack Propagation in Roller Bearings Using the Boundary Integral Equation Method—A Mixed-Mode Loading Problem

1988 ◽  
Vol 110 (3) ◽  
pp. 408-413 ◽  
Author(s):  
L. J. Ghosn
Keyword(s):  
Integral Equation ◽  
Stress Intensity ◽  
Crack Propagation ◽  
Boundary Integral Equation ◽  
Stress Intensity Factors ◽  
High Speed ◽  
Roller Bearing ◽  
Boundary Integral ◽  
Boundary Integral Method ◽  
Intensity Factors

Crack propagation in a rotating inner raceway of a high-speed roller bearing is analyzed using the boundary integral method. The model consists of an edge plate under plane strain condition upon which varying Hertzian stress fields are superimposed. A multidomain boundary integral equation using quadratic elements was written to determine the stress intensity factors KI and KII at the crack tip for various roller positions. The multidomain formulation allows the two faces of the crack to be modeled in two different subregions making it possible to analyze crack closure when the roller is positioned on or close to the crack line. KI and KII stress intensity factors along any direction were computed. These calculations permit determination of crack growth direction along which the average KI times the alternating KI is maximum.

A Method of Making High-Speed Compression Tests on Small Copper Cylinders

1948 ◽  
Vol 15 (3) ◽  
pp. 248-255
Author(s):  
E. T. Habib
Keyword(s):  
High Speed ◽  
Underwater Explosion ◽  
Dynamic Calibration ◽  
Test Apparatus ◽  
Compression Tests ◽  
High Speeds

Abstract In mechanical gages used to measure the pressure from an underwater explosion, small copper cylinders are compressed at high speeds. This paper describes the test apparatus designed for the dynamic calibration of these cylinders, presents the results obtained with this apparatus, and compares these results with those obtained by other experimenters.

Skidding research of a high-speed cylindrical roller bearing with beveled cage pockets

2020 ◽  
Vol 72 (7) ◽  
pp. 969-976
Author(s):  
Yanbin Liu ◽  
Zhanli Zhang
Keyword(s):  
Peer Review ◽  
Tilt Angle ◽  
High Speed ◽  
Hydrodynamic Lubrication ◽  
Roller Bearing ◽  
Front Wall ◽  
Dynamics Model ◽  
Content Type ◽  
Cylindrical Roller Bearing ◽  
Cylindrical Roller

Purpose This study aims to uncover the influencing mechanism of the tilt angles of the cage pocket walls of the high-speed cylindrical roller bearing on the bearing skidding. Design/methodology/approach A novel cylindrical roller bearing with the beveled cage pockets was proposed. Using the Hertz contact theory and the elastohydrodynamic and hydrodynamic lubrication formulas, the contact models of the bearing were built. Using the multibody kinematics and the Newton–Euler dynamics theory, a dynamics model of the bearing was established. Using the Runge–Kutta integration method, the dynamics simulations and analysis of the bearing were performed. Findings The simulation results show that the effects of the tilt angles of the front and rear walls of the pocket on the bearing skidding are remarkable. Under a 5° tilt angle of the front wall of the pocket and a 10° tilt angle of the rear wall, the bearing skidding can be effectively decreased in the rotational speed range of 10,000-70,000 r/min. Originality/value In this paper, a novel cylindrical roller bearing with the beveled cage pockets was proposed; a dynamics model of the bearing was established; the influence mechanism of the tilt angles of the front and rear walls of the pocket on the bearing skidding was investigated, which can provide fundamental theory basis for optimizing the pocket. Peer review The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-01-2020-0035/

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