Prediction of Ball Fatigue Life in a Ball/V-Ring Test Rig

1997 ◽  
Vol 119 (3) ◽  
pp. 365-370 ◽  
Author(s):  
T. A. Harris
Keyword(s):  
Fatigue Life ◽  
Fatigue Failure ◽  
Life Prediction ◽  
Prediction Method ◽  
Ring Test ◽  
Ball Bearings ◽  
Test Rig ◽  
Material Life ◽  
Endurance Testing ◽  
Fatigue Endurance

Standard load and life ratings of ball bearings are based on fatigue failure of the bearing inner and outer raceway surfaces. The rating equations are derived from the mathematical and experimental work of Gustav Lundberg and Arvid Palmgren conducted in Sweden during the 1930s and 1940s; they considered the occurrence of subsurface-initiated, ball fatigue failure highly improbable. In modern ball bearings, this phenomenon occurs occasionally, creating the need for a life prediction means. Ball/v-ring rig fatigue endurance testing is a currently used method to screen ball materials and processing methods, particularly for aircraft applications. As a first step toward predicting ball fatigue life in bearings, the Lundberg-Palmgren and Ioannides-Harris life prediction methods were applied to ball/v-ring test data. The latter method predicted ball fatigue lives which correlated well with the measured ball lives. The Lundberg-Palmgren life prediction method modified using currently accepted material-life and lubrication-life factors did not yield satisfactory correlation.

Fatigue Failure Progression in Ball Bearings

2000 ◽  
Vol 123 (2) ◽  
pp. 238-242 ◽  
Author(s):  
Michael N. Kotzalas ◽  
Tedric A. Harris
Keyword(s):  
Mathematical Model ◽  
Fatigue Life ◽  
Fatigue Failure ◽  
Heat Generation ◽  
Ring Test ◽  
Ball Bearings ◽  
Test Rig ◽  
Component Failure ◽  
Rolling Contacts ◽  
Total Failure

Typically, the life of a component containing rolling contacts is defined as the time to the initiation of a fatigue spall. Initiation of a spall does not always cause the component to stop performing its designed function. Operating the component past the initiation of a spall increases the heat generation rates and vibrations, eventually leading to total failure. A ball/v-ring test rig was used to initiate and progress spalls on bearing balls where spall progression was measured as a function of time, and vibrations monitored using accelerometers. A spall progression life mathematical model for balls endurance tested in the v-ring rig was created by extending the Ioannides–Harris fatigue life theory. Also, excessive vibratory loading was determined to be the major cause of total component failure.

On the Accuracy of Rolling Bearing Fatigue Life Prediction

1996 ◽  
Vol 118 (2) ◽  
pp. 297-309 ◽  
Author(s):  
T. A. Harris ◽  
J. I. McCool
Keyword(s):  
Fatigue Life ◽  
Life Prediction ◽  
Prediction Method ◽  
Rolling Bearing ◽  
Turbine Engines ◽  
Gas Turbine Engines ◽  
Critical Design ◽  
Bearing Life ◽  
Limit Stress ◽  
Fatigue Endurance

Ball and roller bearings are designed to meet endurance requirements basically determined according to the Standard fatigue life calculation method. This method is based on the Lundberg-Palmgren fatigue life theory as modified by reliability, material, and lubrication factors. As application load and spied requirements have increased, the Lundberg-Palmgren method has resulted in bearings of increased size, adding unnecessarily to the size and weight of mechanisms. This is a critical design situation for weight and size-sensitive components such as aircraft gas turbine engines and helicopter power transmissions. The bearing life prediction method developed by Ioannides and Harris recognizes the existence of a fatigue limit stress. If the stresses an operating bearing experiences do not exceed the limit stress, the bearing can achieve infinite life. In any case, the method tends to predict longer lives than the Lundberg-Palmgren method. This paper evaluates the life prediction accuracies of the Lundberg-Palmgren and Ioannides-Harris methods by comparing lives calculated according to these methods and to those actually experienced in 62 different applications. As a result of the investigation, the Ioannides-Harris method is shown to more accurately predict bearing fatigue endurance.

Micromechanics Method to Evaluate Fatigue Life of Ni-Based Superalloys during Morphological Evolution

2008 ◽  
Vol 385-387 ◽  
pp. 221-224
Author(s):  
Wen Ping Wu ◽  
Ya Fang Guo ◽  
Yue Sheng Wang
Keyword(s):  
Fatigue Life ◽  
Plastic Strain ◽  
Life Prediction ◽  
Morphological Evolution ◽  
Mean Field ◽  
Prediction Method ◽  
Field Method ◽  
External Stress ◽  
Equivalent Inclusion ◽  
Evolution Of Precipitates

A quantitative life prediction method has been proposed to evaluate fatigue life during morphological evolution of precipitates in Ni-based superalloys. The method is essentially based on Eshelby’s equivalent inclusion theory and Mori-Tanaka’s mean field method. The shape stability and life prediction are discussed when the external stress and matrix plastic strain are applied. The calculated results show that the fatigue life is closely related with microstructures evolution of precipitates. The magnitude and sign of the external stress and matrix plastic strain have an important effect on fatigue life of Ni-based superalloys during the morphological evolution of precipitates.

Life Prediction Method of CC and DS Ni Base Superalloys Under High Temperature Biaxial Fatigue Loading

2010 ◽  
Vol 132 (11) ◽  
Author(s):  
Takashi Ogata
Keyword(s):  
Fatigue Life ◽  
Gas Turbine ◽  
Turbine Blade ◽  
Life Prediction ◽  
Compressive Strain ◽  
Prediction Method ◽  
Strain Range ◽  
Fatigue Loading ◽  
Normal Strain ◽  
Biaxial Fatigue

Polycrystalline conventional casting (CC) and directionally solidified (DS) Ni base superalloys are widely used as gas turbine blade materials. It was reported that the surface of a gas turbine blade is subjected to a biaxial tensile-compressive fatigue loading during a start-stop operation, based on finite element stress analysis results. It is necessary to establish the life prediction method of these superalloys under biaxial fatigue loading for reliable operations. In this study, the in-plane biaxial fatigue tests with different phases of x and y directional strain cycles were conducted on both CC and DS Ni base superalloys (IN738LC and GTD111DS) at high temperatures. The strain ratio ϕ was defined as the ratio between the x and y directional strains at 1/4 cycle and was varied from 1 to −1. In ϕ=1 and −1. The main cracks propagated in both the x and y directions in the CC superalloy. On the other hand, the main cracks of the DS superalloy propagated only in the x direction, indicating that the failure resistance in the solidified direction is weaker than that in the direction normal to the solidified direction. Although the biaxial fatigue life of the CC superalloy was correlated with the conventional Mises equivalent strain range, that of the DS superalloy depended on ϕ. The new biaxial fatigue life criterion, equivalent normal strain range for the DS superalloy was derived from the iso-fatigue life curve on a principal strain plane defined in this study. Fatigue life of the DS superalloy was correlated with the equivalent normal strain range. Fatigue life of the DS superalloy under equibiaxial fatigue loading was significantly reduced by introducing compressive strain hold dwell. Life prediction under equibiaxial fatigue loading with the compressive strain hold was successfully made by the nonlinear damage accumulation model. This suggests that the proposed method can be applied to life prediction of the gas turbine DS blades, which are subjected to biaxial fatigue loading during operation.

Fatigue Life Prediction of Buckling String with Cracks in Horizontal Wells of Mining Engineering

2012 ◽  
Vol 577 ◽  
pp. 127-131 ◽  
Author(s):  
Peng Wang ◽  
Tie Yan ◽  
Xue Liang Bi ◽  
Shi Hui Sun
Keyword(s):  
Fatigue Life ◽  
Prediction Model ◽  
Life Prediction ◽  
Horizontal Well ◽  
Drill Pipe ◽  
Prediction Method ◽  
Drill String ◽  
Fatigue Life Prediction ◽  
Mining Engineering ◽  
Life Prediction Model

Fatigue damage in the rotating drill pipe in the horizontal well of mining engineering is usually resulted from cyclic bending stresses caused by the rotation of the pipe especially when it is passing through curved sections or horizontal sections. This paper studies fatigue life prediction method of rotating drill pipe which is considering initial crack in horizontal well of mining engineering. Forman fatigue life prediction model which considering stress ratio is used to predict drill string fatigue life and the corresponding software has been written. The program can be used to calculate the stress of down hole assembly, can predict stress and alternating load in the process of rotating-on bottom. Therefore, establishing buckling string fatigue life prediction model with cracks can be a good reference to both operation and monitor of the drill pipe for mining engineering.

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