Ball Bearing System Research Articles

Damage identification using multivariate statistics: Kernel discriminant analysis

This paper is part of a series which illustrates how modern methods of multivariate statistics can be used to solve, or illuminate, damage identification problems. The technique discussed here is Kernel Discriminant Analysis (KDA), which can be used to assign damage classifications to measured data vectors. The data discussed is experimental data from a ball bearing system in an undamaged state and in four damage states. The classifiers are trained on the data after an initial pre-processing stage and also after a further statistical dimension reduction. The results from KDA are compared with a benchmark statistical method and with a neural network classifier.

A general discrete-time dynamic programming model for the opportunistic replacement policy and its application to ball-bearing systems

A general discrete-time, stochastic, dynamic-programming model of opportunistic corrective and preventive replacement policy is presented for multi-component systems with a different life distribution for each component. An approach to optimize the corrective and preventive maintenance policy is proposed, which is based on the introduction of the ‘oldest age’ concept and an ‘array dimensionality reduction technique’. The application of this policy to ball-bearing systems has resulted in considerable savings, as this paper demonstrates.

Fault detection in a ball bearing system using a moving window

A signal processing method to detect flaws in a ball bearing system is proposed. The method is formulated theoretically and the performance of the method is expressed in terms of signal to noise ratios. To verify the method, ball bearings with man-made defects and an actual production line were tested.

Cyclic Fatigue in Ceramics

Structural ceramics, such as silicon nitride, silicon carbide, alumina and zirconia, are promising instead of metallic materials, for practical applications to various kinds of engineering components, especially for high temperature applications. For example, automotive engine parts, such as turbocharger rotors and swirl chambers, and ball bearing systems have been produced on a commercial basis using these materials for the last ten years. These industrial motivations have promoted extensive progress in the research on evaluation of the strength properties of ceramics. In particular, cyclic fatigue has been investigated as one of the major concerns in the design of reliable ceramic components, and many researchers have been engaged in the field of cyclic fatigue in ceramics. As a result, new aspects such as crack bridging, R-curve behavior, fracture morphology and so forth have been clarified in the last decade. In this volume, the latest topics and experimental techniques in Japan, concerning ceramic fatigue under cyclic loading are provided. Twelve papers address questions concerning ceramic fatigue, and are classified according to subjects in three sections: `Fatigue Behaviour and Crack Growth`, `Fatigue Mechanisms` and `Statistical Properties and Application`. The former two sections are state-of-the-art references for a fundamental understanding of ceramic fatigue, while the third section presents more complicated analytical techniques for statistical treatment and engineering application

Study of electrical characteristics of the ball bearing motor

The electrical characteristics of the ball bearing electric motor are studied for applied steady currents ranging from 43.5 to 70.15 A. It is found that the ball bearing behaves like a motor when it starts self-rotating meaning that the shaft and inner race of the pair of the ball bearing system start rotating by themselves without the help of any external agent, but with a small efficiency at high currents. During self-rotation the motor's counterelectromotive force depends on the angular velocity of the shaft and inner race. The ball bearing's behavior at low currents is also explained when it is not self-rotating, (i.e. rotating with the help of a conventional motor). In the latter case, the motor does not behave like a generator. A theory, based on the electromagnetic interactions developed within each ball, is proposed to explain the action of the ball bearing as a motor. These interactions are caused by the ball's primary currents and magnetic fields and the effects of the induced magnetic field from the current of the motor's shaft. >

Observations on the systolic I-J stroke acceleration-force values of 49 male subjects from a roller ball-bearing ballistocardiographic bed

1. 1. The systolic I-J stroke acceleration-force values from a ball-bearing ballistic platform have been determined for 49 normal males. 2. 2. The wide range and overlap of expiratory and inspiratory acceleration-force values preclude the establishment of a too rigid range of quantitative values, and indicate the need for qualitative (Grade I–IV) evaluation of the ballistocardiogram. 3. 3. The force value obtained with the ball-bearing system is nearly equal to the result from the Starr high-frequency system, but is only 82 per cent of the force value from a differential pendulum.