This work aims to develop the theoretical fundamentals and numerical details of new software, dedicated to the simulation of the dynamic behavior of rotating ball bearings in the presence of localized surface defects. In this article, the generation of vibration by a point defect in a rolling element bearing is modeled as a function of the rotation of the bearing, of the distribution of the load in the bearing, of the bearing structure elasticity, of the oil film characteristics, and of the transfer path between the bearing and the transducer. The numerical model is developed with the assumption that the dynamic behavior of the bearing can be represented by a coupled three-degree-of-freedom system, after which the governing equations of the simulation model are solved using computer simulation techniques. A new application, called BEAT (BEAring Toolbox), was developed in order to simulate bearings' vibratory response to the excitations produced by localized defects. By adding a noisy response due to the sliding friction occurring between the moving parts to the impulsive response caused by localized defects, the BEAT software is able to provide realistic results, similar to those produced by a sensor during experimental measurements.

The development of a powerful new magnetorheological fluid (MRF), together with recent progress in the understanding of the behavior of such fluids, has convinced researchers and engineers that MRF dampers are among the most promising devices for semi-active automotive suspension vibration control, because of their large force capacity and their inherent ability to provide a simple, fast and robust interface between electronic controls and mechanical components.In this paper, theoretical and experimental studies are performed for the design, development and testing of a completely new MRF damper model that can be used for the semi-active control of automotive suspensions. The MR damper technology presented in this paper is based on a completely new approach where, in contrast to in the conventional solutions where the coil axis is usually superposed on the damper axis and where the inner cylindrical housing is part of the magnetic circuit, the coils are wound in a direction perpendicular to the damper axis. The paper investigates approaches to optimizing the dynamic response and provides experimental verification.Both experimental and theoretical results have shown that, if this particular model is filled with an 'MRF 336AG' MR fluid, it can provide large controllable damping forces that require only a small amount of energy. For a magnetizing system with four coils, the damping coefficient could be increased by up to three times for an excitation current of only 2 A. Such current could be reduced to less than 1 A if the magnetizing system used eight small cores. In this case, the magnetic field will be more powerful and more regularly distributed. In the presence of harmonic excitation, such a design will allow the optimum compromise between comfort and stability to be reached over different intervals of the excitation frequencies.

The paper presents a fast, accurate and simple systematic approach for online condition monitoring and severity identification of ball bearings. This approach utilizes compact 1D convolutional neural networks (CNNs) to identify, quantify, and localize bearing damage. The proposed approach is verified experimentally under several single and multiple damage scenarios. The experimental results demonstrated that the proposed approach can achieve a high level of accuracy for damage detection, localization and quantification. Besides its realtime processing ability and superior robustness against the highlevel noise presence, the compact and minimally-trained 1D CNNs in the core of the proposed approach can handle new damage scenarios with utmost accuracy.

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This article presents a new concept design for magnetorheological dampers, where the excitation circuit and magnetic field are applied from outside the magnetorheological chamber. This magnetorheological damper was designed and built to decrease the intrusive manufacturing operations and to maximize the working efficiency. The experimental tests made on the first prototype featuring this new technology was promising. The excitation of a set of 12 coils surrounding the body of the damper, by an electric current of 5 A, managed to increase the damping coefficient by up to 75%. A similar performance could be obtained by a current 9.4 times lower if the magnetic circuit is designed correctly. Compared to other devices, the actual design tolerates more the temperature elevation caused by the feeding of coils with high-intensity current, just because the heat is radiated outwards instead of being transferred directly to the magnetorheological fluid like in conventional designs. Finally, the numerical simulations made on Matlab show that the new magnetorheological damper, when mounted on a commercial vehicle, can considerably enhance its dynamic behavior and bring it back quickly to its stable position when the tires hit a bump on the road.