In this work an improved bearing model is developed in order to investigate vibrations of ball bearing during run-up. A numerical bearing model was developed under assumptions that the inner race has only 2 DOF and that the outer race is deformable in the radial direction, and is modeled with finite elements. Centrifugal load effect and radial clearance are taken into account. The contact force between balls ans race is described by nonlinear Hertzian contact deformation. Various surface defects due to local deformations are introduced into the developed model. The detailed geometry of the local defects is modeled with Gauss function on the races and as a attended sphere for the rolling balls. The simulated vibrational response with the developed bearing model with faults was used to find suitable parameters for the envelope analysis and Hilbert-Huang transformation for identifying bearing faults at non stationary rotational frequency. With these parameters both methods were successful in identifying bearing faults from vibrations records obtained from experiments.
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COBISS.SI-ID: 262008064Editorial of Proceedings of an international scientific conference, ISVR - Institute of Sound and Vibration research -prganiser.
C.01 Editorial board of a foreign/international collection of papers/book
COBISS.SI-ID: 13005083This research presents numerical and experimental analysis of the structural dynamics at the vibration fatigue. The SMURF method has been enhanced and numerically verified for the case of base excitation. Furthermore, a novel accelerated fatigue testing methodology based on the structure's dynamic response has been presented in order to obtain material's Wöhler curve. A conservative fatigue life estimation due to the changes of structure's response has been experimentally confirmed for the case of base excitation with a random signal. Finally, a new methodology for the assessment of the fatigue parameters with base excitation with random signal has been presented and applied to the rivet joint.
D.09 Tutoring for postgraduate students
COBISS.SI-ID: 268799488The presented research characterizes the sensitivity-based normalisation of the mode shapes of small and light structures. The work focuses on resolving the problems with the measurement of the modal parameters of structures with small dimensions and mass (added mass to the structure, high resonant frequencies, ...). A survey of the existent methods for the measurement of the modal parameters within the experimental and operational modal analysis is performed. The methods that are suitable for small and light structures are examined in detail. Sensitivity-based mass normalisation of the operational mode shapes of small and light structures is analysed. The work presents three innovative methods that were developed for the measurement of the modal parameters of small and light structures. The correct functioning of these three methods is confirmed with the comparison of the numerical model and the experiment results. Special attention is given to the mass normalisation of mode shapes.
D.09 Tutoring for postgraduate students
COBISS.SI-ID: 13130267The first part of this research presents an experimental characterization of magnetostriction in electrical steel. The focus is on the dynamic suitability of the experimental set-up, enabling an undistorted measurement of the magnetostriction in a wide frequency range. Time and frequency domain analyses of the magnetostriction are performed with power approximations introduced for individual frequency components. The second part presents a numerical analysis of the magnetostriction-induced dynamics of laminated electrical-steel structures. A valid structural model and the introduced magnetostriction model together enable the assessment of the in-plane and the out-of-plane response.
D.09 Tutoring for postgraduate students
COBISS.SI-ID: 13125403