L. Kania

Bio: L. Kania is an academic researcher from Częstochowa University of Technology. The author has contributed to research in topics: Slewing bearing & Bearing (mechanical). The author has an hindex of 6, co-authored 23 publications receiving 217 citations.

Computation of the general carrying capacity of slewing bearings

Abstract: Purpose – The purpose of this paper is to discuss the calculation problem of the real carrying capacity of slewing bearings. The selection of slewing bearing to heavy-duty machine according to catalogue carrying capacity and also according to locally determined real carrying capacity is insufficient and it can be the cause of the damage of machine during exploitation. Design/methodology/approach – The concepts of the local, total and general capacities is defined. The general capacity is a logical product of the local capacities. It is particularly useful in an analysis of slewing bearings incorporated into machines with complex structures. The FEM is applied in computations. The formation method of the mathematical model of a bearing is presented. Findings – The computations of the local capacities and general capacity of a bearing for the limiting load of the bearing traces and the limiting tension of the bolts fastening the bearing were carried out. Considerations were illustrated by an example of the ...

Modelling the Contact between the Rolling Elements and the Raceways of Bulky Slewing Bearings

Abstract: In slewing bearings, a great number of contact pairs are present on the contact surfaces between the rolling elements and raceways of the bearing. Computations to determine the load of the individual rolling elements, taking into account the flexibility of the bearing ring, are most often carried out using the finite element method. Construction of a FEM full model of the bearing, taking into account the shape of the rolling elements and the determination of the contact problem for every rolling element, leads to a singularity of stiffness matrix, which in turn makes the problem impossible to solve. In FEM models the rolling elements are replaced by one-dimensional finite elements (linear elements) to simplify the computation procedure and to obtain an optimal time for computations. The methods of modelling the rolling elements in the slewing bearing, in which balls have been replaced by truss elements with a material non-linear characteristic located between the raceway centres of the curvatures in their axial section, are presented in the paper.

Condition monitoring of naturally damaged slow speed slewing bearing based on ensemble empirical mode decomposition

Abstract: There have been extensive studies on vibration based condition monitoring, prognosis of rotating element bearings; and reviews of the methods on how to identify bearing fault and predict the final failure reported widely in literature. The investigated bearings commonly discussed in the literatures were run in moderate and high rotating speed, and damages were artificially introduced e.g. with artificial crack or seeded defect. This paper deals with very low rotational-speed slewing bearing (1–4.5 rpm) without artificial fault. Two real vibration data were utilized, namely data collected from lab slewing bearing subject to accelerated life test and from a sheet metal company. Empirical mode decomposition (EMD) and ensemble empirical mode decomposition (EEMD) were applied in both lab slewing bearing data and real case data. Outer race fault (BPFO) and rolling element fault (BSF) frequencies of slewing bearing can be identified. However, these fault frequencies could not be identified using fast Fourier transform (FFT).