عنوان مقاله [English]
During the operation of rotating machines in large industries such as power plants, the journal bearing failures are numerous. In order to avoid catastrophic damages in bearings and reducing the causes, evaluation of the root causes of bearing failures is important. In this paper, we investigate the root causes of failure in journal bearings, using one of the powerful methods of maintenance fields, which has been named failure mode and effect analysis. In order to collect bearing failures data, have been referred to the six power plants and failures information is obtained. Using this data and charts related to the occurrence probability, detection probability and severity rates which are the main parameters of this method for determining the risk priority number, the failure mode and effect analysis method has been implemented. According to this method, the main failure has been identified as wear. Then, using the well-known model of bearing wear geometries and computational fluid dynamics analysis for solving Navier-Stocks equations, effects of wear on the bearing load capacity, maximum lubrication pressure, in the different locations of wear, in the lower half of the bearing, has been investigated. Finally, the results of the finite element analysis have been compared to the results of the theory and solving the Sommerfeld-Harrison equation for bearing without wear. Also, to reduce the effects of this failure, another bearing geometry has been proposed in a similar situation with a load capacity greater than the custom one.