bearing failure Analysis Case Study

Problem

A paper plant was experiencing shaft and bearing failures on the non-drive end bearing on the breast roll of a paper machine. Several shaft design modifications were previously implemented by the plant, but were unsuccessful in eliminating the shaft and bearing failures. KHE was contracted to analyze the shaft and bearing application to determine the allowable wire loading for several shaft design options and to determine the sensitivity of the bearing to support misalignment.

Solution

KHE’s initial field evaluation helped to identify possible modifications of the bearing housing to allow for bearing alignment inspection during installation. Next, we generated a finite element model for each shaft design. Fatigue stress analysis was used to determine the wire loading limit for each design. An additional finite element model was used to determine the deflection of the bearing support due to the asymmetric loading inherent in the design.

Results

KHE’s analysis prevented the client from having to purchase an expensive forged journal. We determined that an existing design was adequate for the wire loading capability of the machine and that the bearing design was adequate with appropriate installation methods.