Experimental Study for Vibration Behaviors of Locally Defective Deep Groove Ball Bearings under Dynamic Radial Load

Rolling element bearings are used in many mechanical systems at the revolute joints for sustaining the dynamic loads. Thus, the reliable and efficient functioning of such systems critically depends on the good health of the employed rolling bearings. Hence, health monitoring of rolling bearings through their vibration responses is a vital issue. In this paper, an experimental investigation has been reported related to the vibration behaviours of healthy and locally defective deep groove ball bearings operating under dynamic radial load. The dynamic load on the test bearings has been applied using an electromechanical shaker. The vibration spectra of the healthy and defective deep groove ball bearings in time and frequency domains have been compared and discussed. Overall vibration increases in presence of local defects and dynamic radial load. 1. Introduction Rolling element bearings are used in many mechanisms and machines to achieve the operational objectives. For reliable and efficient functioning of rolling bearings employed in such mechanical systems, their health monitoring in terms of vibration responses is an essential task. Though the rolling bearings are manufactured with maximum care using high precision machine tools, the bearings may develop early defects during their usage depending upon the nature of operating parameters and working environments. It is also worth noticing here that the rolling bearings of several mechanisms and machines are often subjected to dynamic loads. Thus, a need arises to explore the role of bearing defects on its vibration behaviours in presence of dynamic radial load. Rolling bearings are mainly subjected to vibrations because of inherent nonlinearity, which arises due to Hertzian load deformation relationship, varying compliance, clearance, local and distributed defects, and so forth. Though the vibration studies of bearings in presence of distributed defects have been reported in depth by many researchers [1–5], in this paper, mainly, articles dealing with the vibrations of locally defective rolling bearings have been reviewed and reported. Among some prior studies, McFadden and Smith [6, 7] have presented a simple model to describe the vibrations of rolling element bearings in presence of single and multiple point local defects on the inner races. A comparison of predicted and measured vibration spectra is also provided by the authors with relevant discussions. Later on, Su and Lin [8] have extended the model reported in [6] for describing the bearings’ vibrations under various types of loadings. The