Towards a physics based prognostic model for bearing - Spall initiation and propagation

Machinery prognosis is the forecast of the remaining operational life, future condition, or probability of reliable operation of equipment based on the acquired condition monitoring data. The full process of prediction that is based on the condition of the equipment and the failure physics may be separated into two steps. The first step is diagnostics. It includes characterization of the defect in terms of location (in what component and where in the component), type, and extent. The second step is prognostics. It includes using the characterization of the defect with the estimated load in order to estimate the propagation of the defect as a function of time. Models for defect propagation can be statistical models or physical models (mathematical description of the physics of the failure growth), such as crack propagation. Physical models attempt to combine system-specific mechanical knowledge, defect growth formulas, and vibration data to provide knowledge-rich prognosis output. The goal of this research is to enable the estimation of the remaining useful life of rolling element bearings.