RELIABILITY OF MACHINERY USING FATIGUE DAMAGE ACCUMULATION DUE TO RANDOM VIBRATIONS

A new approach to machinery maintenance using fatigue damage accumulation theory is presented. The vibration generated by industrial equipment is related to the stress history experienced by the internal machine elements at the corresponding measurement points assuming a linear elastic and isotropic behavior. The resultant stress history is modelled as a piecewise stationary, Gaussian wide-band process. Employing Miner's linear damage hypothesis in conjunction with available constant-amplitude fatigue data, expression for the expected accumulated fatigue damage and its variance are developed. A machinery maintenance programme based on the accumulated damage parameters calculated directly from the properties of the exhibited vibration history is proposed. The main advantage of this method is that it provides equipment reliability in terms of known and measureable system properties.