Condition Based Maintenance Optimization for Faulty Gearbox under Continuous Noise Monitoring

This paper considers a condition-based maintenance optimization for continuously degrading systems under continuous noise response in terms of sound pressure level monitoring. After maintenance, the states of the system are randomly distributed with residual damage. An optimization technique is used to solve a preventive maintenance problem for cracked gear tooth system. In this work, the situations where cracked gear tooth system has several ranges of performance levels are considered. To enhance cracked gear tooth system availability or (reliability), possible schedule preventive maintenance actions are performed and affect strongly the effective age. Moreover, the technique is used to generate an optimal sequence of maintenance actions providing system working with the desired level of availability or (reliability) during its lifetime with minimal maintenance cost rate. A single stage gearbox is used for this study, where multi-time tests were carried on healthy and faulty gearboxes individually. The measured sound pressure levels were collected where hazard lifetime (LT) was determined at failure based on the Weibull distribution with assured reliability. The results indicate that the saving expected costs of either health or faulty gearbox, the basic cost, availability; and maintenance cost and availability savings have been estimated. On the other hand, the operating time between failure and optimum points for basic cost, availability and maintenance cost and availability savings are all considered.