Acoustic emission based condition monitoring of hydraulic cylinder

In the recent years, there has been a growing concern for oil spill from the hydraulic cylinders in the offshore oil and gas industry. Failure of hydraulic cylinder seals is one of the foremost causes of oil spills. If the hydraulic seal is not replaced in time, it leads to oil leakage or particle contamination of the hydraulic fluid. Oil leakage from hydraulic cylinder also causes lack of force, variable speed and finally leads to an unstable hydraulic system. As the hydraulic seal is concealed within the hydraulic cylinder it is difficult to diagnose the seal quality from direct methods such as visual inspection. Premature failure of hydraulic seals leads to failure of the hydraulic cylinder and increases cost for maintenance and repair. In order to diagnose the deterioration of the seal quality in hydraulic cylinders it is necessary to have a maintenance strategy. Traditional time-based maintenance methods do not consider the current health of equipment, but follows a pre-defined schedule for inspection, which results in machine downtime if the equipment did not require any maintenance, or in worst case catastrophic failure due to breakdown. However, in recent decades, attempts have been made in industry to adopt condition monitoring (CM) methods as these methods give indirect information of the current health of the system. By adopting CM methods, maintenance of an equipment is only performed when it is effectively required. Therefore, in this work, acoustic emission (AE) based CM will be performed to determine AE features that can predict the seal failure of hydraulic cylinder at the very initial stages.