A study of maintenance policy for system with competing failure modes, wear failure and delta-shock failure

International audienceIn our study, the deteriorating system fails either because the deterioration exceeds a predetermined failure threshold L or because the interval between two successive shocks is less than a threshold , which corresponds to two failure modes: irreparable and repairable. The system deterioration is modeled by a Gamma process and the shocks occur following a Poisson process. The duration of the shock is negligible so it does not affect the system deterioration. As the system deteriorates, the threshold also increases, which means that when the system deteriorating seriously it is more vulnerable to the failure. After the minimal repair, the failure rate of the system remains constant. The deterioration state of the system can only be observed at inspection. The shock can be detected once it has occurred. In order to avoid the failure cause by the shock, it is reasonable to schedule the maintenance after a shock, such as the scheduled halt of the system to avoid the delta−shock failure and minimal repair. The effect of the cost of the scheduled halt will be studied