Keomany Bouvard

Condition-based dynamic maintenance operations planning & grouping. Application to commercial heavy vehicles

This paper aims at presenting a method to optimize the maintenance planning for a commercial heavy vehicle. Such a vehicle may be considered as a multi-components system. Grouping maintenance operations related to each component reduces the global maintenance cost of the system. Classically, the optimization problem is solved using a priori reliability characteristics of components. Two types of methods may be used, i.e. static or dynamic methods. Static methods provide a fixed maintenance planning, whereas dynamic methods redefine the groups of maintenance operations at each decision time. Dynamic procedures can incorporate component information such as component states or detected failures. For deteriorating systems, reliability characteristics of each component may be estimated thanks to deterioration models and may be updated when a degradation measure is available. This additional information on degradation features allows to better follow the real state of each component and to improve the maintenance planning.

Dynamic grouping maintenance with time limited opportunities

This paper presents firstly a dynamic grouping maintenance strategy for multi-component systems with positive economic dependence, which implies that combining maintenance activities is cheaper than performing maintenance on components separately. Preventive maintenance durations and multiple occurrences of maintenance activities within scheduling horizon are considered. Moreover, in a dynamic context, maintenance opportunities, defined as inactivity periods of the systems at which several maintenance activities could be executed with reduced maintenance costs, may randomly occur with time. The second objective of the paper is to propose a new algorithm to optimally update online the grouped maintenance planning by taking into account the maintenance opportunities. A numerical example of a five components system is finally introduced to illustrate the proposed dynamic grouping maintenance strategy.

A Maintenance Free Operating Period Policy for a Multi-component System with Different Information Levels on the Components State

This paper deals with the concept of Maintenance Free Operating Period (MFOP). This MFOP is defined as a period of operation during which the system should be able with a given level of confidence to carry out all its assigned missions without system faults or performance limitations. The idea is to ensure with a given level of confidence that no unscheduled repair operation will be required during each defined period of operation. The main objective of this article is to present an approach to optimize maintenance strategy and to evaluate the system design based on MFOP concept. In this paper, the system design includes the problems of available state information and reliability properties of components which strongly influence the maintenance policy accuracy. An example based on a sub-system of commercial heavy vehicle is introduced to illustrate the proposed methodology.