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TopBackground
This chapter distinguishes between maintenance policy and maintenance strategy; the latter is considered as an integrated series of decisions taken in four structural and six infrastructure decision elements (Pintelon & Pinjala, 2006). Some authors, however, use the same term for both concepts.
The choice of maintenance policies has been little analysed in the literature despite its importance for companies (Bertolini & Bevilacqua, 2006; Wang, Chu, & Wu, 2007). Until very recently this decision was taken based on the experience of the maintenance staff. However, this is a complex decision as it combines technical requirements for each machine with the business strategy. Thus, it is a decision which requires a great deal of thought, as different quantitative and qualitative criteria must be considered, which justifies the use of MCDA techniques.
Different types of maintenance policies can be defined:
Key Terms in this Chapter
Multiple Criteria Decision Analysis (MCDA) Techniques: A MCDA technique constitutes a rational and objective tool to improve understanding of underlying decision processes in the systemic processes and, to help the decision centre or group to compare the alternatives.
Maintenance Policy: Is a set of administrative, technical and managerial actions to apply during the life cycle of a machine, used to guide maintenance management decision making towards retaining certain operation conditions of a machine or dedicated to restoring the machine to said conditions.
Condition Based Maintenance: Is a maintenance policy in which physical parameters, such as vibrations, temperature, noise, etc., associated with an operating machine are detected, measured and recorded intermittently or continuously, for fault detection and prognosis (understood as the identification of future states of a machine depending on the load applied to the apparatus or process, and prediction of the remaining life of the machine).
Technique for Order Preference by Similarity to Ideal Solution (TOPSIS): This is an alternative method to ELimination and Choice Expressing REality (ELECTRE). It is based on the concept of selecting the alternative with a distance lower than the ideal solution, and with a distance superior to the most negative geometric solution. Classification of the alternatives is obtained by means of comparison of the relative distances.
Analytic Hierarchy Process (AHP): The mathematical foundations of AHP are described by Thomas Saaty in 1980. AHP is used to determine a ranking of the alternatives when all the decision criteria are considered simultaneously. AHP is based on three fundamental principles: pairwise comparison, decomposition, and synthesis. A hierarchy must be constructed to establish the relation between the goal, criteria, sub-criteria and alternatives.
Multiple Attribute Utility Theory (MAUT): The decision maker’s preferences are included by means of a utility function, U, defined for a set of criteria. This function can be obtained by means of an additive, multiplicative, or distributive mode from the marginal utility functions, U i (A). Therefore, if M alternatives A i are available, M marginal utility functions must be associated for each criterion U 1 (A), U 2 (A), ..., U M (A). The alternative selected must maximize the utility function.
Criterion: Is an aspect or issue relevant to the decision making problem. The set of criteria selected must be exhaustive, concise, non-redundant, and independent.