Optimal maintenance is the discipline within
operations research
Operations research ( en-GB, operational research) (U.S. Air Force Specialty Code: Operations Analysis), often shortened to the initialism OR, is a discipline that deals with the development and application of analytical methods to improve decis ...
concerned with maintaining a system in a manner that maximizes
profit
Profit may refer to:
Business and law
* Profit (accounting), the difference between the purchase price and the costs of bringing to market
* Profit (economics), normal profit and economic profit
* Profit (real property), a nonpossessory inter ...
or minimizes
cost
In production, research, retail, and accounting, a cost is the value of money that has been used up to produce something or deliver a service, and hence is not available for use anymore. In business, the cost may be one of acquisition, in whic ...
. Cost functions depending on the
reliability
Reliability, reliable, or unreliable may refer to:
Science, technology, and mathematics Computing
* Data reliability (disambiguation), a property of some disk arrays in computer storage
* High availability
* Reliability (computer networking), a ...
,
availability
In reliability engineering, the term availability has the following meanings:
* The degree to which a system, subsystem or equipment is in a specified operable and committable state at the start of a mission, when the mission is called for at ...
and
maintainability
In engineering, maintainability is the ease with which a product can be maintained to:
* correct defects or their cause,
* Repair or replace faulty or worn-out components without having to replace still working parts,
* prevent unexpected working ...
characteristics of the system of interest determine the parameters to minimize. Parameters often considered are the cost of failure, the cost per time unit of "downtime" (for example: revenue losses), the cost (per time unit) of
corrective maintenance
Corrective maintenance is a maintenance task performed to identify, isolate, and rectify a fault so that the failed equipment, machine, or system can be restored to an operational condition within the tolerances or limits established for in-servi ...
, the cost per time unit of
preventive maintenance
The technical meaning of maintenance involves functional checks, servicing, repairing or replacing of necessary devices, equipment, machinery, building infrastructure, and supporting utilities in industrial, business, and residential installa ...
and the cost of
repairable system replacement
assady and Pohl The foundation of any maintenance model relies on the correct description of the underlying deterioration process and failure behavior of the component, and on the relationships between maintained components in the product breakdown (system / sub-system / assembly / sub-assembly...).
Optimal Maintenance strategies are often constructed using stochastic models and focus on finding an optimal
inspection time or the optimal acceptable degree of system degradation before maintenance and/or replacement. Cost considerations on an Asset scale may also lead to select a "run-to-failure" approach for specific components.
There are four main survey papers available accomplished to cover the spectrum of optimal maintenance:
* Optimal maintenance models for systems subject to failure–a review by YS Sherif, ML Smith published in Naval Research Logistics Quarterly, 1981.
* C. Valdez-Flores, R.M. Feldman, “A survey of preventive maintenance models for stochastically deteriorating single-unit systems”, Naval Research Logistics, vol 36, 1989 Aug, pp 419–446.
* J.J. McCall, “Maintenance policies for stochastically failing equipment:a survey”, Management Science, vol 11, 1965 Mar, pp 493–524.
*
W.P. Pierskalla, J.A. Voelker, “A survey of maintenance models: The control and surveillance of deteriorating systems”, Naval Research Logistics Quarterly, vol 23, 1976 Sep, pp 353–388.
Operations research