A MODEL FOR SCHEDULING MAINTENANCE UTILIZING MEASURES OF EQUIPMENT PERFORMANCE

A METHOD IS DESCRIBED FOR SCHEDULING PREVENTIVE MAINTENANCE TO MINIMIZE EXPECTED AVERAGE HOURLY MAINTENANCE COST BASED ON A CRITERION OF PERIODICALLY OBSERVING DETERIORATION IN ONE OR MORE EQUIPMENT PERFORMANCE CHARACTERISTICS. THE MATHEMATICAL PROCEDURE REQUIRES EXPRESSING THE DETERIORATION PHENOMENON IN THE FORM OF A SIMPLE MARKOV PROCESS. THE IMPLICATION OF THIS METHOD IS THAT A FORECAST OF EQUIPMENT FAILURE IS BASED ONLY ON EXISTING PERFORMANCE LEVEL AND IS INDEPENDENT OF ANY HISTORY OF PRIOR DETERIORATION RATE. THE CRITERION FOR SCHEDULING PREVENTIVE MAINTENANCE IS EXPRESSED AS A METHOD INVOLVING MATRIX MULTIPLICATION RATHER THAN AS A SIMPLE ALGEBRAIC FORMULA OR A SERIES OF CURVES. THIS WAS NECESSITATED BY THE LARGE NUMBER OF INPUT PARAMETERS CONSISTING OF MAINTENANCE COST PARAMETERS AND A MATRIX OF PROBABILITIES DESCRIPTIVE OF THE DETERIORATION PHENOMENON. HYPOTHETICAL NUMERICAL EXAMPLES ESTABLISHED THE POTENTIAL OF THIS METHOD FOR ACHIEVING REAL SAVING IN MAINTENANCE COST. THE METHOD PROVIDES A SYSTEMATIC SEARCH FOR LEMON EQUIPMENTS, AND, CONVERSELY, PROTECTS AGAINST DISCARDING THOSE EQUIPMENTS WHICH TEND TO MAINTAIN HIGH PERFORMANCE LEVELS OVER EXTENDED PERIODS OF TIME. THE ALGEBRAIC METHOD PROVIDES A TECHNIQUE FOR COLLECTING DETERIORATION DATA IN TERMS OF DISTRIBUTIONS AND NOT JUST AVERAGES. IT WAS APPARENT IN THE NUMERICAL WORK THAT THE UNDERLYING FAILURE DENSITY FUNCTION IS CRITICAL IN DETERMINING THE AMOUNT OF SAVING WHICH CAN BE ACHIEVED BY THIS METHOD. THE COEFFICIENT OF VARIATION IS ESPECIALLY CRITICAL. THE METHOD IS DISTRIBUTION FREE SINCE IT DOES NOT DEPEND ON PRIOR KNOWLEDGE OF THE TIME TO FAILURE DENSITY FUNCTION. THE METHODS OF DATA COLLECTION, DEFINITION OF STATES OR PERFORMANCE LEVELS, AND THE SELECTION OF PROPER TIME INTERVALS PRESENT PECULIAR PROBLEMS WHICH REQUIRE CARE IN THE APPLICATION OF THIS METHOD. /AUTHOR/

  • Supplemental Notes:
    • Publ No 101-21-150, 49 PP, 8 FIG, 6 TAB
  • Corporate Authors:

    ARINC Research Corporation

    2251 Riva Road
    Annapolis, MD  USA  21401
  • Authors:
    • Bradley, C E
    • Welker, E L
  • Publication Date: 1959-10-1

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Filing Info

  • Accession Number: 00219266
  • Record Type: Publication
  • Source Agency: Clearinghouse Fed Sci & Tech Info
  • Files: TRIS
  • Created Date: Sep 5 1994 12:00AM