Aircraft engine reliability analysis using lower confidence limit estimate procedures.

102 Pages·1.3 MB·en_US

by  Baldwin, Richard P.;Woods, W. Max.

NAVAL POSTGRADUATE SCHOOL
Monterey, California
THESIS
AIRCRAFTENGINE RELIABILITY ANALYSIS
USING
LOWERCONFIDENCE LIMITESTIMATE PROCEDURES
by
RichardP. Baldwin
December, 1992
ThesisAdvisor: W. M. Woods
Approved for public release; distribution is unlimited
T260209

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4 PERFORMINGORGANIZATION REPORTNUMBER(S) 5 MONITORINGORGANIZATION REPORTNUMBER(S)
6a NAMEOFPERFORMINGORGANIZATION 6b OFFICESYMBOL 7a NAMEOFMONITORINGORGANIZATION
NavalPostgraduateSchool (Ifapplicable) NavalPostgraduateSchool
36
6c.ADDRESS(City,State,andZIPCode) 7b ADDRESS{City.State,andZIPCode)
Monterey,CA 93943-5000 Monterey,CA 93943-5000
8a NAMEOFFUNDING/SPONSORING 8b OFFICESYMBOL 9 PROCUREMENTINSTRUMENTIDENTIFICATIONNUMBER
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11.TITLE (IncludeSecurityClassification)
AIRCRAFTENGINE RELIABILITYANALYSISUSINGLOWERCONFIDENCELIMITESTIMATE PROCEDURES
12 PERSONALAUTHOR(S) Baldwin,RichardP.
13a.TYPEOFREPORT 13b TIMECOVERED 14 DATEOFREPORT(year,month,day) 15 PAGECOUNT
Master'sThesis From To 92,12,14 92
16.SUPPLEMENTARY NOTATION
TheviewsexpressedinthisthesisarethoseoftheauthoranddonotreflecttheofficialpolicyorpositionoftheDepartmentofDefenseorthe U.S.
Government.
17 COSATICODES 18 SUBJECTTERMS(continueonreverseifnecessaryandidentifybyblocknumber)
FIELD GROUP SUBGROUP Spreadsheet,NALDA,F404,LOTUSApplication
19 ABSTRACT(continueonreverseifnecessaryandidentifybyblocknumber)
Inthisthesis,aspreadsheetmodelwasdevelopedtocomputethelowerconfidencelimit(LCL)forthereliabilityofacomplexweaponsystem
usingapersonalcomputer.TheLCLiaan estimateofthelowestreliabilityasystemisexpectedtohaveatagivenpointintimewithagivenlevel
ofconfidence.Thereliabilitymodel isbasedonaWeibulldistributionforthesystemcomponentfailuretimes.Thereliability LCLprocedureshas
beenextensivelyvalidatedanddeterminedtobequiteaccuratewhentheexpectednumberoffailuresisatleast10.
ThemodeliscapableofsupportingLCLdecisionsinsupportoftheComponentImprovementProgram oranewweaponsystemprocurement
wherereliabilitygrowthanalysisisusedasadecisionsupporttool.Thisprocedurealsoprovidesprogrammanagersandengineerswithamethod
toperformLCLanalysisandtherebyreducetheirdependenceoncontractorsuppliedreliabilitydata..
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22a.NAMEOFRESPONSIBLE INDIVIDUAL 22b TELEPHONE(IncludeAreacode) 22c.OFFICESYMBOL
W.M.Woods [phone] OR/WO
DD FORM 1473,84MAR 83APReditionmaybeuseduntilexhausted SECURITYCLASSIFICATIONOFTHIS PAGE
Allothereditionsareobsolete Unclassified
Approved for public release; distribution is unlimited.
AircraftEngine Reliability Analysis
using
Lower Confidence LimitEstimate Procedures
by
Richard P. Baldwin
LieutenantCommander, United States Navy
B.S., University ofWashington, 1980
Submitted in partial fulfillment
ofthe requirements for the degree of
MASTER OF SCIENCE IN MANAGEMENT
from the
NAVAL POSTGRADUATE SCHOOL
^
December 1992
ABSTRACT
In this thesis, a spreadsheet model was developed to
compute the lower confidence limit (LCD for the reliability
of a complex weapon system using a personal computer. The LCL
is an estimate of the lowest reliability a system is expected
to have at a given point in time with a given level of
confidence. The reliability model is based on a Weibull
distribution for the system component failure times. The
reliability LCL procedures has been extensively validated and
determined to be quite accurate when the expected number of
failures is at least 10.
This model is capable of supporting LCL decisions in
support of the Component Improvement Program or new weapon
system procurement where reliability growth analysis is used
as a decision support tool. This procedure also provides
program managers and engineers with a method to perform LCL
analysis and thereby reduce their dependence on contractor
supplied reliability data.
111
Qi>
6.1
TABLE OF CONTENTS
I. INTRODUCTION 1
A. PURPOSE 2
B. LOWER CONFIDENCE LIMIT PROCEDURE BACKGROUND . . 3
C. RELIABILITY BLOCK MODEL 4
D. METHODOLOGIES 5
E. THESIS ORGANIZATION 7
F. SUMMARY 8
II. NAVAL AVIATION LOGISTICS DATA ANALYSIS (NALDA) 9
. .
A. HISTORICAL BACKGROUND 9
B. NALDA APPLICATION AND DATA COLLECTION PROGRAMS 9
...
C. DATABASE MANAGEMENT SYSTEM 2000 CONCEPTS 12
1. Data Structure 12
2. Kinds of Data 13
D. NALDA DATA ACCURACY AND INTEGRITY 16
E. POSSIBLE NALDA DBMS IMPROVEMENTS 17
F. SUMMARY 17
III. DESCRIPTION OF THE LOWER CONFIDENCE LIMIT
PROCEDURE 18
A. INTERVAL ESTIMATE PROCEDURE FOR WEIBULL FAILURE
TIMES 18
IV