Analysis of in-flight structural failures of P-3C wing leading edge segments.

130 Pages·1.8 MB·en_US

by  Lott, Dennis A.;Schmidt, Louis V.

DUD. iBRARY
.
NAV v rGRADUATE SCHOOL
f
MONTEREY CA
93943-5101

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ANALYSIS OF IN-FLIGHT STRUCTURAL FAILURES
OF P-3C WING LEADING EDGE SEGMENTS
by
Dennis A. Lott
Lieutenant Commander, United States Navy
B.S., Arizona State University, 1974
Submitted in partial fulfillment
ofthe requirements for the degree of
MASTER OF SCIENCE IN AERONAUTICAL ENGINEERING
from the
NAVAL POSTGRADUATE SCHOOL
June, 1992
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NAMEOF PERFORMINGORGANIZATION 6b.OFFICESYMBOL 7a.NAME OFMONITORINGORGANIZATION
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avalPostgraduateSchool (Ifapplicable) NavalPostgraduateSchool
AA
:.ADDRESS(City,State,andZIPCode) 7b.ADDRESS(City,State, andZIPCode)
lonterey,CA 93943-5000 Monterey,CA 93943-5000
i. NAMEOF FUNDING/SPONSORING 8b.OFFICE SYMBOL 9. PROCUREMENTINSTRUMENTIDENTIFICATION NUMBER
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:.ADDRESS(Crty,State,andZIPCode) 10.SOURCEOF FUNDING NUMBERS
ProgramElementNo. ProjectNo TaskNo. WorkUnitAccession
Number
TITLE (IncludeSecurityClassification)
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NALYSISOFIN-FLIGHTSTRUCTURALFAILURESOFP-3CWINGLEADINGEDGESEGMENTS
!. PERSONALAUTHOR(S) DennisA.Lott
la.TYPEOF REPORT 13b.TIME COVERED 14. DATEOFREPORT(year, month,day) 15. PAGE COUNT
aster'sThesis From To June 1992 118
SUPPLEMENTARY NOTATION
i.
leviewsexpressedinthisthesisarethoseoftheauthoranddonotreflecttheofficialpolicyorpositionoftheDepartmentofDefenseortheU.S.
)vernment.
'.COSATICODES 18.SUBJECTTERMS(continueonreverseifnecessaryandidentifybyblocknumber)
FIELD GROUP SUBGROUP Aeroelasticity,span-loadanalysis,panelmethods,finite-elementanalysis,stresslevels,stress
concentrations,structuralfailure.
).ABSTRACT(continueonreverseifnecessaryandidentifybyblocknumber)
quantativeanalysiswascarriedouttodeterminethestressespresentintheleading-edgesegmentofaP-3Caircraftoperatingwithinand
itsidethenormaloperatingenvelopeoftheaircraft. Thepurposeoftheanalysiswastoascertainwhetheraspecificweaknessmayexistinthe
ading-edgestructurewhichmightendangerfutureoperatingflightcrews. Athree-stepprocessconsistingofastaticaeroelasticspan-load
lalysis,aninviscidtwo-dimensionalpanel-methodanalysis,andfinite-elementanalysiswasemployedinthecourseoftheevaluation. Lift-
>efficientdistributionsfromthewingspan-loadanalyseswereusedinthetwo-dimensionalpanelmethodtodeterminethepressuredistribution
*oundtheleadingedge,whichwasthenusedasinputtothefinite-elementanalysis. Additionally,staticaeroelastic-derivedwing-twisteffects
ereincludedinthestructuralmodel. Theresultsoftheanalysissuggestthattheleadingedgesegmentstudiedmayexperiencestresslevels
ifficienttocausefailurewithinthenormaloperatingenvelope.
). DISTRIBUTION/AVAILABILITYOFABSTRACT 21 ABSTRACTSECURITYCLASSIFICATION
PI UNCLASSIFIED/UNLIMITED ] SAMEASREPORT l"1 DTICUSERS UNCLASSIFIED
!a. NAME OF RESPONSIBLE INDIVIDUAL 22b TELEPHONE (IncludeAreacode) 22c.OFFICE SYMBOL
AA/Sc
ouisV.Schmidt [phone]
D FORM 1473. 84 MAR 83APRedition maybe useduntilexhausted SECURITYCLASSIFICATIONOFTHIS PAGE
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ABSTRACT
A quantitative analysis was carried out to determine the
stresses present in the leading-edge segment of a P-3C
aircraft operating within and outside the normal operating
envelope of the aircraft. The purpose of the analysis was to
ascertain whether a specific weakness may exist in the
leading-edge structure which might endanger future operating
flight crews. A three-step process consisting of a static
aeroelastic span-load analysis, an inviscid two-dimensional
panel method, and finite-element analysis was employed in the
course of the evaluation. Lift-coefficient distributions from
the wing span-load analyses were used in the two-dimensional
panel method to determine the pressure distribution around the
leading edge, which was then used as input to the finite-
element analysis. Additionally, static aeroelastic-derived
wing-twist effects were included in the structural model. The
results of the analysis suggest that the leading edge segment
studied may experience stress levels sufficient to cause
failure within the normal operating envelope.
in
<L.I
THESIS DISCLAIMER
Although certain commercial software products are
referred to in the body of this thesis, such references do not
constitute recommendations for use or endorsements of the
products.
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