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Regression analysis of caterpillar 793D haul truck engine failure data and through-life diagnostic information using the proportional hazards modelCarstens, Wiehahn Alwyn 03 1900 (has links)
Thesis (MScEng)--Stellenbosch University, 2012. / ENGLISH ABSTRACT: Physical Asset Management (PAM) is becoming a greater concern for companies
in industry today. The widely accepted British Standards Institutes’ specification
for optimized management of physical assets and infrastructure is PAS55.
According to PAS55, PAM is the “systematic and co-ordinated activities and practices
through which an organization optimally manages its physical assets, and
their associated performance, risks and expenditures over their life cycle for the
purpose of achieving its organizational strategic plan”.
One key performance area of PAM is Asset Care Plans (ACP). These plans
are maintenance strategies which improve or ensure acceptable asset reliability
and performance during its useful life. Maintenance strategies such as Condition
Based Maintenance (CBM) acts upon Condition Monitoring (CM) data, disregarding
the previous failure histories of an asset. Other maintenance strategies,
such as Usage Based Maintenance (UBM), is based on previous failure histories,
and does not consider CM data.
Regression models make use of both CM data and previous failure histories
to develop a model which represents the underlying failure behaviour of the asset
under study. These models can be of high value in ACP development due to the
fact that Residual Useful Life (RUL) can be estimated and/or the long term life cycle cost can be optimized.
The objective of this thesis was to model historical failure data and CM data
well enough so that RUL or optimized preventive maintenance instant estimations
can be made. These estimates were used in decision models to develop maintenance
schedules, i.e. ACPs.
Several regression models were evaluated to determine the most suitable model
to achieve the objectives of this thesis. The model found to be most suitable for
this research project was the Proportional Hazards Model (PHM). A comprehensive
investigation on the PHM was undertaken focussing on the mathematics and
the practical implementation thereof.
Data obtained from the South African mining industry was modelled with the
Weibull PHM. It was found that the developed model produced estimates which
were accurate representations of reality. These findings provide an exciting basis
for the development of futureWeibull PHMs that could result in huge maintenance
cost savings and reduced failure occurrences. / AFRIKAANSE OPSOMMING: Fisiese Bate Bestuur (FBB) is besig om ’n groter bekommernis vir maatskappye
in die bedryf te word. Die Britse Standaarde Instituut se spesifikasie vir optimale
bestuur van fisiese bates en infrastruktuur is PAS55. Volgens PAS55 is FBB die
“sistematiese en gekoördineerde aktiwiteite en praktyke wat deur ’n organisasie
optimaal sy fisiese bates, hul verwante prestasie, risiko’s en uitgawes vir die doel
van die bereiking van sy organisatoriese strategiese plan beheer oor hul volle lewensiklus
te bestuur”.
Een Sleutel Fokus Area (SFA) van FBB is Bate Versorgings Plan (BVP) ontwikkeling.
Hierdie is onderhouds strategieë wat bate betroubaarheid verbeter of
verseker tydens die volle bruikbare lewe van die bate. Een onderhoud strategie
is Toestands Gebasseeerde Onderhoud (TGO) wat besluite baseer op Toestand
Monitering (TM) informasie maar neem nie die vorige falingsgeskiedenis van die
bate in ag nie. Ander onderhoud strategieë soos Gebruik Gebasseerde Onderhoud
(GGO) is gebaseer op historiese falingsdata maar neem nie TM inligting in ag nie.
Regressiemodelle neem beide TM data en historiese falings geskiedenis data in
ag ten einde die onderliggende falings gedrag van die gegewe bate te verteenwoordig. Hierdie modelle kan baie nuttig wees vir BVP ontwikkeling te danke aan die
feit dat Bruikbare Oorblywende Lewe (BOL) geskat kan word en/of die langtermyn
lewenssilus koste geoptimeer kan word.
Die doelwit van hierdie tesis was om historiese falingsdata en TT data goed
genoeg te modelleer sodat BOL of optimale langtermyn lewensiklus kostes bepaal
kan word om opgeneem te word in BVP ontwikkeling. Hierdie bepalings word dan
gebruik in besluitnemings modelle wat gebruik kan word om onderhoud skedules
op te stel, d.w.s. om ’n BVP te ontwikkel.
Verskeie regressiemodelle was geëvalueer om die regte model te vind waarmee
die doel van hierdie tesis te bereik kan word. Die mees geskikte model vir die navorsingsprojek
was die Proporsionele Gevaarkoers Model (PGM). ’n Omvattende
ondersoek oor die PGM is onderneem wat fokus op die wiskunde en die praktiese
implementering daarvan.
Data is van die Suid-Afrikaanse mynbedryf verkry en is gemodelleer met behulp
van die Weibull PGM. Dit was bevind dat die ontwikkelde model resultate
geproduseer het wat ’n akkurate verteenwoordinging van realiteit is. Hierdie bevindinge
bied ’n opwindende basis vir die ontwikkeling van toekomstige Weibull
Proporsionele Gevaarkoers Modelle wat kan lei tot groot onderhoudskoste besparings
en minder onverwagte falings.
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A simplified numerical decision making toolbox for physical asset management decisionsBurnett, Sulene 12 1900 (has links)
Thesis (MEng)--Stellenbosch University, 2013. / ENGLISH ABSTRACT: The management of physical assets has become a popular eld of
study over recent years and is being acknowledged in multiple disciplines
world wide. In this project, research on Physical Asset Management
(PAM), maintenance and decision making are presented. PAM
is a complex subject and requires the participation of multiple disciplines
in order to successfully manage physical assets. Moreover, the
management of maintenance makes a big contribution in achieving
successful PAM. Decision making is a core element to manage maintenance
e ciently, both on strategic and operational level. Various
methods and techniques can be used to aid the decision making process
such as, using past experience, xed decision making techniques
and techniques involving numerical calculations, to mention only a
few. However, using numerical calculations to make decisions are not
very popular. This is due to various reasons, for example the inherent
complexity of the mathematics and the time required to execute such
calculations are disliked. People tend to avoid complex numerical
calculations and rather rely on past experience and discussion of circulating
opinions to make decisions. This is not ideal and can lead to
inconsistent and inaccurate decisions. In this project, the importance
of numerical decision making is researched, especially in maintenance
related decisions. The focus is placed on the simpli cation of numerical
decision making techniques with the aim to make it easy and quick
to use to support operational PAM decisions. Di erent decisions regarding PAM, especially decisions with regards
to managing maintenance in order to achieve PAM, are discussed by means of a literature study. This is done to clarify the applicability
of using numerical decision making techniques to support this
type of decisions. A few di erent available numerical techniques are
highlighted that can be used to support the decision making process.
The decisions together with numerical decision making techniques are
evaluated in order to combine the most appropriate techniques in a
simpli ed manner. The purpose of this is that it can be used by anyone
with the necessary knowledge of a speci c system or operation.
As a result a simpli ed numerical decision making toolbox is developed
that can support maintenance related decision. This toolbox is
applied to a real life situation by means of a case study, made possible
by Anglo American Platinum Limited (Amplats). An evaluation and
validation of the toolbox is done through the case study to conclude
wether it has value in practice or not. / AFRIKAANSE OPSOMMING: Die bestuur van siese bates het die afgelope paar jaar 'n gewilde
studieveld geword en word erken in verskeie dissiplines reg oor die
w^ereld. In hierdie projek word navorsing gedoen oor Fisiese Bate
Bestuur (FBB), instandhouding en besluitneming. FBB is 'n komplekse
onderwerp en vereis die deelname van verskeie dissiplines om
sukses te behaal. Die bestuur van instandhouding maak 'n groot bydrae
tot suksesvolle FBB. 'n Kern element van doeltre ende instandhouding
is besluitneming, beide op strategiese en operasionele vlak.
Verskillende metodes en tegnieke kan gebruik word om die besluitnemingsproses
te ondersteun soos byvoorbeeld om gebruik te maak van
ondervinding en vorige gebeurtenisse, vaste besluitnemingstegnieke,
tegnieke wat numeriese berekeninge gebruik en nog meer. Die gebruik
van numeriese metodes om besluite te neem is nie baie gewild
nie. Dit is as gevolg van verskeie redes soos byvoorbeeld die inherente
kompleksiteit en ingewikkeldheid van die wiskunde en ook die tyd
wat benodig word om sulke berekeninge uit te voer. Mense is geneig
om ingewikkelde numeriese berekeninge te vermy en eerder staat te
maak op vorige ervaring en die bespreking van menings om besluite
te neem. Dit is nie ideaal nie en kan lei tot onkonsekwente besluite,
of selfs verkeerde besluite. In hierdie projek is die belangrikheid van
numeriese besluitneming nagevors, veral in die onderhoudsverwante
besluite. Die fokus word geplaas op die vereenvoudiging van die numeriese
besluitnemings tegnieke. Die doel is om dit op so 'n manier
te vereenvoudig dat dit maklik en vinnig is om te gebruik vir operasionele
FBB besluite. Verskillende besluite oor FBB, veral besluite met betrekking tot instandhouding
om suksesvolle FBB te bereik, word bespreek deur middel
van 'n literatuurstudie. Die literatuurstudie ondersoek die toepaslikheid
van die gebruik van numeriese besluitnemingstegnieke vir hierdie
soort besluite. 'n Paar verskillende beskikbare numeriese tegnieke wat
gebruik kan word om die besluitnemingsproses te ondersteun word uitgelig.
Die besluite, saam met numeriese besluitnemingtegnieke, word
ge evalueer om die mees gepaste tegnieke te kombineer in 'n vereenvoudigde
manier. Uiteindelik moet dit deur enige iemand met die
nodige kennis van 'n spesi eke stelsel of proses gebruik kan word.
As resultaat is 'n vereenvoudigde numeriese besluitnemingstegniekkombinasie
ontwikkel wat besluite verwant aan instandhouding kan
ondersteun. Hierdie tegniek-kombinasie word toegepas in 'n werklike
situasie deur middel van 'n gevallestudie, wat moontlik gemaak is deur
Anglo American Platinum Limited. 'n Evaluering en validering van
die tegniek-kombinasie word gedoen in die gevallestudie om te bepaal
of dit wel waarde het in die praktyk of nie.
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