Spelling suggestions: "subject:"dissertations -- bechanical engineering"" "subject:"dissertations -- amechanical engineering""
141 |
The CFD simulation of an axial flow fanLe Roux, Frederick Nicolaas 03 1900 (has links)
Thesis (MScEng (Mechanical and Mechatronic Engineering))--University of Stellenbosch, 2010. / ENGLISH ABSTRACT: The purpose of this project is to investigate the method and accuracy of simulating
axial ow fans with three-dimensional axisymmetric CFD models. Two
models are evaluated and compared with experimental fan data. Veri cation
data is obtained from a prototype fan tested in a facility conforming to the BS
848 standards. The ow eld over the blade surfaces is investigated further
with a visualization experiment comprising of a stroboscope and wool tufts.
Good correlation is found at medium to high ow rates and recommendations
are made for simulation at lower ow rates as well as test guidelines at the fan
test facility. The results and knowledge gained will be used to amend currently
used actuator disc theory for axial ow fan simulation. / AFRIKAANSE OPSOMMING: Die doel van hierdie projek is om die metode en akkuraatheid om aksiaalvloeiwaaiers
met drie-dimensionele BVM modelle te simuleer, te ondersoek. Twee
modelle word geëvalueer en met eksperimentele waaiertoetse vergelyk. Veri-
kasie data is verkry vanaf 'n prototipe waaier wat in 'n fasiliteit getoets is en
wat aan die BS 848 standaarde voldoen. Die vloeiveld oor die lemoppervlaktes
word ondersoek met 'n visualisering eksperiment wat uit 'n stroboskoop en
wolletjies bestaan. Goeie korrelasie word gevind vir medium tot hoë massavloeie
en aanbevelings word gemaak vir die simulasie by laer massavloeie met
riglyne vir toetswerk in die toets-fasiliteit. Die resultate en kennis opgedoen
sal gebruik word in die verbetering van huidige aksieskyfteorie vir numeriese
aksiaalvloeiwaaier simulasies.
|
142 |
A computational fluid dynamics study of the near surface wind patterns over a desert dune and the effect on seed dispersionJoubert, Eugene Christiaan 03 1900 (has links)
Thesis (MScEng)--Stellenbosch University, 2010. / ENGLISH ABSTRACT: This project originated when a team of scientists at the Gobabeb training and research and centre
observed seed accumulation sites on the slope of sand dunes in the Namib Desert. Seeds that
accumulate on the slip face of a sand dune provide food for small desert creatures that in turn
attract larger animals, resulting in a small ecosystem on the side of the dune. Since wind is the
primary transport of seeds throughout the Namib Desert it is of interest to investigate wind
patterns over the dune. In this project it is therefore desired to look at seed dynamics and
deposition as a result of near surface wind patterns around a three-dimensional dune geometry
using computational fluid dynamics. The project is a joint venture between the University of
Stellenbosch and the University of Namibia. This document presents the South African MScEng
thesis part.
The literature review shows the dominant winds in the Namib Desert to be from the south to
westerly direction. Previous studies on air flow over dunes focussed on sand movement and were
often limited to simplified two-dimensional geometries and steady state simulations. From these
studies the basic flow features associated with dunes can be identified. Lastly, factors that
influence particle dynamics around dune geometries are looked at. These particle studies mostly
involve the movement of sand rather than seeds but still provide valuable insight.
The project methodology is explained and includes the equipment used, the considerations taken
into account, the simplifications made as well as the procedure followed when conducting field
work and simulations. A section of an actual Namibian linear dune is mapped in order to obtain
a geometry for the simulations. Flow measurements are carried out with a wind mast to obtain
velocity profile inlet conditions for the simulations. Furthermore, seed sampling is done by the
collaborating Namibian team of which the data is used to obtain an effective seed particle model.
Lastly, simulations are carried out using primarily OpenFOAM-1.5. The simulations look at
general near surface wind patterns, time dependant flow features and particle movement and seed
deposition around and on the linear dune.
The results show different wind profiles for different wind direction. It is also possible to see
how the profile changes as the flow accelerates up the dune slope. Two-dimensional results
provide the opportunity to compare results with previous studies as well as to provide the basis
for looking at aspects such as differencing schemes, turbulence models and parallel computing
before three-dimensional simulations are carried out. The importance of higher order
differencing schemes are confirmed in the two-dimensional results. The turbulence models,
however, produce very similar results. The results from the two- and three-dimensional results
show typical flow features associated with dunes. Transient flow features and separation vortex
structures can be identified from time dependant simulations. Furthermore, particle simulations
reveal how particles tend to be trapped in the recirculation regions.
The conclusions explain how the project objectives were achieved and provide recommendations
for future studies related to this project. / AFRIKAANSE OPSOMMING: Die projek het ontstaan toe naforsers areas van saad akumulasie op die hellings van duine in
Namibë opgelet het. Hierdie akumulasie van plant materiaal verskaf die voedsel vir klein diere
op die duin wat ‘n klein ekosisteem tot gevolg het. Aaangesien die primêre vervoermiddel vir
sade in die woestyn wind is beoog die projek om deur die wind patrone oor die duin beter te
verstaan die saad verspreiding te beskryf. Die doel is dus om saad verspreiding en akumulasie te
beskryf deur die wind patrone te bekyk wat die verspreiding tot gevolg het deur gebruik te maak
van numeriese vloei dinamika. Die projek is ‘n saamgestelde projek tussen die Universiteit van
Stellenbosch en die Universiteit van Namibië. Hierdie dokument behels die Suid Afrikaanse
MScIng gedeelte van die projek.
Deur die hersiening van literatuur word daar gesien dat die domineerende wind rigtings as suid
tot wes beskryf kan word. Vorige studies wat verband hou met wind vloei oor duine wys dat die
meeste op twee-dimensionele eenvoudige geometrië gefokus het met tyd onafhankike simulasies.
Dit is egter moontlik om die resultate te gebruik om karakteristieke vloei patrone te identifiseer
wat met duin wind patrone geassosieer kan word. Laastens word daar gekyk na die faktore wat
partikel beweeging beïnvloed, maar hierdie studies sluit hoofsaaklik sand partikels in eerder as
sade.
Die motodologie beskryf die toerusting, oorwegings en prosedures wat gevolg is tydens veld
werk asook simulasies. Tydens die veld werk is ‘n gedeelte van ‘n Namib lineêre duin gemeet en
so gebruik om ‘n geometrie te maak wat vir simulasie doeleindes gebruik kan word. Daar is ook
wind meetings gedoen met ‘n wind mas om wind profiele vir inlaat kondisies vir die simulasies te
kry. Verder het saad bestudeering die nodige data verskaf om ‘n voledige saad partikel model op
te stel wat in die simulasies gebruik kan word. Laastens kyk die simulasies veral na algemene
vloei patrone, tyd afhanklike vloei effekte en ook partikel beweging in die vloei veld.
Die resultate wys hoe wind profiele verskil wat van verskillende rigtings af waai. Dit is ook
moontlik on te wys hoe die wind profiele verander soos die wind versnel teen die duin op. Tweedimensionele
simulasies verskaf die geleentheid om te kyk na die effek van verkillende
numeriese modelle, turbulensie modelle en ook multi-prosesseerder verwerking. Tydens die
twee-dimensionele simulasies is die belangrikheid van hoër orde numeriese metodes besef. Die
verkillende turbulensie modelle het egter klein verkille gewys. Alby die twee- en driedimensionele
resultate wys karakteristieke vloei patrone wat met duine geasosieer kan word.
Verder het tyd afhanklike simulasies gewys hoe wind patrone verander met tyd. Die partikel
simulasies wys ook die beweging van partikels deur die wind en hoe dit neig om te akumuleer in
die hersirkulasie gebied agter die duin.
Die gevolgtrekkings wys dat al die doelstellings bereik is en maak voorstelle vir toekomstige
studies wat met hierdie studie verband hou.
|
143 |
Prediction of the temperature distribution in asphalt pavement samplesBurger, Marco 04 1900 (has links)
Thesis (MScEng)--Stellenbosch University, 2005. / ENGLISH ABSTRACT: The convection heat transfer coefficient between an infinite, horizontal surface and the natural
environment is determined experimentally. It is shown that, during daytime, heat is
transferred due to natural and forced convection, while during nighttime heat is transferred
due to conduction and forced convection. Equations that correlate the daytime and nighttime
convective heat transfer coefficients respectively, are presented. The results are compared
with values obtained by other investigators.
The equations for the convection heat transfer coefficient are then used to predict the surface
temperature and the temperature at depth of asphalt pavement samples using a simulation
model. It is found that there is good agreement between the measured and the predicted
asphalt pavement sample temperatures. / AFRIKAANSE OPSOMMING: Die konveksie warmteoordrags-koëffisiënt tuseen 'n oneindige, horisontale oppervlak en die
natuurlike omgewing is eksperimenteel bepaal. Daar word getoon dat warmte, tydens die
dag, oorgedra word deur natuurlike en geforseerde konveksie, terwyl warmte tydens die nag
oorgedra word deur geleiding en geforseerde konveksie. Die resultate word vergelyk met die
resultate van ander navorsers. Vergelykings wat die konveksie warmteoordrags-koëffisiënt
gedurende die dag en nag onderskeidelik korreleer word voorgestel.
Die vergelykings vir die konveksie warmteoordrags-koëffisiënt word dan gebruik in 'n
simulasiemodel om die oppervlaktemperatuur en die temperatuur onder die oppervlakte van
asfalt-padoppervlakmonsters te voorspel.
|
144 |
Forced granular flowCoetzee, C. J. (Cornelis Jacobus) 12 1900 (has links)
Thesis (MEng)--University of Stellenbosch, 2000. / ENGLISH ABSTRACT: The main goal of the thesis is to validate the ability of discrete element methods (DEM)
to predict forced granular flow. Granular flow occurs in a broad spectrum of industrial
applications. The thesis focuses on earthmoving processes typical of the mining and
agricultural industries. Existing soil mechanics soil-tool models are also investigated
and general flow behaviour in and around blades and buckets are established.
Soil mechanics theories are used to predict the draft forces on a flat blade moving
through granular material. Com and wheat grains are used as material. The rupture
(slip) lines in front of the blade are predicted by soil mechanics and compared to
experimental results. A two-dimensional test bench is used to visualise the flow of the
granular material. Forces and moments that act on the tools are measured.
DEM can be used to model industrial granular flow with large displacements. Two
types of earthmoving equipment are simulated. The first is a flat blade and the second is
a bucket. The forces on these tools are determined using DEM and compared to
experimental results. The ability of DEM to predict material compressibility, the flow
of material in and around the tools, the rupture lines and the bucket fill rate are
investigated. A particle relative displacement method is used to determine the rupture
lines. / AFRIKAANSE OPSOMMING: Die hoofdoel van die tesis is om die vermoë van diskrete-element-metodes (DEM) om
geforseerde partikelvloei te voorspel, te ondersoek. Partikelvloei word aangetref in 'n
breë spektrum van industriële toepassings. Die tesis fokus op grondverskuiwing soos
aangetref in myn- en landbouprosesse. Bestaande grondmeganika-modelle word ook
ondersoek, asook die algemene gedrag van partikelvloei in en rondom lemme en bakke.
Die grondmeganika-modelle word hoofsaaklik gebruik om die kragte op lemme te
voorspel. Glip (skuif)-vlakke word ondersoek en vergelyk met eksperimentele resultate.
'n Twee-dimensionele toetsbank word gebruik om die vloei waar te neem. Die kragte
en momente op die toerusting word ook gemeet. Mielie- en koringpitte word as
materiaal gebruik.
DEM kan gebruik word om industriële partikelvloei met groot verplasings te modelleer.
Twee tipes toerusting word gesimuleer. Die eerste is 'n plat lem en die tweede 'n bak.
Die kragte en momente op dié toerusting word bepaal m.b.V. DEM en dan vergelyk met
die eksperimentele resultate. Die vermoë van DEM om materiaalsamedrukking,
vloeipatrone, glipvlakke en bakvul-tempo's te voorspel word ondersoek. 'n Partikelrelatiewe-
verplasings-metode word gebruik om die glipvlakke te voorspel.
|
145 |
Aspects of linking CAD and cost estimation softwareLiu, Yang 12 1900 (has links)
Thesis (MScEng)--Stellenbosch University, 2001. / ENGLISH ABSTRACT: This thesis describes a module that links AutoCAD and CeDeas (cost estimation
software which was developed by Department of Mechanical Engineering, University
of Stellenbosch). CeDeas is intended for estimating the direct manufacturing cost of
simple welded assemblies in a batch production environment. It is aimed at use during
late concept design or early detail design.
The link module was developed in Borland C++ Builder. By using COM (Component
Object Model) technology, the link module employs the methods and the properties of
the AutoCAD automation interface to extract manufacturing information that is
required by CeDeas.
The link module prompts the user to pick objects in an AutoCAD drawing and then
determines the values required by CeDeas to estimate the manufacturing cost. The
user can choose between a "direct select method" (which uses the properties of
geometric entities already in the drawing) and a "user define method" (whereby the
user defmes temporary entities or combines aspects of existing entities in the
AutoCAD drawing). With these results and some non-geometric inputs, the user can
get a cost estimate of components and assemblies. After design changes, the link
module can provide CeDeas with updated values with minimal user interaction in
situations where the "direct select method" was used. The designer can therefore
easily use the cost estimates to compare design alternatives to optimise the design.
Validation studies demonstrated the numerical accuracy of the use of the link module.
The link module can be regarded as an extension of CeDeas. At present it only
supports AutoCAD R14, but can be extended to support AutoCAD 2000 and
Mechanical Desktop. / AFRIKAANSE OPSOMMING: 'n Module wat dien as skakel tussen AutoCAD and CeDeas (kosteberamingsagteware
ontwikkel deur die Departement van Meganiese Ingenieurswese, Universiteit van
Stellenbosch) word in hierdie tesis beskryf. Die doel van CeDeas is om die direkte
vervaardiginskoste van eenvoudige, gesweisde samestellings, in 'n lot-produksie
omgewing, te beraam. Dit is gemik op gebruik tydens laat konsepontwerp en vroeë
detailontwerp.
Die skakelmodule is ontwikkel in Borland C++ Builder. Deur van COM (Component
Object Model) tegnologie gebruik te maak, kry die skakelmodule toegang tot die
funksies en eienskappe van AutoCAD se outomatisasie koppelvlak en kan sodoende
die vervaardigingsinligting onttrek wat deur CeDeas benodig word.
Die skakelmodule vra die gebruiker om voorwerpe in 'n AutoCAD tekening te kies en
bepaal dan die waardes wat deur CeDeas benodig word om die vervaardigingskoste te
skat. Die gebruiker kan kies tussen 'n "direkte keuse metode" (wat die eienskappe van
geometriese entiteite wat reeds in die tekening is, gebruik) en 'n "gebruiker definieer
metode" (waarin die gebruiker tydelike entiteite defmieer of kombinasies van aspekte
van bestaande entiteite in die AutoCAD tekening gebruik). 'n Koste beraming van
komponente of samestellings kan verkry word met hierdie inligting tesame met ander
nie-geometriese inligting. Na ontwerpsveranderings, kan die skakelmodule hersiene
waardes vir CeDeas voorsien met minimale gebruikers-interaksie in gevalle waar die
"direkte keuse metode" gebruik is. Die gebruiker kan daarom maklik die
kosteskattings gebruik om ontwerpsaltematiewe te vergelyk om die ontwerp te
optimeer.
Evalueringstudies het die numeriese akkuraatheid van die skakelmodule bevesting.
Hierdie module kan as 'n uitbreiding van CeDeas beskou word. Tans werk die module
slegs met AutoCAD R14, maar dit kan uitgebrei word om met AutoCAD 2000 en
Mechanical Desktop te werk.
|
146 |
Effect of a diffuser on the power production of an ocean current turbineReinecke, Josh 03 1900 (has links)
Thesis (MScEng (Mechanical and Mechatronic Engineering))--University of Stellenbosch, 2011. / Please refer to full text to view abstract.
|
147 |
Performance trends of a large air-cooled steam condenser during windy conditionsLouw, Francois G. 03 1900 (has links)
Thesis (MScEng (Mechanical and Mechatronic Engineering))--University of Stellenbosch, 2011. / Please refer to full text to view abstract.
|
148 |
Development and validation of a numerical model for an inflatable paper dunnage bag using finite element methodsVenter, Martin Philip 03 1900 (has links)
Thesis (MScEng (Mechanical and Mechatronic Engineering))--University of Stellenbosch, 2011. / Please refer to full text to view abstract. / Imported from http://etd.sun.ac.za. / np2011
|
149 |
Effect of water maldistribution on cooling tower fill performance evaluationBertrand, Timothy Paul 03 1900 (has links)
Thesis (MScEng (Mechanical and Mechatronic Engineering))--University of Stellenbosch, 2011. / ENGLISH ABSTRACT: A 1.5 x 1.5 m2 counter-flow fill performance test facility is described in detail.
Instrumentation was selected and installed in the cooling tower fill test facility and
calibrated to ensure measurement accuracy. A facility control program was written
to simplify the operation of the test facility via a user interface. The program
calculates automatically the Merkel number and loss coefficients as measures of
fill thermal and flow performance respectively. A spray frame was designed and
manufactured to ensure uniform water distribution to the fill. The water
distribution through different fills with varying fill heights and different water
flow rates was measured. The water attached to the walls of the test facility was
examined.
Film, trickle and splash fills are tested in the upgraded test facility. The film and
trickle fill performance determined during testing is deemed acceptable as these
fills have minimal migration effects. Fills with poor distribution effects and large
migration of water towards the walls of the test facility, like the splash fill tested,
cannot to be tested accurately in a 1.5 x 1.5 m2 test section as the results do not
represent the performance of the fill in a relatively large cooling tower.
Other aspects examined were:
• air flow uniformity
• air fill bypass effects
• location of water inlet and outlet temperature measurement points
• location of pressure measurement probes.
It was determined that, in the current test facility:
• air uniformity is suitable for performance testing
• air bypass effects can be ignored for open fills and can be minimised for
dense fills by packing sponge between the fill and walls
• water inlet and outlet temperatures should be measured in the pipe-work,
resulting in a measurement method that is not influenced by the relative
weightings of each thermocouple
• pressure difference over the fill height measured by the pressure
measurement tap is independent of its location on the fill outlet plane
provided the pressure measurement points are perpendicular to the air
stream and are not against the walls. / AFRIKAANSE OPSOMMING: 'n 1.5 x 1.5 m² Teenvloei pakking werkverrigting toetsfasiliteit word in detail
beskryf. Instrumentasie is gekies en geïnstalleer in die koeltoring pakking
toetsfasiliteit en gekalibreer om akkuraatheid te verseker. 'n Fasiliteit beheer
program is geskryf om die gebruik van die toetsfasiliteit te vereenvoudig. Die
program het ‘n vriendelike gebruikers intervalk. Die program bereken outomaties
die Merkel-getal en verlies koëffisiënte as mate van pakking termiese- en vloeiwerksverrigting.
'n Sproeiraam is ontwerp en vervaardig om uniforme water
verspreiding aan die pakking te verseker. Die water verspreiding deur verskillende
pakkings met verskillende pakking hoogtes en water vloei snelhede is gemeet. Die
water aangeheg aan die mure van die toetsfasiliteit is ook ondersoek.
Film, druppel en spat pakkings word in die opgegradeerde toetsfasiliteit getoets.
Die film- en druppelpakking werksverrigting bepaal tydens die toetse is
aanvaarbaar, aangesien hierdie pakkings minimale migrasie effekte het. Pakking
met swak verspreiding effekte en 'n groot migrasie van water na die wande van die
toetsfasiliteit, soos gevind met die spatpakking toetse, kan nie met akkuraatheid in
'n 1.5 x 1.5 m² toets seksie getoets word nie omdat die resultate nie die
werkverrigting van die pakking verteenwoordig in 'n relatief groot koeltoring.
Ander aspekte wat ondersoek was:
• lugvloei uniformiteit
• lug omleiding effeckte
• die posisie van water in- en uitlaat temperatuur meetpunte
• posisie van die drukmeetapparaat.
Dit is vasgestel dat, in die huidige toetsfasiliteit
• lugvloei eenvormigheid geskik is vir prestasietoetsing
• lug omleiding effekte kan geïgnoreer word vir oop pakkings en kan
verklein word vir digte pakkings deur spons tussen die pakking en mure te
pak
• water inlaat- en uitlaattemperature behoort gemeet te word in die pypwerk
en lei tot 'n metings metode wat nie beïnvloed word deur die relatiewe
gewigte van elke thermokoppel nie
• die druk verskil gemeet deur die drupmeetpunte oor die pakkinghoogte is
onafhanklik van hul posisie op die pakkinguitlaatvlak op voorwaarde dat
die drukmeetpunte loodreg is teen die lugstroom en nie teen die mure nie.
|
150 |
Machining of powder metal titaniumSobiyi, Kehinde Kolawole 03 1900 (has links)
Thesis (MScEng (Mechanical and Mechatronic Engineering))--University of Stellenbosch, 2011. / ENGLISH ABSTRACT: The purpose of this study is to investigate the machinability of commercially pure (CP)
titanium, manufactured using the press-and-sinter PM process.
To this end, CP titanium powder (-200 mesh) was compacted and sintered in vacuum
(10-4 torr) for two hours at 1200°C. Small cylindrical samples were compacted at
pressures varying from 350 to 600 MPa in order to determine the compressibility of the
powder. Following these tests, four larger stepped-cylinder samples were compacted at
pressures close to 400 MPa and sintered under similar conditions. These samples had
sintered densities varying between 3.82 and 4.41 g/cm3. They were used to evaluate the
machinability of the sintered titanium using face turning machining tests.
The samples were machined dry, using uncoated carbide (WC-Co) cutting tool. Cutting
speeds between 60-150 m/min were evaluated while keeping the feed rate and depth of
cut constant at 0.15 mm/rev and 0.5 mm, respectively. The final machined surface finish
and the tool wear experienced during the face turning machining tests were monitored in
order to evaluate PM titanium’s machining performance.
This study showed that it is possible to use the press-and-sinter PM process with CP
titanium powder, with a particle size of less than 75 μm (-200 mesh), to manufacture
sintered titanium. However, particle shape influences the compressibility of the powder
and pressing parts of larger volume, such as the machining test sample shape, is
challenging when using such small particle size powder. Processing conditions, such as
compaction pressure, sintering temperature and sintering time, influence the sintered
density.
Results from the machinability tests show that tool wear increases with a decrease in the
porosity of the sintered titanium. A more porous sintered material has both lower strength
and thermal conductivity. As these factors have opposing effects on the machinability of
materials, it is concluded that the strength of the sintered titanium has a stronger influence
on its machinability than the thermal conductivity.
The cutting tool wear was uniform but showed indications of crater wear. The machined
surface of the denser parts had minimal defects compared to less dense parts. Chip shape
is long for the dense parts, and spiral for the less dense parts. The chips formed were all
segmented, which is typical for titanium.
The machinability of the sintered CP titanium was compared to that of wrought titanium
alloys. As expected, it was found that the machinability of the sintered titanium was poor
in comparison. / AFRIKAANSE OPSOMMING: Die doel van hierdie studie is om die masjineerbaarheid van kommersieel suiwer (KS)
titaan, wat deur die pers-en-sinter poeiermetallurgie (PM) metode vervaardig word, te
ondersoek.
Om hierdie doel te bereik, is KS titaan poeier (-200 ogiesdraad) gekompakteer en gesinter
in ‘n vakuum (10-4 torr) teen 1200°C vir 2 ure. Klein silindriese monsters is tussen drukke
van 350en 600 MPa gekompakteer om die samedrukbaarheid van die poeier te bepaal. Na
aanleiding van hierdie toetse, is vier groter trapvormige-silinder monsters by drukke naby
aan 400MPa gekompakteer en onder soortgelyke omstandighede gesinter. Hierdie
monsters het gesinterde digthede tussen 3.82 en 4.41 g/cm3 gehad. Hulle is gebruik om
die masjineerbaarheid van die gesinterde titaan te ondersoek deur middel van vlak-draai
masjineringstoetse.
Die monsters is sonder smeermiddel gemasjineer met onbedekte karbied (WC-Co)
snygereedskap. Snysnelhede tussen 60 – 150 m/min is geëvalueer terwyl die voertempo
en diepte van die snit konstant by 0.15 mm/rev en 0.5 mm, onderskeidelik, gehou is. Die
finale gemasjineerde oppervlak afwerking en gereedskapsslytasie tydens die vlak-draai
masjinering toets is van die faktore wat gemonitor is sodat PM titaan se optrede tydens
masjinering geëvalueer kan word.
Hierdie studie wys dat diepers-en-sinter metode wel met KS titaan poeier, met ‘n partikel
grootte van minder as 75 μm (-200 maas), gebruik kan word om gesinterde titaan te
vervaardig. Die partikelgrootte beïnvloed wel die samedrukbaarheid van die poeier. Die
samedrukking van parte met groter volume, soos bv die masjinerings toetsmonster, is
uitdagend wanneer klein partikelgrootte poeier gebruik word. Proses omstandighede, soos
kompaksie druk, sinteringstemperatuur en sinteringstyd, beïnvloed die gesinterde
digtheid.
Resultate van die masjineerbaarheidstoetse wys dat beitelslytasie toeneem met ‘n afname
in porositeit van die gesinterede titaan. ‘n Meer poreus gesinterde materiaal het beide laer
sterkte en termiese geleidingsvermoë. Aangesien hierdie faktore teenoorgestelde
uitwerkings op masjineerbaarheid het, word dit dan afgelei dat die sterkte van gesinterde
titaan ‘n groter invloed het op sy masjineerbaarheid as die termiese geleidingsvermoë.
Die beitel se slytasie is hoofsaahlik, maar het tekens van kraterslytasie getoon. Die
gemasjineerde oppervlak van die meer digte onderdele of toetsmonters het min gebreke
gehad in vergelyking met die minder digte dele. Die vorm van die spaanders is lank vir
digte parte, en spiraalvormig vir minder digte toetsmonsters. Die spaanders wat gevorm
het, was almal gesegmenteerd, wat tipies is vir titaan.
Die masjineerbaarheid van die gesinterde KS titaan is met dié van gesmede titaanallooie
vergelyk. Soos verwag is, is gevind dat die masjineerbaarheid van die gesinterde titaan in
vergelyking swak is.
|
Page generated in 0.1768 seconds